Clinical Anatomy for Your Pocket

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Clinical Anatomy for Your Pocket Douglas J. Gould, Ph.D. Associate Professor, Division of Anatomy The Ohio State University College of Medicine Columbus, Ohio

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Copyright © 2009 Lippincott Williams & Wilkins, a Wolters Kluwer business. 351 West Camden Street Baltimore, MD 21201

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Printed in the People’s Republic of China All rights reserved. This book is protected by copyright. No part of this book may be reproduced or transmitted in any form or by any means, including as photocopies or scanned-in or other electronic copies, or utilized by any information storage and retrieval system without written permission from the copyright owner, except for brief quotations embodied in critical articles and reviews. Materials appearing in this book prepared by individuals as part of their official duties as U.S. government employees are not covered by the above-mentioned copyright. To request permission, please contact Lippincott Williams & Wilkins at 530 Walnut Street, Philadelphia, PA 19106, via email at [email protected], or via website at lww.com (products and services). 9 8 7 6 5 4 3 2 1 Library of Congress Cataloging-in-Publication Data Gould, Douglas J. Clinical anatomy for your pocket / Douglas J. Gould. p. ; cm. Includes index. ISBN-13: 978-0-7817-9193-9 (pbk. : alk. paper) ISBN-10: 0-7817-9193-6 (pbk. : alk. paper) 1. Human anatomy— Outlines, syllabi, etc. I. Title. [DNLM: 1. Anatomy. QS 4 G696c 2009] QM31.G68 2009 611—dc22 2008024080 DISCLAIMER Care has been taken to confirm the accuracy of the information present and to describe generally accepted practices. However, the authors, editors, and publisher are not responsible for errors or omissions or for any consequences from application of the information in this book and make no warranty, expressed or implied, with respect to the currency, completeness, or accuracy of the contents of the publication. Application of this information in a particular situation remains the professional responsibility of the practitioner; the clinical treatments described and recommended may not be considered absolute and universal recommendations. The authors, editors, and publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accordance with the current recommendations and practice at the time of publication. However, in view of ongoing research, changes in government regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any change in indications and dosage and for added warnings and precautions.This is particularly important when the recommended agent is a new or infrequently employed drug. Some drugs and medical devices presented in this publication have Food and Drug Administration (FDA) clearance for limited use in restricted research settings. It is the responsibility of the health care provider to ascertain the FDA status of each drug or device planned for use in their clinical practice. To purchase additional copies of this book, call our customer service department at (800) 638-3030 or fax orders to (301) 223-2320. International customers should call (301) 223-2300. Visit Lippincott Williams & Wilkins on the Internet: http://www.lww.com. Lippincott Williams & Wilkins customer service representatives are available from 8:30 am to 6:00 pm, EST.

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Preface Health professions’ curricula around the world are continually evolving: new discoveries, techniques, applications, and content areas compete for increasingly limited time with traditional basic science topics such as gross anatomy. It is in this context that the foundations established in gross anatomy become increasingly important and relevant for absorbing and applying our ever-expanding knowledge of the human body. As a result of the progressively more crowded curricular landscape, students and instructors are finding new ways to maximize precious contact, preparation, and study time through more efficient, high-yield presentation and study methods. Clinical Anatomy for Your Pocket is designed to serve the time-crunched student. The presentation of gross anatomy in bullet and table format streamlines study and exam preparation. This pocket size, quick reference book is portable, practical, and necessary; even at this small size, nothing is omitted and a large number of clinically significant facts, mnemonics, and easy-to-learn concepts are used to complement the tables and inform the reader. I am confident that Clinical Anatomy for Your Pocket will greatly benefit all students attempting to learn clinically relevant anatomy in a variety of settings, including all graduate and professional gross anatomy programs.

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Dedication I dedicate this book to my mother—Margaret. My first teacher.

Acknowledgments I would like to thank the student reviewers for their input into this book: I hope that I have done you justice and created the learning tool that you need. I would also like to thank Dr. Robert DePhilip, the faculty reviewer of Clinical Anatomy for Your Pocket, whose suggestions have proved invaluable in creating an accurate and functional tool for students.

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Contents Preface iii Dedication and Acknowledgments

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1 Thorax . . . . . . . . . . . . . . . . . . . . . . . . 1 2 Abdomen . . . . . . . . . . . . . . . . . . . . . 33 3 Pelvis . . . . . . . . . . . . . . . . . . . . . . . . 77 4 Back . . . . . . . . . . . . . . . . . . . . . . . 113 5 Lower Limb . . . . . . . . . . . . . . . . . . 126 6 Upper Limb . . . . . . . . . . . . . . . . . . 158 7 Head . . . . . . . . . . . . . . . . . . . . . . . . 196 8 Neck . . . . . . . . . . . . . . . . . . . . . . . . 237 List of Mnemonics Index 261

260

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Thorax

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INTRODUCTION The thorax is that portion of the trunk inferior to the neck (superior thoracic aperture) and superior to the diaphragm, to which the pectoral girdle and upper limbs are attached.

THORACIC WALL The bones of the thoracic wall are the ribs and sternum. Ribs 3–9 possess characteristics common to the majority of ribs and so are considered “typical,” whereas ribs 1–2 and 10–12 have specializations or are lacking typical characteristics and so are considered “atypical.” Bones of the thoracic wall Bone Typical ribs (3–9)

Characteristic Head

Neck Tubercle

Body

Atypical ribs (1–2, 10–12 )

• 1st and 2nd ribs—heads • Ribs 10–12 sternal attachments

Significance Bears 2 facets that articulate with vertebra of same number and the vertebra superior to it Joins head with body of rib • Articulates with transverse process of vertebra of same number • Located at junction of neck and body • Bears pronounced angle • Inferior internal border has costal groove for intercostal neurovascular elements • The heads of the first 2 ribs only attach to one vertebral body, unlike typical ribs that attach to two • The 1st and 2nd ribs have additional tubercles for muscle attachments (continued)

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Bones of the thoracic wall (continued) Bone

Characteristic

Significance • Ribs 10–12 attach indirectly (rib 10) or not at all to the sternum (ribs 11–12, the floating ribs)

Thoracic vertebrae (12)

Body

Supports weight

Spinous process

Serve for muscle attachments

Transverse process

Sternum

Laminae and pedicles

Form vertebral arch that encloses spinal cord

Vertebral foramen

• Formed from vertebral arch and posterior aspect of vertebral body • Encloses spinal cord • Successive vertebral foramen form vertebral canal

Vertebral notches— superior and inferior

Inferior and superior notches of adjacent vertebrae form intervertebral foramen that permits passage of spinal nerves between the vertebral canal and periphery

Articulating processes— superior (2) and inferior (2)

Form zygapophyseal joints with articulating processes on adjacent vertebrae

Manubrium

• Superior part of sternum • Superior border bears jugular notch • Clavicular notches (2) are found on each side of the jugular notch for articulation with the clavicles

Sternal angle

• Landmark for the 2nd ribs’ costal cartilage articulation with the sternum • Marks articulation between manubrium and body

Body

Bears costal notches along lateral border for articulation with costal cartilages

Xiphoid process

• Most inferior part of sternum • Landmark for central tendon of diaphragm, superior margin of liver, and inferior border of heart

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Additional Concept True, False, and Floating Ribs Ribs 1–7 are considered “true” ribs, as they attach to the sternum via their individual costal cartilages; ribs 8–10 are considered “false” ribs, as they attach indirectly to the sternum via the costal cartilages of more superior ribs; ribs 11–12 are considered “floating” ribs, as they do not connect to the sternum.

Clinical Significance Rib Fracture Fracture of the upper ribs may injure the lungs and of lower ribs may damage the liver or spleen or may tear the diaphragm. All rib fractures are painful owing to the broken pieces moving during respiration, coughing, sneezing, or laughing. Sternal Puncture A wide-bore needle may be used to harvest bone marrow from the sternum for transplantation or biopsy. Muscles of the thoracic wall (Figures 1-2 and 1-4) Muscle External intercostal Internal intercostal Innermost intercostal Transverse thoracic

Proximal attachment Inferior aspect of ribs

Distal Attachment Innervation Superior Intercostal aspect of ribs nerves

Posterior inferior Posterior aspect of aspect of sternum costal cartilages 2–6 Subcostal Deep aspect of Superior lower ribs, near aspect angles of 2–3 ribs below proximal attachment

Main Actions Elevate ribs Depress and elevate ribs

Depress ribs

Depress and elevate ribs

(continued)

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Muscles of the thoracic wall (continued) Proximal Muscle attachment Diaphragm Sternum, inferior 6 ribs and their costal cartilages, medial & lateral arcuate ligaments, and 1st 3 lumbar vertebrae Levator T7–T11 costarum transverse processes Serratus posterior superior Serratus posterior inferior

Distal Attachment Central tendon of the diaphragm

Subjacent ribs between tubercle and angle Nuchal ligament, 2nd–4th ribs C7–T3 spinous superior processes borders T11–L2 spinous 8th–12th ribs processes inferior borders, near angles

Innervation Motor: phrenic; sensory: phrenic and intercostal nerves

Main Actions Increases the volume of the thorax to cause inspiration

C8–T11 posterior rami

Elevate ribs

2nd–5th intercostals 9th–11th Depress ribs intercostals and subcostal Lung Visceral pleura Pleural cavity

Needle

Parietal pleura Innermost intercostal muscle Intercostal vein, artery, nerve Internal intercostal muscle External intercostal muscle

Tube

FIGURE 1-1. Thoracocentesis. An intercostal nerve block (needle in image) produces anesthesia of an intercostal space by introduction of an anesthetic agent around the intercostal nerve and its collaterals. The tube in the diagram indicates the position for thoracocentesis. (From Dudek RW, Louis TM. High-Yield Gross Anatomy. 3rd ed. Baltimore: Lippincott Williams & Wilkins; 2008:56.)

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Sternum T8 Diaphragm T10 Inferior vena cava Esophagus

T12

Aorta Celiac trunk Superior mesenteric artery

FIGURE 1-2. Holes in diaphragm. There are three large apertures in the diaphragm for major structures to pass to and from the thorax into the abdomen. The caval opening for the inferior vena cava (IVC), most anterior, is at the T8 level and to the right of the midline; the esophageal hiatus, intermediate, is at T10 and to the left of the midline; the aortic hiatus for the aorta passes posterior to the vertebral attachment of the diaphragm in the midline at T12. (From Moore KL, Dalley AF. Clinically Oriented Anatomy. 5th ed. Baltimore: Lippincott Williams & Wilkins; 2006:329.)

Additional Concept Diaphragm The diaphragm has three openings that permit passage of structures between the thorax and abdomen. These openings are found at T8—caval foramen, T10—esophageal hiatus, and T12—aortic hiatus.

Clinical Significance Phrenic Nerve Injury Phrenic nerve injury results in hemiparalysis of the diaphragm and paradoxical movement during inspiration. Instead of descending during inspiration, the paralyzed half ascends in response to increased intra-abdominal pressure.

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Nerves of the thoracic wall (Figures 1-1 and 1-4) Nerve

Origin

Structures Innervated

Intercostals

Anterior rami of T1–T11 Anterior rami of T12

Intercostal muscles and parietal pleura

Subcostal

Abdominal wall musculature and parietal pleura

Rami communicantes

Connect intercostals and subcostal nerves to sympathetic trunk

• White—convey presynaptic sympathetic fibers from spinal nerve to sympathetic chain and visceral afferents to spinal nerves • Gray—convey postsynaptic sympathetic fibers from the sympathetic chain to spinal nerve

Sympathetic trunk

Sympathetic chain ganglia (paravertebral ganglia)

Composed of sympathetic ganglia containing postsynaptic sympathetic cell bodies connected by ascending and descending fibers

Thoracic splanchnics

Sympathetic chain: • Greater— T5–T9 • Lesser— T10–T11 • Least—T12

Convey presynaptic sympathetic fibers to the prevertebral ganglia of the abdomen; convey visceral afferents to the sympathetic chain

Arterial supply of the thoracic wall (Figures 1-1 and 1-4) Artery

Origin

Description

Internal thoracic

Subclavian

Gives rise to anterior intercostals and musculophrenic

Anterior Internal intercostals thoracic (1–6) and musculophrenic (7–9)

Supplies intercostal muscles and parietal pleura

Posterior Supreme intercostal intercostals (1–2) and thoracic aorta Subcostal

Thoracic aorta

Supplies anterolateral abdominal musculature

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Additional Concept Venous Drainage Venous drainage of the thoracic wall generally parallels arterial supply. However, the posterior intercostal veins drain to the azygos system, which is discussed with the posterior mediastinum. Joints of the thoracic wall Joint

Type

Articulation

1st sternocostal

Cartilaginous

1st costal Joint strengthened by cartilage sternocostal radiate with manubrium ligaments

2nd–7th sternocostal

Synovial

2nd–7th costal cartilages with sternum

Sternoclavicular

Synovial

Sternal end of • Divided into two clavicle with compartments by manubrium and articular disc 1st costal cartil- • Joint strengthened age by anterior and posterior sternoclavicular and costoclavicular ligaments

Manubriosternal

Cartilaginous

Manubrium with Joint often fuses in body of sternum older people

Xiphisternal

Structure

Xiphoid process with body of sternum

Interchondral

• 6th–9th: synovial • 9th–10th: fibrous

Costal cartilages Strengthened by of adjacent ribs interchondral 6–10 ligaments

Costochondral

Cartilaginous

Costal cartilage • Bound together by with end of rib periosteum • Little if any movement permitted

Intervertebral

Symphysis

Adjacent verte- Strengthened by bral bodies anterior and posterior longitudinal ligaments and the anular ligament (continued)

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Joints of the thoracic wall (continued) Joint Costovertebral

Type Synovial

Costotransverse

Articulation Structure Head of ribs with • Strengthened by vertebral bodies radiate and intraat same level articular ligaments and the • 1st, 11th, 12th, and vertebral body and sometimes 10th superior to it ribs articulate only with vertebral body of same level Tubercle of rib • Strengthened by with transverse lateral and superior process of costotransverse vertebral body ligaments at same level • 11th and 12th ribs do not participate in costotransverse joints

BREAST The breast extends from the sternum to the midaxillary line and from ribs 2–6. It rests on the pectoral fascia and the fascia over serratus anterior. Structure of the breast (Figure 1-3) Structure Mammary glands

Areola

Nipple

Description Significance • Modified sweat glands • Accessory reproductive • Arranged in 15–20 lobules organs in the female • Contained within the breast • The skin around the nipple • Turns a darker color • Studded with sebaceous during pregnancy glands that form eleva• Stimulation from the tions suckling infant triggers ejection and production of milk—the let-down reflex • Round, raised area of skin Stimulation from the suckling in the center of the areola infant triggers erection of • Surrounded by circularly the nipple and the ejection arranged smooth muscle and production of milk fibers that cause erection on stimulation (continued)

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Structure of the breast (continued) Structure

Description

Suspensory ligaments

Connective tissue supports • Provide support for the that extend from the dermis breast to the pectoral fascia • If invaded by carcinoma, the ligaments shorten and produce skin dimpling and nipple inversion

Significance

Lactiferous duct 15–20 total, open onto the nipple

Drain the mammary glandular tissue

Lactiferous sinus Expansion of lactiferous duct near the nipple

Function as a milk reservoir during lactation

Axillary process Extension of breast tissue into the axilla

High percentage of breast tumors occurs here

Axillary tail

Serratus anterior External abdominal oblique

Areola Nipple Lobes

Lactiferous ducts Fat

Lactiferous sinus

FIGURE 1-3. Breast, anterior view. (From Tank PW, Gest TR. LWW Atlas of Anatomy. Baltimore: Lippincott Williams & Wilkins; 2009:39.)

Additional Concept The size and shape of the adult female breast is due to its contained fat, which forms the bulk of the breast tissue.

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Clinical Significance Quadrants The breast is divided into four quadrants for the anatomic location and description of pathologies. The inferior quadrants are less vascular and, therefore, the preferred area for surgical incisions when necessary. Retromammary Space Between the breast and the pectoral fascia is the retromammary space, which permits movement of the breast on the thoracic wall. Diminishment of this movement may indicate pathology. Nerves of the breast Nerve

Origin

Anterior cutaneous Intercostal branches nerves 4–6 Lateral cutaneous branches

Structures Innervated • Sensory to skin of breast • Postsynaptic sympathetic fibers to the smooth muscle of the nipple and blood vessels

Arterial supply of the breast Artery

Origin

Description

Medial mammary branches

Internal thoracic

Supplies medial aspect of breast

Lateral mammary branches

Lateral thoracic

Supplies lateral aspect of breast

Thoracoacromial

Axillary

Supplies breast through pectoral branches

Posterior intercostals

Thoracic aorta

Supplies lateral aspect of breast through lateral mammary branches

Anterior intercostals

Additional Concept Venous drainage of the breast parallels the arterial supply and drains mainly to the axillary vein, whereas some venous drainage is to the internal thoracic vein.

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Lymphatics of the breast Knowledge of the lymphatic drainage of the breast is important owing to the high incidence of breast carcinoma. Lymphatic Structure Subareolar lymphatic plexus Axillary lymph nodes Parasternal lymph nodes

Description Located deep to the nipple, areola, and around the lobules of the glandular tissue of the breast Composed of pectoral, humeral, subscapular, central, and apical nodes Located along the sternum

Abdominal lymph nodes

Drainage Drains lymph from the nipple, areola, and glandular tissue of the breast to regional nodes Drains ⬃75% of lymph from the breast—the lateral quadrant in particular Drains mostly lymph from the medial quadrant of the breast Drains mostly lymph from the inferior quadrants of the breast

Located inferior to the diaphragm in the abdominal cavity; also known as inferior phrenic lymph nodes Infraclavicular Located inferior to the Drains lymph from the axillary lymph nodes clavicle lymph nodes SupraclaviLocated superior to the cular lymph clavicle nodes Subclavian Formed from efferent vessels • On the right—joins with lymphatic of the axillary nodes, apical bronchomediastinal & trunk in particular jugular trunks to form the right lymphatic duct • On the left—joins the thoracic duct

Additional Concept The contralateral breast receives a significant amount of lymphatic drainage.

MISCELLANEOUS Thoracic cavity The thoracic cavity is bounded by the thoracic wall—a flexible musculoskeletal cage. It is divided into 2 laterally placed pleural cavities and a central region—the mediastinum. The thoracic cavity contains the heart, lungs, thymus, trachea, esophagus, and multiple neurovascular elements.

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Thoracic cavity (continued) Area Superior thoracic aperture

Structure Boundaries: • Anterior—manubrium • Posterior—T1 • Lateral—1st ribs and their costal cartilages

Inferior thoracic aperture

Boundaries: • Anterior—xiphisternal joint • Anterolateral—costal cartilages of ribs 7–10— the costal margin • Posterior—T12 • Posterolateral—11th and 12th ribs Space between adjacent ribs Contains intercostal muscles and costal cartilages and intercostal neurovascular elements • Superior border—superior Contains superior vena cava, thoracic aperture brachiocephalic veins, arch of • Inferior border—plane aorta, thoracic duct, esophagus, passing from sternal angle trachea, left & right vagus through the T4–T5 nerves, left recurrent laryngeal vertebral level nerve and left & right phrenic • Lateral borders—pleural nerves, and the thymus cavities • Superior border—plane Subdivided by the pericardial passing from sternal angle sac into anterior, middle, and through the T4–T5 posterior mediastina vertebral level • Inferior border—diaphragm • Lateral borders—pleural cavities • Most anterior part of the Contains the thymus, loose inferior mediastinum connective tissue, sternoperi• Bounded anteriorly by the cardial ligaments, lymph sternum and transverse nodes, and fat thoracic muscle and posteriorly by the pericardium Middle part of inferior Contains the heart, pericardial mediastinum sac, roots of the great vessels, arch of the azygos vein, and primary bronchi Most posterior part of the Contains the thoracic aorta, inferior mediastinum esophagus, azygos and hemiazygos veins, vagus nerves, thoracic duct, sympathetic trunks, and splanchnic nerves

Intercostal space Superior mediastinum

Inferior mediastinum

Anterior mediastinum

Middle mediastinum

Posterior mediastinum

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Significance • Also known as the thoracic inlet • Allows passage of the trachea, esophagus, and neurovascular elements between the thoracic cavity and the neck • Also known as the thoracic outlet • Closed by the diaphragm • Allows for passage of the inferior vena cava, aorta, and esophagus between the thoracic cavity and abdomen

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Mnemonic V-A-N: Intercostal neurovascular elements are arranged from superior to inferior as: intercostal Vein intercostal Artery intercostal Nerve

Clinical Significance Thoracic Outlet Syndrome Obstructions in the root of the neck may affect structures passing through the superior thoracic aperture; problems are often manifested in the upper limb. Posterior mediastinum Structure

Significance

Organ Esophagus

• Located posterior to the trachea, anterior to vertebral bodies • Begins at inferior aspect of pharynx (C6) • Terminates by entering the stomach after passing through the esophageal hiatus (T10) of the diaphragm

Nerve Esophageal • Formed of parasympathetic fibers from the vagus nerves and plexus sympathetic fibers from sympathetic chain ganglia and the greater splanchnic nerve • Supply glands and musculature of inferior 2/3 of esophagus Sympathetic • Located on either side of the vertebral column along posterior trunks wall of the thorax • Chain of paravertebral ganglia containing presynaptic sympathetic cell bodies • Ganglia connected by presynaptic sympathetic and visceral afferent fibers • Connected to thoracic spinal nerves by rami communicantes Thoracic splanchnic nerves

• Greater, lesser, and least • Convey presynaptic sympathetic fibers from T5–T12 to prevertebral ganglia of the abdomen • Convey visceral afferents from the abdomen

Vessel Thoracic aorta

• Continuation of the arch of the aorta; becomes abdominal aorta after passing through the aortic hiatus (T12) of the diaphragm • Found to the left of thoracic vertebral bodies (continued)

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Posterior mediastinum (continued) Structure Bronchial arteries Pericardial arteries Posterior intercostal arteries—9 pairs Superior phrenic arteries Esophageal arteries Subcostal arteries Thoracic duct

Significance • Left: branches of thoracic aorta • Right: branches of posterior intercostal arteries • Supply oxygenated blood to the tissues of the lung • Branches of thoracic aorta and pericardiophrenic arteries • Supply the pericardium • Branches of thoracic aorta • Supply intercostal spaces 3–11

• Branches of the thoracic aorta • Supply the diaphragm

• Branches of the thoracic aorta • Supply the esophagus • Branches of the thoracic aorta • Supply body wall inferior to the 12th ribs • Conveys lymph from entire body, except the right upper limb, right aspect of the thorax and right side of head & neck • Begins in abdomen at chyle cistern and empties into the junction of left internal jugular vein and left subclavian vein • Found along the vertebral column between the azygos vein and esophagus Azygos vein • Drains mediastinum and posterior thoracic & abdominal walls on the right; found on right side of vertebral bodies • Begins in the abdomen and terminates by emptying into superior vena cava • Receives hemiazygos and accessory hemiazygos veins at the T8–T9 vertebral level Hemiazygos • Drains mediastinum and posterior thoracic and abdominal vein walls on the left as high as T9 vertebral level, where it crosses to the right side to enter the azygos vein Accessory • Drains mediastinum and posterior upper thoracic wall on the hemiazygos left as far inferiorly as T8 vertebral level where it crosses to vein the right side to enter the azygos vein

The trachea is presented with the superior mediastinum.

Clinical Significance Esophageal Constrictions Three constrictions of the esophagus occur where it is compressed by, from superior to inferior: (1) arch of the aorta, (2) left main bronchus, and (3) the diaphragm. These constrictions are areas susceptible to damage from swallowing caustic substances and are places where ingested objects

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Esophagus Trachea Sympathetic chain

Azygos vein Right primary bronchus

Intercostal vein, artery, and nerve

Left primary bronchus Thoracic duct Diaphragm

Cut edge of costal pleura

FIGURE 1-4. Posterior mediastinum viewed from the right: parietal pleura is intact on left side and partially removed on right. A portion of esophagus, between bifurcation of trachea and diaphragm, is also removed. (From Agur AMR, Dalley AF. Grant’s Atlas of Anatomy, 12th ed. Baltimore: Lippincott Williams & Wilkins; 2009:82.)

may become lodged; the constrictions are visible on radiographs and are useful landmarks. Azygos Veins The azygos system provides a collateral pathway for venous blood that connects the superior and inferior vena cavae. Mnemonic Four birds of the thorax: esophaGOOSE vaGOOSE nerve azyGOOSE vein thoracic DUCK

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Superior mediastinum (Figure 1-5) Structure Significance Ligamentum • Remnant of the ductus arteriosus (shunt for blood from the arteriosum fetal pulmonary trunk to aorta) • Connects left pulmonary artery to the arch of the aorta • Left recurrent laryngeal nerve wraps around to then ascend to the larynx Organ Thymus • Located mostly in the superior mediastinum • Lymphatic organ that involutes after puberty and is replaced by fat Trachea • Located anterior to the esophagus • Begins at cricoid cartilage of the larynx • Terminates at the level of the sternal angle into 2 main bronchi • Skeleton of posteriorly oriented U-shaped rings, posterior deficiency spanned by the trachealis muscle Esophagus • Located posterior to the trachea and anterior to the vertebral bodies • Begins at inferior aspect of the pharynx, terminates by entering the stomach after passing through the esophageal hiatus (T10) of the diaphragm Nerve Left vagus • Found anterior to the arch of the aorta where it gives off the left recurrent laryngeal nerve • Passes posterior to the root of the lung, where it ramifies to contribute to the pulmonary, cardiac, and esophageal plexuses Right vagus • Found anterior to the right subclavian artery, where it gives off the right recurrent laryngeal nerve • Passes posterior to the root of the lung, where it ramifies to contribute to the pulmonary, cardiac, and esophageal plexuses Left • Branch of left vagus nerve as it passes over the anterior recurrent surface of the arch of the aorta laryngeal • Ascends to the larynx between the trachea and esophagus Right • Branch of the right vagus nerve as it passes over the anterior recurrent surface of the right subclavian artery laryngeal • Ascends to the larynx between the trachea and esophagus in the tracheoesophageal groove Left phrenic • Passes anterior to the root of the lung, found between the nerve fibrous pericardium and mediastinal pleura Right • Sole motor supply to the diaphragm phrenic • Sensory to central aspects of diaphragm nerve (continued)

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Superior mediastinum (continued) Structure Vessel

Significance

Left brachiocephalic vein

• Formed by junction of the internal jugular and subclavian veins • The left and right brachiocephalic veins join to form the superior vena cava

Right brachiocephalic vein Superior vena cava Arch of the aorta

Drains most venous blood from structures superior to the thorax into the right atrium • Continuation of the ascending aorta; becomes the thoracic aorta as it descends • Gives off 3 branches in the superior mediastinum: 1. brachiocephalic trunk 2. left common carotid artery 3. left subclavian artery • Left vagus nerve courses on its anterior surface

Brachioce- • 1st branch of the arch of the aorta phalic trunk • Terminates by dividing into the right common carotid and right subclavian arteries • Indirectly supplies the right side of head and neck and right upper limb through its branches Left common carotid artery

• 2nd branch of the arch of the aorta • Terminates in the neck by dividing into internal & external carotid arteries • Indirectly supplies left side of head and neck through its branches

Left subclavian artery

• 3rd branch of the arch of the aorta • Continues as it passes over the lateral border of the 1st rib to become the left axillary artery • Supplies the left upper limb

The thoracic duct is presented with the posterior mediastinum.

Additional Concept Lymphatic Drainage In addition to the brachiocephalic veins forming at the junction of the internal jugular and subclavian veins, it is also the point where the right lymphatic duct joins the venous system on the right and the thoracic duct on the left—known as the jugular angle.

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Structure of the pericardial cavity (Figure 1-5) Structure Pericardial sac

Description Formed of 2 layers: 1. outer—fibrous pericardium 2. inner—parietal layer of serous pericardium

Visceral layer of serous pericardium Parietal layer of serous pericardium Pericardial cavity

Mesothelium—simple squamous epithelium

Fibrous pericardium

Transverse sinus Oblique sinus

Potential space between the layers of serous pericardium • Strong collagenous outer layer of the pericardial sac • Fuses with adventitia of great vessels, central tendon of the diaphragm, and sternum Extension of the pericardial cavity posterior to the pulmonary trunk and aorta Extension of the pericardial cavity on the posterior aspect of the heart

Significance • Double-layered fibroserous sac that encloses the heart • Fused with adventitia of the great vessels • Attached to the deep surface of the sternum by the sternopericardial ligament • Fuses with the central tendon of the diaphragm; therefore, moves during respiration Also known as the epicardium—the outer layer of the heart Lines inner surface of fibrous pericardium • Filled with serous fluid • Allows heart to beat in a friction free environment • Inflexible nature prevents overfilling of the heart • Phrenic nerve travels inferiorly through the thorax on its lateral surface

Allows for control of blood out of the heart during surgery Ends as a cul-de-sac between the pulmonary veins

MEDIASTINUM Additional Concept Pericardium The pericardium receives its arterial supply from the pericardiacophrenic arteries, which run with the phrenic nerve between the mediastinal pleura and the fibrous pericardium. Sensory innervation to the pericardium is carried via the phrenic nerves.

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Clinical Significance Pericarditis Inflammation of the pericardium that may cause chest pain and pericardial friction rub, which can be detected during auscultation. Pericardial Tamponade An increase in fluid in the pericardial cavity (e.g., from chronic inflammation) may decrease the efficiency of the heart as it is compressed. Pericardiocentesis is the drainage of excess fluid from the pericardial sac. Structure of the heart (Figure 1-6) The heart is contained within the pericardial sac. It is located within the middle mediastinum, left of the median plane in the thorax. The heart is essentially a cone-shaped muscular pump, the apex of which is directed anteroinferiorly to the left and the base posterolaterally to the right. The base of the heart is the location of the superior vena cava, ascending aorta and pulmonary trunk. Structure Heart surfaces

Description • Anterior (sternocostal) • Inferior (diaphragmatic) • Right and left pulmonary surfaces

Pectinate muscles

Muscular ridges found on the walls of the atria

Trabeculae carneae

Muscular ridges found on the walls of the ventricles

Significance • Anterior—formed mainly by right ventricle • Diaphragmatic—formed mainly by left ventricle (some right ventricle) related to central tendon of diaphragm • Left pulmonary—formed mainly by left ventricle, related to cardiac notch of left lung • Right pulmonary—formed mainly by right atrium • Found in primitive parts of both atria • Presence indicates “rough” part of atrial walls • Found in primitive parts of both ventricles • Serve to increase mechanical advantage during ventricular contraction • Presence indicates “rough” part of ventricular walls (continued)

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Structure of the heart (continued) Structure Papillary muscles

Description Conical muscular projections from the ventricular wall that attach to chordae tendineae

Significance Contract immediately before ventricular contraction to pull chordae tendineae taut to prevent backflow during ventricular contraction (systole) Chordae Attached to margins of Hold valve cusps taut during tendineae atrioventricular valves and ventricular contraction to papillary muscles prevent backflow (regurgitation) Interatrial Muscular septum separating Right side—location of fossa septum the atria ovalis: remnant of foramen ovale, an embryologic shunt for blood from the right atrium to the left atrium Interventricular Composed of a membranous Separates right and left septum (superior) part and a muscular ventricles (inferior) part Right and • Right—3 cusps • Right—permits passage of left atrioventri- (tricuspid) blood from right atrium to cular valves • Left—2 cusps right ventricle and prevents (bicuspid, mitral) backflow in the reverse direction • Left—permits passage of blood from left atrium to left ventricle and prevents backflow in the reverse direction Fibrous • Collagenous skeleton of • Provides stability and attachskeleton heart ment for valve cusps and • Forms fibrous rings that muscle fibers surround heart orifices • Provides electrical insulation • Fibrous trigones connect between the atria and rings ventricles Right atrium Forms right border of heart Receives deoxygenated blood from the superior and inferior vena cavae & coronary sinus Sinus venarum Smooth-walled part of right Formed from incorporation of atrium the embryonic sinus venosus during development Sulcus Groove on outside of right External representation of terminalis atrium meeting of primitive atrium and sinus venarum derived tissues Crista Ridge on inside of right Internal representation of terminalis atrium meeting of primitive atrium and sinus venarum derived tissues (continued)

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Structure of the heart (continued) Structure Right auricle Left atrium Left auricle

Description Small, conical projection from right atrium Forms most of base of heart Finger-like projection from left atrium Forms inferior border of heart Smooth-walled superior aspect of right ventricle

Significance Remnant of primitive right atrium Receives oxygenated blood from 4 pulmonary veins Remnant of primitive left atrium Receives blood from right atrium Entry to the pulmonary trunk

Right ventricle Conus arteriosus (infundibulum) SupraventriMuscular ridge on inside of Separates rough part of cular crest right ventricle chamber from smooth-walled part of chamber Septomarginal Muscular ridge that extends Conveys right atrioventricular trabecula from the inferior aspect of bundle—part of conduction (moderator the interventricular septum system, to the anterior band) to the base of the anterior- papillary muscle most papillary muscle Pulmonary • 3 semilunar cusps Prevents backflow valve • Located at apex of conus (regurgitation) of blood during arteriosus ventricular relaxation (diastole) Pulmonary Located between cup-shaped Prevent valve cusps from sinuses semilunar valve leaflets and sticking to pulmonary trunk dilated pulmonary trunk wall wall during ventricular contraction Left ventricle Forms apex and left border Thicker wall (4⫻) than right of heart ventricle because it pumps against greater pressure Aortic vestiSmooth-walled superior Entry to ascending aorta bule aspect of left ventricle Aortic valve • 3 semilunar cusps Prevent backflow • Located near origin of (regurgitation) of blood during ascending aorta ventricular relaxation (diastole) Aortic sinuses Located between cup• Prevent valve cusps from shaped semilunar valve sticking to ascending aorta leaflets and dilated ascendwall during ventricular ing aorta wall contraction • Right and left sinus give origin to the right and left coronary arteries respectively

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Right brachiocephalic vein Left brachiocephalic vein

Left subclavian artery Left common carotid artery Brachiocephalic trunk

Superior vena cava

Arch of aorta Ligamentum arteriosum

Reflection of pericardium

Pulmonary trunk Conus arteriosus Left auricle

Right auricle Pectinate muscles Fossa ovalis Right atrium Right coronary artery Tricuspid valve Papillary muscle Inferior vena cava

Abdominal aorta

Anterior interventricular artery Left ventricle Chordae tendineae Muscular interventricular septum Apex of heart Moderator band

FIGURE 1-5. Heart. Right interior view. (Asset provided by Anatomical Chart Company.)

Additional Concept Heart is a “Double Pump” Right side of the heart: right atrium receives deoxygenated blood from the vena cavae; the right ventricle pumps this blood to the lungs for oxygenation via the pulmonary trunk. Left side of the heart: left atrium receives oxygenated blood from the pulmonary veins; the left ventricle pumps this blood to the body via the aorta. Walls of the Heart The walls of all 4 chambers of the heart consist of the same three layers from superficial to deep: epicardium—layer of mesothelium; also known as visceral layer of serous pericardium myocardium—middle layer composed of cardiac muscle tissue endocardium—layer of endothelium that lines heart chambers and valves

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Auscultation Auscultation of the valves: each of the 4 valves of the heart is heard best at specific locations on the thoracic wall: bicuspid valve—5th intercostal space on the left tricuspid valve—4th intercostal space to the left of the sternum pulmonary valve—2nd intercostal space to the left of the sternum aortic valve—2nd intercostal space to the right of the sternum Ventricles Ventricle characteristics—fewer, larger papillary muscles, more numerous trabeculae carneae, fewer, thicker atrioventricular valve cusps and fewer, thicker chordae tendineae are characteristics of the left ventricle owing to its increased workload relative to the right ventricle.

Clinical Significance Foramen Ovale Incomplete closure of the foramen ovale occurs in 15%–25% of adults, it is typically asymptomatic. Septal Defects The membranous part of the interventricular septum is the most common site of interventricular septal defects; severe defects may result in hypertension and cardiac failure. Nerves of the heart Nerve Superficial cardiac plexus

Origin Structures Innervated • Sympathetic— • Sympathetic—terminate on SA and sympathetic AV nodes, increases heart rate and trunks force of contraction, produces vasodi• Parasymlation of coronary arteries pathetic—vagus • Parasympathetic—terminate on SA nerves and AV nodes and coronary arteries, • Located inferior decreases heart rate and force of to the aortic arch contraction, causes vasoconstriction and anterior to of coronary arteries the right pulmonary artery (continued)

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Nerves of the heart (continued) Nerve Deep cardiac plexus

Origin Structures Innervated • Sympathetic— sympathetic trunks • Parasympathetic—vagus nerves • Located posterior to the aortic arch and anterior to the tracheal bifurcation Visceral Fibers travel with • Fibers traveling with sympathetics afferents of sympathetics and convey pain information to T1–T5 cardiac plexuses in the vagus nerve spinal cord segments; these fibers are involved in pain referred to the left upper limb during heart attack • Fibers traveling in the vagus nerve innervate baroreceptors and chemoreceptors that monitor pressure and gas concentrations in the blood Sinuatrial (SA) Group of selfPacemaker of the heart, gives an node excitable cardiac impulse ~70 times per minute muscle cells located near the junction of the superior vena cava and the right atrium Atrioventricular Located on the • Receives impulse from wall of atria (AV) node right side of the that was initiated in the SA node atrial septum near • Passes impulse to ventricles via the the opening of the AV bundle coronary sinus AV bundle Fiber bundle pass- Only bridge of conduction system (Bundle of His) ing from the AV between atria and ventricles node to membranous part of interventricular septum, where it terminates by dividing into bundle branches Right and left Formed by termina- • Supply cardiac muscle cells of bundle branches tion of AV bundle, ventricular walls through ramifications follow interventri(subendocardial branches) cular septum to • Right bundle branch sends a branch ventricular walls through the septomarginal trabeculae where they ramify of the right ventricle to the anterior papillary muscle

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Additional Concept Postsynaptic parasympathetic ganglia are located near the SA and AV nodes. Vessels of the heart Artery Right coronary

SA nodal branch Right marginal branch Posterior interventricular AV nodal branch Left coronary Anterior interventricular (left anterior descending Left circumflex branch Left marginal branch Posterior interventricular branch Vein Coronary sinus

Great cardiac

Middle cardiac Small cardiac Oblique vein of left atrium Left posterior ventricular Left marginal Anterior cardiac Smallest cardiac

Origin Right aortic sinus

Description Supplies right atrium & ventricle, left ventricle, SA and AV nodes, and interventricular septum Right coronary Supplies SA node artery Supplies right ventricle and apex of heart Supplies both ventricles and posterior aspect of interventricular septum Supplies AV node Left aortic sinus Supplies left atrium and ventricle, right ventricle, and interventricular septum Left coronary Supplies right and left ventricles and artery interventricular septum Supplies left atrium and ventricle Left circumflex branch Left coronary artery Termination Right atrium

Supplies left ventricle Supplies interventricular septum

Description Large vein on posterior aspect of heart in coronary sulcus; accepts most venous blood from the heart before emptying into right atrium Coronary sinus Runs with anterior interventricular artery in anterior interventricular sulcus; becomes coronary sinus on posterior aspect of heart Runs with posterior interventricular artery in posterior interventricular sulcus Runs with right marginal branch Remnant of primordial left superior vena cava Drains posterior aspect of left ventricle

Right atrium Chambers of heart

Drains left margin of heart Drains right ventricle Drains walls of all 4 chambers of heart

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Additional Concept Venous Drainage Venous drainage of the heart is said to be “indirect” because most venous blood enters the coronary sinus before being emptied into the right atrium.

Clinical Significance Coronary Arteries Coronary artery disease is a leading cause of death, typically as a result of decreased blood flow to the heart. An area of myocardium that has undergone necrosis (as a result of lack of blood) constitutes a myocardial infarction or heart attack.

LUNGS AND PLEURA Structure of the pleural cavities (Figures 1-4, 1-6 and 1-7) Structure Endothoracic fascia

Costal pleura

Mediastinal pleura

Diaphragmatic pleura

Cervical pleura

Pulmonary ligament

Description Fibroareolar layer between parietal pleura and thoracic wall

Significance Invests muscular and skeletal elements of thoracic wall and adheres parietal pleura to inner surface of thoracic wall Parietal pleura adherent to Intercostal and phrenic nerves the inner surface of the ribs provide sensory innervation; and costal cartilages via the therefore, pain may be referred endothoracic fascia to the thoracic wall and neck Parietal pleura adherent to the outer surface of the mediastinum via the endothoracic fascia Parietal pleura adherent to the superior surface of the diaphragm via the endothoracic fascia • Parietal pleura extending into the root of the neck • Covered by the suprapleural membrane—a regional thickening of the endothoracic fascia Double-layered fold of pleura Area of reflection—visceral extending inferiorly from the pleura from the surface of root of the lung the lung is continuous with parietal pleura (continued)

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Structure of the pleural cavities (continued) Structure

Description

Significance

Visceral pleura

Covers all surfaces of each lung

• Continuous with parietal pleura at the root of the lung • No or very limited pain afferents

Pleural cavity

Potential space between the • Contains capillary layer of visceral and parietal pleura serous fluid • Negative pressure here maintains lungs in inflated state

Left and right costodiaphragmatic recesses

Potential space between costal and diaphragmatic pleura

During inspiration the lungs enter the recesses

Left and right Potential spaces between costomediastinal costal and mediastinal recess pleura

Superior vena cava

Right atrium

Pulmonary trunk

Left ventricle

IVC and pericardium Pericardium

FIGURE 1-6. Anteroposterior chest radiograph. Radiograph shows the various components of the heart and great vessels. (From Dudek RW, Louis TM. High-Yield Gross Anatomy. 3rd ed. Baltimore: Lippincott Williams & Wilkins; 2008:85.)

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FIGURE 1-7. Pneumothorax. A pneumothorax is air in the plural cavity; this has the effect of collapsing the elastic lung as the negative pressure maintaining it in its expanded state is lost. Posteroanterior radiograph shows a left apical (straight arrows) and subpulmonic (curved arrow) pneumothorax in a 41-year-old woman with respiratory distress syndrome. (From Dudek RW, Louis TM. High-Yield Gross Anatomy. 3rd ed. Baltimore: Lippincott Williams & Wilkins; 2008:64.)

Clinical Significance Cervical Pleura The cervical pleura and apex of the lung are subject to injury from neck wounds because the pleural cavity extends into the root of the neck. Tracheobronchial tree (Figure 1-4) Structure

Description

Significance

Tracheal rings

20 U-shaped hyaline cartilages

• Keep trachea patent • Posteriorly oriented opening of U-shaped cartilage allows for expansion of the esophagus during swallowing (continued)

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Tracheobronchial tree (continued) Structure

Description

Significance

Trachealis

Layer of smooth muscle

Spans posterior deficiency of tracheal rings

Right and left main bronchi

• Extend from tracheal bifurcation to hilum of lungs • Supported by U-shaped hyaline cartilage • Terminate by dividing into lobar bronchi

• Form part of root of the lung • Enter lung at hilum • Right main bronchus is shorter, wider and more vertically oriented than the left • Hyaline cartilage keeps both main bronchi patent

Carina

Keel-like septum projecting superiorly at the bifurcation of the trachea

Visible on radiographs; displacement may indicate thoracic pathology

Lobar (secondary) • Supported by hyaline bronchi (3; right) cartilage

• Hyaline cartilage keeps lobar bronchi patent

Lobar (secondary) • Extend from main bronchi until termination as segbronchi (2; left) mental bronchi

• Each lobar bronchus corresponds to a lobe of the lung

Segmental • Supported by hyaline (tertiary) bronchi cartilage • Formed from terminal branches of lobar bronchi

• Supply bronchopulmonary segments—right lung: 10 segmental bronchi • Left lung: 8–10 segmental bronchi

Bronchopulmonary segments

Pyramidal-shaped with • Each receives a segmental apex directed toward root of bronchus and a branch of lung and base toward outer both pulmonary and surface of lung bronchial arteries • Intersegmental veins help identify boundaries between segments for resection

Additional Concept Bronchopulmonary Segments ■

■

Right lung—Superior lobe: Apical, Posterior, Anterior Middle lobe: Lateral, Medial Inferior lobe: Superior, Anterior basal, Posterior basal, Lateral basal, Medial basal Left lung—Superior lobe: Superior division—Apicoposterior, Anterior; Lingular division—Superior, Inferior Inferior lobe: superior, Anterior basal, posterior basal, Lateral basal, Medial basal

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Mnemonic Inhale a Bite, Goes Down the Right Inhaled objects more likely to enter right bronchus, as it is wider, shorter, and more vertical than the left. Structure of the lungs The lungs are the elastic organs of respiration. Their function depends upon surface tension in the pleural cavity keeping the parietal and visceral layers of pleura together. Structure

Description

Significance

Right lung

3 lobes (superior, middle, and inferior) separated by a horizontal and oblique fissure

The right lung is larger than the left

Left lung

2 lobes (superior and inferior) The left lung is smaller than separated by an oblique the right owing to the position fissure of the heart

Cardiac notch

Indentation of superior lobe of left lung along the anteroinferior border

Lingula

Tongue-like process of superior lobe of the left lung inferior to the cardiac notch

Root of lung

• Formed by pulmonary and bronchial arteries, pulmonary and bronchial veins, lymphatics, nerves, and main bronchi • Enclosed by pleural sleeve

Hilum of lung

Located on medial aspect of Root of lung enters lung here lungs

Result of the heart and pericardial sac bulging to the left

Located on medial aspect of lung, site at which structures enter and leave the lung

Horizontal and • Right lung has 1 horizontal Separate lungs into lobes: oblique fissures and 1 oblique fissure right lung 3, left lung 2 • Left lung has 1 oblique fissure

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Nerves of the lungs Nerve

Origin

Structures Innervated

Anterior • Sympathetic— • Sympathetic—inhibit bronchial pulmonary plexus sympathetic smooth muscle (bronchodilate) and trunks glands, motor to vessels • Parasym(vasoconstrict) pathetic—vagus • Parasympathetic—inhibit vessel nerves musculature (vasodilate), motor to • Located anterior smooth muscle of bronchial tree to root of lung (bronchoconstrict) and glands (stimulates mucous secretion) Posterior • Sympathetic— pulmonary plexus sympathetic trunks • Parasympathetic—vagus nerves • Located posterior to root of lung Visceral afferents Fibers travel in of pulmonary vagus nerve plexuses

Sensory to tissues of the lungs and bronchi—touch, stretch, temperature, and chemical irritants

Additional Concept Postsynaptic parasympathetic ganglia are found distributed throughout both plexuses. Vessels of the lungs Artery

Origin

Description

Right and left pulmonary

Pulmonary trunk

Give rise to lobar arteries; carry deoxygenated blood to the lungs

Lobar

Pulmonary arteries

3 right and 2 left lobar arteries carry deoxygenated blood to each lobe of the lung; accompany secondary bronchi

Right and left bronchial

• Right— posterior intercostal artery • Left— thoracic aorta Termination Left atrium

Supply oxygenated blood to the tissues of the bronchial tree

Vein Right and left pulmonary

Description 2 pairs of pulmonary veins convey oxygenated blood to the left atrium (continued)

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Vessels of the lungs (continued) Vein

Termination

Right and left bronchial

• Right— Drain deoxygenated blood from the azygos vein bronchial tree • Left— accessory hemiazygos vein

Description

Additional Concept Ligamentum Arteriosum The ligamentum arteriosum is the remnant of the ductus arteriosus—an embryologic shunt connecting the arch of the aorta and the left pulmonary artery. Lymphatics of the lungs Lymphatic structure

Description

Drainage

Superficial Located immediately deep to Drains to bronchopulmonary lymphatic plexus visceral pleura lymph nodes Deep lymphatic plexus

Located in the submucosa of Drains to pulmonary lymph bronchi and connective nodes tissue around the bronchi

Pulmonary lymph nodes

Located along the lobar (secondary) bronchi

Drain to bronchopulmonary lymph nodes

Bronchopulmonary (hilar) lymph nodes

Located in the hilum of the lung(s)

Drain to tracheobronchial lymph nodes

Superior and Located at the bifurcation of Drain to bronchomediastinal inferior tracheo- the trachea trunks (right and left) bronchial lymph nodes

Additional Concept The superficial and deep lymphatic plexuses of the lungs communicate freely.

Clinical Significance Bronchopulmonary nodes are an early site of tumor metastases in bronchogenic carcinoma.

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Abdomen

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INTRODUCTION The abdomen is that portion of the trunk inferior to the diaphragm and superior to the pelvis with which it is continuous. The abdomen extends inferiorly to the superior pelvic aperture.

AREAS AND FASCIA OF THE ABDOMEN Areas of the abdomen Area Abdominal cavity

Regions (9)

Structure Boundaries: • Superior— diaphragm • Inferior— continuous with pelvic cavity at superior pelvic aperture • Anterolateral— muscular abdominal wall • Posterior— vertebral column Divided into regions by: • 2 horizontal planes—subcostal and transtubercular • 2 verticalmidclavicular planes

Significance Larger, superior part of the abdominopelvic cavity

• Regions: • Right and left hypochondriac • Right and left inguinal • Right and left lateral • Epigastric • Umbilical • Pubic • Used for description of organ location or location of pathologic processes (continued)

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Areas of the abdomen (continued) Area Quadrants (4)

Inguinal canal

Subinguinal space

Structure Divided into quadrants by a horizontal (transumbilical) and a vertical (median) plane • 4–6 cm long, inferomedially directed passage extending between the deep and superficial inguinal rings • Walls of canal: • Anterior— external oblique aponeurosis • Posterior— transversalis fascia and medially the conjoint tendon • Roof— transversalis fascia and arching fibers of the internal oblique and transversus abdominis • Floor—iliopubic tract, inguinal ligament, and lacunar ligament from lateral to medial Space located deep to the inguinal ligament and iliopubic tract

Significance • Quadrants: • Right and left upper • Right and left lower • Used for description of organ location or location of pathologic processes • Transmits the spermatic cord or round ligament of the uterus, ilioinguinal nerve, and the genital branch of the genitofemoral nerve • One result of the oblique nature of canal is that the superficial and deep rings do not overlap; therefore, increases in intraabdominal pressure force the canal “closed” to prevent herniation

Serves to connect the abdominopelvic cavity with the lower limb

Additional Concepts Deep Inguinal Ring The deep inguinal ring, the internal opening of the inguinal canal, is an evagination of transversalis fascia, just superior to the middle of the inguinal ligament and immediately lateral to the inferior epigastric vessels.

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Superficial Inguinal Ring The superficial inguinal ring is the slitlike external opening of the inguinal canal in the aponeurosis of the external oblique muscle, just superior to the public tubercle. The medial and lateral margins of the opening are the medial and lateral crura, which are prevented from spreading apart by intercrural fibers. Structures of the abdominal wall Feature Superficial fascia

Description Inferior to umbilicus, it is composed of 2 layers: • A superficial fatty layer (Camper’s fascia) • A deep membranous layer (Scarpa’s fascia)

Investing fascia

Covers the muscles (4) forming the muscular wall of the abdomen • Lines inner surface of abdominal wall • Named according to muscle it lines: • Transversalis fascia lines the transverse abdominal muscle • Divided into anterior, middle, and posterior layers • Middle and posterior layers enclose the intrinsic muscles of the back—relatively thick, provides attachment for anterolateral abdominal wall muscles • Anterior layer is fascia of quadratus lumborum muscle—thickened superiorly to form lateral arcuate ligament, inferiorly attaches to iliolumbar ligament • Lumbar fascia lines the quadratus lumborum • Psoas fascia lines the psoas major muscle • It is thickened superiorly to form the medial arcuate ligament • It is continuous with the thoracolumbar fascia • Lines abdominopelvic cavity • Located deep to the endoabdominal fascia from which it is separated by extraperitoneal fat • Formed by the aponeuroses of the external and internal oblique and transverse abdominal • The sheath contains the rectus abdominis, the superior and inferior epigastric vessels, the pyramidalis, segmental nerves, and lymphatics

Endoabdominal fascia

Parietal peritoneum

Rectus sheath

(continued)

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Structures of the abdominal wall (continued) Feature

Description

Conjoint tendon

• Fused tendons of internal oblique and transverse abdominal at their attachment to the pubis • Forms medial portion of posterior wall of inguinal canal

Inguinal ligament

• Free, fibrous inferior edge of external oblique, extending between the anterior superior iliac spine and pubic tubercle • Laterally provides attachment for transverse abdominal and internal oblique

Iliopubic tract

• Thickened inferior margin of the transversalis fascia • Forms portion of floor and posterior wall of inguinal canal • Located posterior and parallel to the inguinal ligament • Forms the anterior boundary of the subinguinal space

Lacunar ligament

• Medial-most internally directed portion of the inguinal ligament • Forms portion of floor of inguinal canal • Attaches to superior pubic ramus

Pectineal ligament

Continuation of lacunar ligament as it runs along the pectin pubis

Additional Concept Rectus Sheath Rectus sheath—Above a line midway between the pubic symphysis and umbilicus the anterior layer of the sheath is formed by the external oblique and the anterior portion of the internal oblique, which splits to contribute to the posterior layer of the sheath with the transverse abdominal muscle. Below this line, the sheath is deficient posteriorly, with the aponeurosis of all three muscles forming the anterior layer of the sheath, with only the transversalis fascia separating the rectus abdominis from the parietal peritoneum. The lower edge of the aponeurotic “line” of the posterior sheath is the arcuate line.

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ABDOMINAL WALL Muscles of the abdominal wall Proximal Distal Muscle Attachment Attachment Innervation Anterolateral Abdominal Wall T5–T12 Linea alba, Ribs 5–12 External pubic crest oblique and tubercle, anterior iliac crest Thoracolumbar fascia, anterior iliac crest, inguinal ligament Transverse Costal abdominal cartilages 7–12, thoracolumbar fascia, iliac crest, inguinal ligament Pubic Rectus abdominis symphysis and pubic crest

Ribs 10–12, linea alba, pectin pubis (via conjoint tendon) Linea alba, pubic crest, pectin pubis (via conjoint tendon)

T6–T12 and L1

Xiphoid process, costal cartilages 5–7

T6–T12

Pyramidalis Pubis

Linea alba

T12

Internal oblique

Spermatic Cord and Scrotum Cremaster Found within cremaster fascia Dartos

Found within superficial fascia of scrotum

Posterior Abdominal Wall Pectin pubis T12–L1 Psoas vertebrae and minor intervertebral discs

Main Actions Compress, protect, and support abdominal contents; flex and rotate trunk Compress, protect, and support abdominal contents

Compress, protect, and support abdominal contents; flex trunk (lumbar region) Tenses linea alba

Genitofemoral Autonomic

Draws testes closer to body Wrinkles skin of scrotum

L1

Weak trunk flexor; often absent (continued)

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Muscles of the abdominal wall (continued) Proximal Attachment T12–L5 vertebrae and intervertebral discs Iliac fossa Iliacus Quadratus 12th rib lumborum Muscle Psoas major

Distal Attachment Lesser trochanter of femur

Innervation L2–L4

Iliolumbar ligament and iliac crest

Femoral T12–L4

Main Actions Together form iliopsoas—the chief flexor of the thigh Extends and laterally rotates vertebral column

Skeletal elements (attachments) discussed above are presented with the thorax and pelvis.

Clinical Significance Guarding Reflex In addition to the functions mentioned previously, the flat abdominal wall muscles provide protection to abdominal viscera through involuntary contraction when touched or when an underlying structure is inflamed, becoming rigid; this is known as the “guarding” reflex. Mnemonics Orientation Hands-in-your-pockets orientation: When you put your hands in your pants pockets, your fingers have the orientation of fibers of the external oblique inferomedially. Internal oblique fibers are at right angles to external oblique fibers. Psoas Major Innervation of psoas major: Hitting L2, L3, and L4 makes the psoas sore. Vessels of the abdominal wall Artery Origin Musculophrenic Internal thoracic Superior epigastric Inferior epigastric External iliac

Description Supplies: diaphragm, anterolateral abdominal wall Supplies: rectus abdominis, anterolateral abdominal wall (continued)

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Vessels of the abdominal wall (continued) Artery Superficial epigastric Superficial circumflex iliac Deep circumflex iliac Subcostal Lumbar (4–5 pairs) Testicular Artery of the ductus deferens Cremasteric Vein Pampiniform plexus

Origin Femoral

External iliac Thoracic aorta Abdominal aorta

Inferior vesical artery Inferior epigastric artery Termination Plexus converges to form the testicular veins

Description Supplies: region between umbilicus and pubis Supplies: inguinal region and anterosuperior thigh Supplies: iliacus and anterolateral abdominal wall Supplies: anterolateral abdominal wall Supplies: back and posterior abdominal wall Supplies: testes and epididymis Supplies: ductus deferens Supplies: cremaster muscle and fascia Description Drains the spermatic cord and testes

Additional Concept Abdominal Aorta The abdominal aorta is the continuation of the thoracic aorta after it passes through the aortic hiatus of the diaphragm.The abdominal aorta terminates by dividing into common iliac arteries at L4 vertebral level. The abdominal aorta gives: ■ ■ ■ ■

paired visceral branches: suprarenal, renal, and gonadal unpaired visceral branches: celiac trunk, superior mesenteric and inferior mesenteric arteries paired parietal: inferior phrenic and lumbar unpaired parietal: median sacral artery.

Venous Drainage Veins generally parallel arteries and drain into the inferior vena cava, with the notable exception of the portal system, which drains to the liver. Nerves of the abdominal wall Nerve Origin Thoracoabdominals T7–T11 Subcostal T12

Structures Innervated Anterolateral abdominal wall superior to iliac crest (continued)

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Nerves of the abdominal wall (continued) Nerve

Origin

Structures Innervated

Lumbar Plexus Iliohypogastric

L1

Anterolateral abdominal wall of inguinal and hypogastric regions Scrotum/labia majorum, mons pubis, medial thigh, and lower-most aspect of anterolateral abdominal wall Divides into genital and femoral branches; genital branch supplies cremaster and cutaneous innervation to anterior aspect of scrotum; femoral branch is sensory to anteromedial aspect of thigh Supplies sensory innervation to anterolateral aspect of thigh Supplies adductor compartment of thigh Supplies hip flexors and knee extensors Participates in formation of sacral plexus (L4–S4)

Ilioinguinal

Genitofemoral

L1, L2

Lateral cutaneous nerve of the thigh Obturator Femoral Lumbosacral trunk

L2, L3 L2–L4 L4, L5

Mnemonic Lumbar Plexus Lumbar plexus nerve roots: 2 from 1, 2 from 2, 2 from 3: 2 nerves from 1 root: ilioinguinal (L1), iliohypogastric (L1). 2 nerves from 2 roots: genitofemoral (L1–L2), lateral cutaneous nerve of the thigh (L2–L3). 2 nerves from 3 roots: obturator (L2–L4), femoral (L2–L4). Structure of the scrotum Feature Wall

Arterial Supply Posterior scrotal branches Anterior scrotal branches Cremaster artery

Description Double layered: skin and superficial fascia (dartos): contains smooth muscle fibers—dartos muscle

Significance • Outpouching of lower anterior abdominal wall • Dartos muscle receives autonomic innervation and functions to wrinkle the skin

Origin: perineal artery

Supplies posterior aspect

Origin: external pudendal artery Origin: inferior epigastric artery

Supplies anterior aspect Supplies the superior aspect (continued)

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Structure of the scrotum (continued) Feature Nerve Supply

Description

Significance

Genital branch Origin: genitofemoral nerve of genitofemoral (L1–L2) nerve

Supplies anterolateral surface

Anterior scrotal nerves

Supplies anterior surface

Origin: ilioinguinal nerve (L1)

Posterior scrotal Origin: perineal branches of nerves pudendal nerve (S1–S4)

Supplies posterior surface

Perineal Origin: posterior femoral branches of cutaneous nerve (S2–S3) posterior femoral cutaneous

Supplies inferior surface

The testes and epididymis are presented with the reproductive organs in the pelvis and perineum chapter.

Clinical Significance Sensory Innervation of the Scrotum As the anterior aspect of the scrotum is supplied by branches of the ilioinguinal nerve and the posterior aspect by the branches of the perineal and posterior femoral cutaneous nerves, care must be taken to properly anesthetize the scrotum for surgical procedures. Structure of the spermatic cord The spermatic cord runs through the inguinal canal into the scrotum. The cord contains structures coursing between the scrotum and the abdominopelvic cavity. Structure

Description

Significance

Fascial coverings • Internal—internal • Internal spermatic— of spermatic spermatic fascia derived from transversalis cord • Middle—cremaster fascia fascia • External—external • Cremaster—derived spermatic fascia from internal oblique • External spermatic— derived from external oblique (continued)

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Structure of the spermatic cord (continued) Structure Description Components Ductus deferens Tube composed of smooth muscle Testicular artery

Arises from abdominal aorta

Artery of the ductus deferens Cremasteric artery Pampiniform plexus of veins Autonomics

Arises from inferior vesical artery Arises from inferior epigastric artery Venous plexus that drains the testes and spermatic cord Sympathetic and parasympathetic nerve network

Genital branch Origin: L1–L2; divides into of genitofemoral genital and femoral branches

Significance Conveys sperm from the epididymis to the ejaculatory duct Supplies testes and epididymis Supplies ductus deferens Supplies cremaster muscle and fascia Converges to form the testicular veins • Innervates dartos and vessels of region • Responsible for peristaltic contractions during emission Supplies cremaster muscle

Clinical Significance Temperature Regulation The cremaster muscle (skeletal muscle), found with the cremaster fascia, draws the testes toward the body in cold temperatures as part of the cremasteric reflex. The dartos muscle (smooth muscle) causes wrinkling of the scrotum to draw the testes nearer the body and reduce the surface area of the scrotum in cold temperatures.

PERITONEAL CAVITY Structure of the peritoneal cavity (Figure 2-1) The peritoneal cavity is a potential, fluid-filled space between adjacent layers of peritoneum in the abdomen. It is divided into a lesser and a greater sac that correspond to their embryologic origins as the right and left halves of the intraembryonic cavity.

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Structure of the peritoneal cavity (continued) Feature Lesser sac (omental bursa)

Superior recess of lesser sac Inferior recess of lesser sac Greater sac

Omental foramen

Paracolic gutters

Supracolic compartment

Description Bounded by: • Anterior—liver, stomach and lesser omentum • Posterior—diaphragm • Right—liver • Left—gastrosplenic and gastrorenal ligaments Limited by diaphragm and posterior leaf of coronary ligament of the liver Limited by fusion of anterior and posterior leafs of greater omentum All of the peritoneal cavity that is not the lesser sac Located posterior to the portal triad and anterior to the inferior vena cava Depressions running parallel with the ascending and descending colon along the posterior abdominal wall Formed by the mesentery of the transverse colon— the transverse mesocolon

Infracolic compartment Subphrenic spaces

Hepatorenal recess

Superior extensions of the peritoneal cavity between the diaphragm and liver Extension of peritoneal cavity inferior to the liver and anterior to the kidney and suprarenal gland

Significance • Smaller portion of the peritoneal cavity • Formed by embryologic rotation of the gut

Superior extent of the lesser sac Inferior extent of the lesser sac • Larger portion of the peritoneal cavity • Formed by embryologic rotation of the gut Connection between the lesser and greater sac • Function as channels that convey peritoneal fluid • Communication between supra- and infracolic compartments Part of the peritoneal cavity superior to the transverse mesocolon Part of the peritoneal cavity inferior to the transverse mesocolon Separated into right and left by the falciform ligament • Communicates anteriorly with the right subphrenic space • Communicates with omental bursa (lesser sac)—fluid may drain into recess from here when supine (continued)

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Feature Peritoneal Fossae Supravesical fossae Medial inguinal fossae (related to inguinal triangles) Lateral inguinal fossae

Description

Significance

Between the median and medial umbilical folds Between the medial and lateral umbilical folds

Potential site for a hernia

Lateral to the lateral umbilical folds

Deep inguinal rings found within fossae, potential site for indirect inguinal hernia

Potential site for a direct inguinal hernia

Peritoneal pouches are presented with the pelvis.

Clinical Significance Peritoneal Puncture Occasionally it is necessary to puncture the peritoneum to remove excess fluid (ascites) that accumulates during inflammation, to conduct peritoneal dialysis or administer anesthetic agents through intraperitoneal injection. Peritoneum (Figure 2-1) Structure Parietal peritoneum Visceral peritoneum Mesentery

Description Serous membrane lining the peritoneal cavity

• Double layer of peritoneum connecting intraperitoneal organs to the abdominal wall • Conveys neurovascular elements and lymphatics • Allows movement of the organ to which it is attached Peritoneal Folds Fold of parietal peritoneum Median extending from the apex of umbilical fold the bladder to the umbilicus Fold of parietal peritoneum Medial found lateral to the median umbilical umbilical fold folds (2)

Significance Lines internal surface of abdominal wall Lines external surfaces of abdominal organs • The “mesentery” refers specifically to the mesentery of the small intestine • Other mesenteries are named specifically for the organs to which they are associated (e.g., transverse mesocolon or mesoappendix) Covers the median umbilical ligament—the remnant of the urachus Covers the medial umbilical ligaments—the obliterated part of the umbilical arteries (continued)

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Peritoneum (continued) Structure Description Lateral umbilical Fold of parietal peritoneum found lateral to the medial folds (2) umbilical folds Omenta Double layer of peritoneum Greater connecting greater curvature of stomach and proximal duodenum to adjacent organs

Lesser

• Double layer of peritoneum connecting lesser curvature of the stomach and proximal duodenum to adjacent organs • Forms anterior wall of lesser sac

Associated with the Liver Falciform • Double layer of ligament peritoneum extending from umbilicus to liver on anterior abdominal wall • Continuous superiorly as left and right coronary ligament • Anterior formed by Coronary separation of leafs of ligaments falciform ligament (anterior and • Posterior is formed of posterior) peritoneal reflexion from diaphragm to liver Formed of anterior and Triangular posterior coronary ligaments ligaments (right and left) Round ligament of liver

Connective tissue cord in inferior border of falciform ligament

Significance Covers the inferior epigastric vessels

3 parts: 1. Gastrophrenic ligament—connects stomach to diaphragm 2. Gastrosplenic ligament—connects stomach to spleen 3. Gastrocolic ligament— connects stomach to transverse colon, largest part, anterior and posterior layers are fused to form a 4-layered structure 2 parts: 1. Hepatogastric ligament—connects stomach to liver 2. Hepatoduodenal ligament—connects duodenum to liver, contains portal triad: portal vein, hepatic artery and bile duct • Embryologic remnant of the ventral mesentery • Contains round ligament of the liver in its inferior, crescentic border

Bound the bare area of the liver

Formed of a peritoneal reflexion between anterior and posterior leafs of coronary ligaments Embryologic remnant of the umbilical vein

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Superior recess of omental bursa

Liver Lesser omentum Falciform ligament Subhepatic space Pancreas Stomach Duodenum Transverse mesocolon Transverse colon Inferior recess of omental bursa Mesentery of small intestine Greater omentum Jejunum Ileum Visceral peritoneum Parietal peritoneum Rectovesical pouch Urinary bladder

A Right lateral view Transverse colon

Rectum

Supracolic compartment

Transverse mesocolon Phrenicocolic ligament

Right colic flexure

Left colic flexure Tenia coli

Ascending colon

Root of mesentery of small intestine Descending colon

Right Right paracolic infracolic gutter space

Left Left infracolic paracolic space gutter

Infracolic compartment

B Anterior view

Supracolic compartment (greater sac) Omental bursa (lesser sac) Infracolic compartment (greater sac)

FIGURE 2-1. Subdivisions of peritoneal cavity. A: This median section of the abdominopelvic cavity shows the subdivisions of the peritoneal cavity. B: The supracolic and infracolic compartments of the greater sac are shown after removal of the greater omentum.The infracolic spaces and paracolic gutters determine the flow of ascitic fluid when inclined or upright. (From Moore KL, Dalley AF. Clinically Oriented Anatomy. 5th ed. Baltimore: Lippincott Williams & Wilkins; 2006:239.)

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Additional Concepts Peritoneal Relations Organs that are suspended by a mesentery are said to be intraperitoneal. Organs that lack a mesentery and are only partially covered with peritoneum are said to be extraperitoneal (retroperitoneal or subperitoneal provides more indication of their location). Median Umbilical Ligament The median umbilical ligament is formed by the urachus, the obliterated portion of the allantois, connecting the apex of the bladder with the umbilicus. Medial Umbilical Ligaments The medial umbilical ligaments are formed by the obliterated portions of the umbilical arteries distal to the superior vesical arteries.

Clinical Significance Herniae A direct inguinal hernia (acquired) exits the abdomen via the medial inguinal fossa or inguinal triangle, which is bounded medially by the semilunar line (lateral border of rectus abdominis), laterally by the lateral umbilical folds and inferiorly by the inguinal ligament. An indirect inguinal hernia (congenital) exits the abdomen via the deep inguinal ring and passes through the inguinal canal into the scrotum. Adhesions Adhesions may develop in the peritoneal cavity as a result of inflammation of the peritoneum (peritonitis) or previous surgery, which may need to be removed if they compromise the function of the viscera. Mnemonic Structures forming folds: IOU: From lateral to medial: lateral umbilical ligament: Inferior epigastric vessels medial umbilical ligament: Obliterated umbilical artery median umbilical ligament: Urachus

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ESOPHAGUS Structure of the esophagus The esophagus is a muscular tube extending from the cricoid cartilage to the gastroesophageal junction; it enters the abdomen through the esophageal hiatus of the diaphragm. The nature of the musculature of the esophagus changes throughout its course: ■ ■ ■

upper third—skeletal muscle middle third—mixture of smooth and skeletal muscle lower third—smooth muscle

Feature Sphincters

Description 2 sphincters: 1. Upper esophageal sphincter—skeletal muscle 2. Lower esophageal sphincter—smooth muscle and skeletal muscle of diaphragm

Innervation

• Skeletal muscle part— recurrent branches of the vagus nerve • Smooth muscle part— esophageal plexus

Arterial supply

Inferior thyroid, esophageal, bronchial, left gastric and left inferior phrenic arteries Esophageal veins empty into the inferior thyroid, azygos, hemiazygos and gastric veins

Venous drainage

Significance • Upper sphincter composed mainly of cricopharyngeus • Lower sphincter— smooth muscle and muscular diaphragmatic esophageal hiatus prevent gastroesophageal reflux Esophageal plexus— parasympathetic fibers from the vagus nerves and sympathetic fibers from sympathetic chain and greater splanchnic nerve Arterial supply is generally via whatever arteries lie near this long longitudinally oriented structure Important contributor to the portal-caval anastomosis

Clinical Significance Esophageal Varices Esophageal varices are dilated esophageal veins that may rupture in cases of portal hypertension. Pyrosis Pyrosis (heartburn) is usually the result of regurgitation of stomach contents into the lower esophagus.

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STOMACH Structure of the stomach (Figure 2-3) The stomach is the muscular organ of digestion; it produces chyme through enzymatic digestion. Feature Parts Cardia

Description

Significance

Part surrounding cardial orifice

Fundus

Part superior to cardial orifice Part between fundus and pyloric antrum • Distal-most part of the stomach • Possesses smooth muscle sphincter— pyloric sphincter, which guards the pyloric orifice that opens into the duodenum • Funnel-shaped • Divided into the pyloric antrum (wide) and pyloric canal (narrow)

Cardial orifice—funnelshaped opening of stomach that receives the esophagus Typically dilated and gasfilled Major part of the stomach Pyloric sphincter controls release of gastric contents into the duodenum and prevents reflux from duodenum into stomach

Body Pylorus

Curvatures Greater Lesser

Interior Rugae (gastric folds)

Directed inferior and to the left Directed superior and to the right

Longer, convex curvature

Longitudinal folds of gastric mucosa

Function to increase surface area and allow for distension

• Shorter, concave curvature • Bears the angular incisure—outer representation of the junction of the body and pyloric part

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Clinical Significance Pylorospasm Pylorospasm is the failure of the pyloric sphincter to relax, which prevents food from passing from the stomach to the duodenum, often occurs in infants and may result in vomiting.

Vessels of the stomach (Figure 2-4) Artery Celiac trunk

Origin Abdominal aorta

Splenic

Celiac trunk

Hepatic

Gastroduodenal

Hepatic

Right gastric Left gastric Right gastro-omental

Celiac trunk Gastroduodenal

Left gastro-omental Short gastric Vein Left gastric Right gastric Left gastro-omental Right gastro-omental Short

Splenic

Description • Supplies embryologic foregut • Gives rise to: splenic, hepatic and left gastric arteries • Supplies the spleen • Gives rise to left gastroomental and short gastric arteries to the stomach • Supplies the liver • Gives rise to gastroduodenal and right gastric arteries to the stomach • Supplies the stomach, duodenum and liver • Gives rise to right gastroomental to the stomach Supplies lesser curvature of the stomach Supplies greater curvature of the stomach Supply body of stomach

Termination Portal

Description

Splenic Superior mesenteric Splenic

Drain greater curvature of stomach

Drain lesser curvature of stomach

Drain body of stomach

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Nerves of the stomach Nerve Parasympathetic

Sympathetic

Visceral afferent

Origin Vagus nerves

Structures Innervated Anterior and posterior vagal trunks enter abdomen through the esophageal hiatus Presynaptics originate • Presynaptic sympathetics from the intermedioare conveyed to the celiac lateral cell column of the plexus/ganglia spinal cord and travel • Postsynaptic fibers travel in the sympathetic on branches of the celiac trunks and splanchnic trunk to the stomach nerves to reach • Reduces motility, activates abdominal plexuses sphincters, vasoconstricts and decreases glandular activity Cell bodies located in Stomach sensitive to spinal ganglia stretching and distension

SMALL INTESTINE Structure of the small intestine (Figures 2-3 and 2-5) The small intestine extends from the pylorus to the cecum. It is the primary site of digestion and absorption in the body. The small intestine is divided into three parts: 1. duodenum 2. jejunum 3. ileum Structure Duodenum

Description • 1st part of small intestine • Divided into 4 parts: 1. Superior 2. Descending 3. Horizontal 4. Ascending • Superior part is intraperitoneal, the remaining parts are retroperitoneal

Significance • Descending part receives the bile and main pancreatic ducts via hepatopancreatic ampulla • Ascending part continuous with jejunum at duodenojejunal junction • 1st part referred to as duodenal cap/bulb (continued)

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Structure of the small intestine (continued) Structure Duodenojejunal junction

Description Junction of duodenum and jejunum, evidenced by the duodenojejunal flexure

Jejunum

• 2nd part of the small intestine • Intraperitoneal, connected to the posterior abdominal wall by the mesentery • 3rd part of the small intestine • Intraperitoneal, connected to the posterior abdominal wall by the mesentery Junction of the ileum and the cecum

Ileum

Ileocecal junction

Significance The sharp angle of the duodenojejunal flexure is supported by the suspensory muscle of the duodenum (ligament of Treitz)—a slip of fibromuscular tissue that supports the flexure Constitutes ⬃2/5 of the small intestine distal to the duodenum

Constitutes the distal part of the small intestine, extending from the jejunum to the ileocecal junction Invagination of the ileum into the cecum forms folds superior and inferior to the ileal orifice, forming the ileocecal valve

Additional Concept Distinguishing Characteristics between the Jejunum and Ileum The jejunum has greater vascularity, longer vasa recta, fewer and larger arterial arcades, less fat in the mesentery, more prominent plicae circulares, and fewer lymphatic elements than the ileum. Vessels of the small intestine (Figure 2-3) The celiac trunk and gastroduodenal arteries are presented with the vessels of the stomach. Artery Superior pancreaticoduodenal

Origin Gastroduodenal

Description Supplies proximal part of duodenum (continued)

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Vessels of the small intestine (continued) Artery Superior mesenteric

Origin Abdominal aorta

Inferior pancreaticoduodenal Arterial arcades

Superior mesenteric

Description • Supplies alimentary canal to left colic flexure • Supplies embryologic midgut Supplies distal part of duodenum Gives rise to vasa recta that supply the jejunum and ileum

Additional Concept Venous Drainage Venous drainage parallels arterial supply and terminates in the portal vein. Embryologic Arterial Supply The descending part of the duodenum marks the transition between the embryologic foregut and midgut, the location is marked by anastomosis of branches of the celiac trunk (artery of the foregut) with branches of the superior mesenteric artery (artery of the midgut). Nerves of the small intestine Nerve Origin Parasympathetic Vagal—primarily the posterior vagal trunk

Sympathetic

Presynaptics originate from the intermediolateral cell column of the spinal cord and travel in the sympathetic trunks and splanchnic nerves to reach abdominal plexuses

Structures Innervated • Presynaptic parasympathetic fibers synapse in the myenteric and submucosal plexuses in the wall of the small intestine • Increases motility and glandular secretion and inhibits sphincters • Presynaptic sympathetics are conveyed to the celiac and superior mesenteric plexuses/ganglia • Postsynaptic fibers travel on branches of the superior mesenteric artery to the small intestine • Reduces motility, activates sphincters, vasoconstricts and decreases glandular activity (continued)

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Nerves of the small intestine (continued) Nerve Origin Visceral afferent Cell bodies located in spinal ganglia

Structures Innervated Small intestine sensitive to stretching, distension, and pain

LARGE INTESTINE Structure of the large intestine (Figure 2-2) The large intestine extends from the ileocecal junction to the anus. It is divided into four parts: 1. cecum 2. colon 3. rectum 4. anal canal The large intestine is the part of the digestive tract distal to the small intestine; it is primarily responsible for water and electrolyte resorption. Structure Parts Cecum

Appendix

Colon

Description

Significance

• 1st part of large intestine • Continuous with ascending colon • Ileum joins it at ileocecal junction • Diverticulum extending from cecum • Possesses a mesentery— mesoappendix • 2nd part of large intestine • Divided into 4 parts: 1. Ascending colon extends from cecum to right colic flexure 2. Transverse colon extends from right colic flexure to left colic flexure 3.Descending colon extends from left colic flexure to sigmoid colon 4. Sigmoid colon follows an S-shaped course to the rectum

Mostly covered by visceral peritoneum, although has no mesentery

Variable location, but usually is posterior to the cecum

• The ascending and descending colon are retroperitoneal, although they are only loosely fixed to the posterior abdominal wall by a loose connective tissue fascia—fusion fascia and, therefore, easily mobilized during surgery • On the lateral aspects, are the paracolic gutters • The transverse and sigmoid colon each have mesenteries— the transverse and sigmoid mesocolons (continued)

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Structure of the large intestine (continued) Structure

Description

Rectum

• 3rd part of large intestine • Dilated terminal portion— • Extends from the sigmoid the ampulla, retains feces colon at S3 to the anal until defecation canal • The proximal third of the • Possesses 3 lateral flexures rectum is covered by that correspond to 3 transperitoneum on the anterior verse rectal folds, which and lateral aspect, the correspond to thickenings middle third only has of the muscular wall peritoneum on the anterior surface, whereas the inferior 3rd is subperitoneal

Significance

Anal canal

• 4th part of large intestine • The anorectal flexure is • Begins at the anorectal the primary structure that flexure at the level of the maintains fecal continence, pelvic diaphragm and it is a sharp bend maintained extends to the anus by tonic contraction of • Internally possesses anal puborectalis; its relaxation columns—longitudinal is necessary if defecation ridges joined at their base is to occur by anal valves, anal glands • Feces compressing the open into the anal sinuses anal sinuses causes (recesses formed by anal exudation of mucus that valves) lubricates the anal canal

Features Teniae coli

3 longitudinally oriented bands of smooth muscle of the large intestine

The longitudinal layer of smooth muscle surrounding the digestive tract is reduced to 3 bands over the large intestine

Haustra

Sacculations of the large intestine

Slow the passage of feces through the large intestine

Omental appendices

Small, fatty projections hanging from the wall of the large intestine

Allow for reduced friction with nearby structures during movement of the large intestine as feces passes through

Additional Concept Differences between the Small and Large Intestine The large intestine has a larger diameter than the small intestine and possesses teniae coli, haustra and omental appendices, all of which are unique to the large intestine.

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Sigmoid colon Rectum

Ampulla of rectum

FIGURE 2-2. Anteroposterior barium radiograph showing parts of the large intestine; note the haustra and flexures of the colon. (From Dudek RW, Louis TM. High-Yield Gross Anatomy. 3rd ed. Baltimore: Lippincott Williams & Wilkins; 2008:138.)

Clinical Significance McBurney’s Point Usual location of proximal (open end) of the appendix, located one third of the way along an oblique line connecting the anterior superior iliac spine to the umbilicus. Sphincters of Anal Canal The anal canal is surrounded by two sphincters, both of which are involved in the maintenance of fecal continence, the internal (involuntary) and external (voluntary, divided into deep, superficial, and subcutaneous parts) anal sphincters. Pectinate Line The inferior border of the anal valves forms the pectinate line. Above the pectinate line, the anal canal is derived from the embryologic hindgut (visceral—autonomic innervation, inferior mesenteric arterial supply, venous drainage to portal system, and lymphatics to internal iliac nodes), below the line it is derived from the proctodeum (somatic—somatic

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innervation, internal iliac arterial supply, venous drainage to caval system, and lymphatics to inguinal nodes). Teniae Coli Proximally, the teniae coli converge at the base of the appendix and thereby aid in location of the appendix during surgery. Vessels of the large intestine Artery

Origin

Description

Superior mesenteric

Abdominal aorta

• Supplies alimentary canal to left colic flexure • Supplies embryologic midgut

Ileocolic

Superior mesenteric

• Supplies cecum • Gives rise to appendicular artery

Appendicular

Ileocolic

Supplies appendix

Right colic

Superior mesenteric

Supplies ascending colon

Middle colic

Supplies transverse colon

Inferior mesenteric Abdominal aorta

• Supplies alimentary canal to the anal canal • Supplies embryologic hindgut

Left colic

Supplies descending colon

Sigmoid

Inferior mesenteric

Supplies sigmoid colon

Marginal

Ileocolic, right Anastomotic loop forming collateral colic, middle circulation along the large intestine colic, left colic, and sigmoids

Superior rectal

Inferior mesenteric

Middle rectal

Inferior vesical Mid and inferior aspect of rectum (male) or uterine (female)

Inferior rectal

Internal pudendal

Superior aspect of rectum

Anal canal

Additional Concept Venous Drainage Venous drainage parallels arterial supply and terminates in the portal vein until the level of the junction of the superior and middle aspects of the rectum; inferior to this point, venous drainage is to the caval system.

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Nerves of the large intestine Nerve Origin Structures Innervated Large Intestine Proximal to Pectinate Line of Anal Canal Parasympathetic • Vagal—to the • Presynaptic parasympathetic fibers mid-transverse synapse in the in the wall of the colon large intestine • S2–S4 via • Increases motility and glandular pelvic splanch- secretion and inhibits sphincters nic nerves Sympathetic Presynaptics • Postsynaptic fibers travel on originate from branches of superior and inferior the intermediola- mesenteric arteries to the large teral cell column intestine of the spinal cord • Reduces motility, activates sphincters, and travel in the vasoconstricts and decreases sympathetic glandular activity trunks and splanchnic nerves to reach abdominal plexuses Visceral afferent Cell bodies • Large intestine sensitive to pain, located in spinal stretching and distension ganglia • Afferents involved in reflexes travel with the vagus nerve Large Intestine Distal to Pectinate Line of Anal Canal Inferior rectal Pudendal • Somatic innervation • Anal canal inferior to pectinate line

Structure of the liver (Figures 2-3 and 2-5) The liver is the largest internal organ and the largest gland in the body. It is surrounded by a connective tissue capsule—Glisson’s capsule. The liver is divided into anatomic lobes: ■ ■ ■ ■

right left caudate quadrate

Functional units of the liver are called hepatic lobules— plates of hepatocytes surrounded by sinusoids, which are organized around portal triads. The liver receives all substances absorbed by the digestive tract (except lipids), stores glycogen, and secretes bile.

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Structure of the liver (continued) Structure Description Anatomic Lobes Right Located to the right of the right sagittal fissure Left Caudate

Quadrate

Features Porta hepatis

Bare area

Left sagittal fissure

Right sagittal fissure

Right and left hepatic ducts

Significance Demarcated by the left and right sagittal fissures and the porta hepatis

Located to the left of the left sagittal fissure Between the left and right sagittal fissures, posterior to the porta hepatis Between the left and right sagittal fissures, anterior to the porta hepatis Fissure on inferior aspect of • Structures passing through liver where structures enter the porta hepatis include: and leave that are enclosed 1. Common bile duct in the hepatoduodenal 2. Portal vein ligament 3. Hepatic artery 4. Lymphatics • The first 3 structures compose the portal triad • Area on posterior aspect Provides potential route of of liver that lacks infection between the peritoneum abdominal and thoracic • Bounded by the coronary cavities ligaments • Fissure on inferior aspect Contains: of liver • Ligamentum venosum— • Separates the left lobe remnant of ductus from the quadrate and venosus, an embryologic caudate lobes shunt for blood • Round ligament—remnant of umbilical vein • Fissure on inferior aspect Contains: of liver • Inferior vena cava in • Separates quadrate and the groove for the caudate lobes from right inferior vena cava lobe of liver • Gall bladder in the fossa of the gall bladder Drain bile from the right and • Right and left bile ducts join left lobes inferior to the liver to form the common hepatic duct • Release of bile into the hepatopancreatic ampulla is controlled by the sphincter of the bile duct

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Falciform ligament Round ligament Right branches of hepatic duct, hepatic artery, and portal vein

Left branches of common hepatic duct, portal vein, and hepatic artery Common hepatic artery Stomach

Gallbladder

Spleen

Cystic artery

Splenic artery Splenic Inferior vein mesenteric vein Superior mesenteric artery Superior mesenteric vein

Portal vein Pylorus Duodenum Head of pancreas

FIGURE 2-3. Liver. Anterior view. (Asset provided by Anatomical Chart Company.)

The remainder of the biliary tree is presented with the gall bladder and pancreas.

Additional Concept Functional Divisions of the Liver The liver can also be divided functionally into right and left functional lobes, based on the branching pattern of the right and left hepatic arteries.

Clinical Significance Cirrhosis Cirrhosis of the liver is characterized by the replacement of healthy liver cells with fat and fibrous tissue; it is most commonly seen in alcoholics and is a common cause of portal hypertension.

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LIVER Vessels of the liver (Figures 2-3 and 2-4) Artery Celiac trunk

Origin Abdominal aorta

Hepatic

Celiac trunk

Right and left hepatic Vein Right, middle and left hepatic

Hepatic

Portal

Termination Inferior vena cava Sinusoids of liver

Description • Gives rise to splenic, hepatic, and left gastric arteries • Supplies embryologic foregut • Supplies the liver • Gives rise to right and left hepatic arteries Supply right and left lobes of liver Description • Drain into inferior vena cava immediately inferior to the diaphragm • Help to hold liver in place • Formed by the junction of the splenic and superior mesenteric veins, which typically receive the inferior mesenteric vein • Conveys all venous blood and absorbed nutrients from the digestive tract from the inferior aspect of the esophagus to the anal canal

Clinical Significance Portal Hypertension Portal hypertension is indicated by a rise in pressure in the portal vein and is often caused by cirrhosis, characterized by scarring and fibrosis of the liver. This causes blood to flow into the systemic (caval) system at sites of portal-systemic anastomosis, producing varicose veins. Nerves of the liver Nerve Origin Parasympathetic Vagus nerves

Sympathetic

Presynaptics originate in the intermediolateral cell column of the spinal cord and travel in the sympathetic trunks and splanchnic nerves to reach abdominal plexuses

Structures Innervated Anterior and posterior vagal trunks enter abdomen through the esophageal hiatus • Presynaptic sympathetics are conveyed to the celiac and hepatic plexus • Postsynaptic fibers travel on branches of the hepatic artery to the liver

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Right inferior phrenic artery Splenic artery Superior mesenteric artery (to midgut)

Aorta Esophagus Left inferior phrenic artery Celiac trunk (artery; to foregut) Left gastric artery Spleen Posterior gastric artery

Duodenum

Stomach

Small intestine

Inferior mesenteric artery (to hindgut) Descending colon

Ascending colon

A Anterior view

Right lobe of liver Cystic vein Gallbladder Portal vein Right gastric vein Pancreaticoduodenal veins Duodenum Middle colic vein

Right colic vein Ileocolic vein Appendicular vein B Anterior view

To azygos venous system Esophageal branch Cardial notch Left gastric vein Short gastric vein Spleen Splenic vein Left and right gastro-omental veins Pancreas Inferior mesenteric vein Superior mesenteric vein Left colic veins Jejunal and ileal veins Sigmoid veins Superior rectal veins

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GALL BLADDER Structure of the gall bladder (Figures 2-3 and 2-5) The gall bladder is a pear-shaped organ located in the anterior aspect of the right sagittal fissure of the liver in the gall bladder fossa. It stores and concentrates bile. Structure Fundus

Body Neck

Description Significance Expanded anterior-most end Located near the 9th costal cartilage in the midclavicular line Located between the fundus In contact with inferior and neck surface of liver Narrow posterior-most part; Makes S-shaped bend to directed toward porta hepatis join cystic duct

Additional Concept Extrahepatic Duct System The cystic duct of the gall bladder joins the common hepatic duct—formed by the junction of the right and left hepatic ducts—to form the common bile duct. The cystic duct drains bile from the gall bladder and the mucosa of the cystic duct is folded in a spiral fashion to form the spiral valve, which functions to keep the duct open. The hepatic ducts function to drain bile from the liver. The common bile duct ends at the hepatopancreatic ampulla, where it joins the main pancreatic duct; release of contents into the duodenum is controlled by the sphincter of the hepatopancreatic ampulla—sympathetic innervation causes the sphincter to contract. The remainder of the biliary tree is presented with the liver and pancreas.

FIGURE 2-4. Arterial supply and venous drainage of GI tract. A: The arterial supple is demonstrated. B: The venous drainage is shown. The portal vein drains poorly oxygenated, nutrient-rich blood from the gastrointestinal tract, spleen, pancreas, and gallbladder to the liver. The black arrow indicates the communication of the esophageal vein with the azygos (systemic) venous system. (From Moore KL, Dalley AF. Clinically Oriented Anatomy. 5th ed. Baltimore: Lippincott Williams & Wilkins; 2006:245.)

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Right hepatic duct

Left hepatic duct

Common hepatic duct

Gallbladder

Cystic duct

Common bile duct

Duodenum

FIGURE 2-5. Endoscopic retrograde cholangiograph shows the normal gallbladder and biliary tree. Note that the cystic duct normally lies on the right side of the common hepatic duct and joins it superior to the duodenal cap. (From Dudek RW, Louis TM. HighYield Gross Anatomy. 3rd ed. Baltimore: Lippincott Williams & Wilkins; 2008:125.)

Clinical Significance Gall Stones Concretions (gall stones) from the gall bladder may lodge in the hepatopancreatic ampulla, causing bile to backup into the pancreas, leading to pancreatitis, jaundice, and pain. The gall bladder is often removed via laparoscopic cholecystectomy.

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Vessels of the gall bladder (Figures 2-3 and 2-4) Artery

Origin

Description

Celiac trunk

Abdominal aorta

Gives rise to splenic, hepatic, and left gastric arteries; supplies embryologic foregut

Hepatic

Celiac trunk

Gives rise to right and left hepatic arteries

Right and left hepatic arteries

Hepatic

Gives rise to cystic

Cystic

Right hepatic

Supplies gall bladder and cystic duct

Additional Concept Venous Drainage Venous drainage from the biliary tree and neck of the gall bladder is via the cystic veins—they either drain directly into the liver or into the portal vein. Venous drainage from the remainder of the gall bladder is directly into the liver. Nerves of the gall bladder Nerve

Origin

Structures Innervated

Parasympathetic

Vagal

Presynaptic parasympathetic fibers synapse on nerve cell bodies in the wall of the gall bladder

Sympathetic

Presynaptics Postsynaptic fibers travel on branches originate in the of arteries to reach the gall bladder intermediolateral cell column of the spinal cord and travel in the sympathetic trunks and splanchnic nerves to reach abdominal plexuses

Visceral afferent

Cell bodies Gall bladder sensitive to pain located in spinal • Somatic afferent innervation, ganglia primarily mediating pain • Conveyed to cervical spinal cord

Right phrenic

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PANCREAS Structure of the pancreas (Figures 2-3 and 2-5) The pancreas is an elongated, lobulated, retroperitoneal organ found along the posterior abdominal wall. It has both an exocrine and endocrine function: ■ ■

exocrine—produces pancreatic digestive enzymes endocrine—produces glucagon and insulin

Structure Parts Head

Description

Significance

Expanded part

Uncinate process

Hook-shaped projection from head

Neck

Short part between head and body

Body

Part between neck and tail

Tail

• Mobile • Located in splenorenal ligament

Lies in concavity of the C-shaped duodenum • Posterior relations: inferior vena cava, right renal vessels and left renal vein • Anterior relations: superior mesenteric artery Overlies junction of superior mesenteric and splenic veins to form the portal vein Lies to the left of the superior mesenteric vessels Related to hilum of spleen and left colic flexure

Features Main pancreatic • Begins at tail and extends • Merges with bile duct in duct to head head of pancreas to form • Conveys pancreatic hepatopancreatic enzymes ampulla, which opens into • Release of pancreatic descending part of enzymes regulated by duodenum at the major smooth muscle sphincter— duodenal papilla sphincter of pancreatic • Release of contents into duct the duodenum is controlled by a smooth muscle sphincter—hepatopancreatic sphincter (sphincter of Oddi) that surrounds the ampulla Accessory • Drains uncinate process Empties into descending part pancreatic duct and part of head of of duodenum at minor pancreas duodenal papilla • Conveys pancreatic enzymes

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The remainder of the biliary tree is presented with the gall bladder and liver.

Clinical Significance Pancreatic Cancer Pancreatic cancer results in a low survival rate as a result of difficulty to identify and treat because of its location and easy route of metastasis to the liver. Vessels of the pancreas (Figures 2-3 and 2-4) Artery Celiac trunk

Origin Abdominal aorta

Splenic

Celiac trunk

Dorsal pancreatic Great pancreatic Caudal pancreatic Hepatic Gastroduodenal

Splenic

Celiac Hepatic

Anterior and posterior superior pancreaticoduodenals Superior mesenteric

Abdominal aorta

Anterior and posterior inferior pancreaticoduodenals

Description • Gives rise to splenic, hepatic, and left gastric arteries • Supplies embryologic foregut Gives rise to dorsal, caudal, and great pancreatic arteries Supplies body and tail

Gives rise to gastroduodenal Gives rise to anterior and posterior superior pancreaticoduodenals Gastroduodenal Supply head and neck

Superior mesenteric

• Gives rise to anterior and posterior inferior pancreaticoduodenals • Supplies alimentary canal to left colic flexure • Supplies embryologic midgut Supply head and neck

Additional Concept Venous Drainage Venous drainage is via the splenic and superior mesenteric veins, which join to form the portal vein.

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Nerves of the pancreas Nerve Parasympathetic

Sympathetic

Origin Vagus nerves

Structures Innervated • Anterior and posterior vagal trunks enter abdomen through the esophageal hiatus • Secretomotor, although most pancreatic secretion is controlled hormonally Presynaptics • Presynaptic sympathetics are originate from conveyed to the celiac and superior the intermediomesenteric plexuses lateral cell • Postsynaptic fibers travel on branches column of the of celiac and superior mesenteric spinal cord and arteries to pancreas travel in the sym- • Most pancreatic secretion is pathetic trunks controlled hormonally splanchnic nerves to reach abdominal plexuses

SPLEEN Structure of the spleen (Figure 2-3) The spleen is a lymphatic organ located in the upper left quadrant of the abdomen. It functions to remove old or abnormal red blood cells, stores platelets, and produces antibodies. Structure Hilum

Gastrosplenic ligament Splenorenal ligament

Description Medially directed concavity

Significance • Site of entry and exit to and from the spleen • Tail of the pancreas contacts spleen here Connects hilum of spleen to • Part of greater omentum greater curvature of stomach • Contains short gastric and left gastroepiploic vessels Connects hilum of spleen • Double layer of peritoneum to left kidney • Contains splenic vessels

Clinical Significance Splenomegaly The spleen may enlarge (splenomegaly) from a variety of reasons or may be damaged by broken ribs, causing profuse bleeding.

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Vessels of the spleen (Figures 2-3 and 2-4) Artery Celiac trunk

Origin Abdominal aorta

Splenic

Celiac trunk

Description • Gives rise to splenic, hepatic, and left gastric arteries • Supplies embryologic foregut • Easily identified by tortuous course • Travels in splenorenal ligament • Supplies spleen via 5 terminal branches

Additional Concept Venous Drainage Venous drainage is via the splenic vein, which joins the superior mesenteric vein to form the portal vein. Nerves of the spleen Nerve Parasympathetic

Sympathetic

Origin Vagus nerves

Structures Innervated Anterior and posterior vagal trunks enter abdomen through the esophageal hiatus Presynaptics • Presynaptic sympathetics are originate from conveyed to the celiac plexus/ganglia the intermedio- • Postsynaptic fibers travel on branches lateral cell of the splenic artery to the spleen column of the spinal cord and travel in the sympathetic trunks and splanchnic nerves to reach abdominal plexuses

KIDNEYS Structure of the kidneys (Figures 2-6 and 2-7) The kidneys and ureters are retroperitoneal organs located along the posterior abdominal wall. The kidneys function to remove excess water, salts, and wastes from the blood. The ureters convey urine from the kidney to the urinary bladder.

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Structure of the kidneys (continued) Structure Parts Renal capsule

Renal cortex

Renal medulla Renal hilum Renal pyramid

Renal papilla Renal sinus

Minor calyces Major calyces

Renal pelvis

Features Perirenal fat

Renal fascia

Pararenal fat

70

Description

Significance

Thin connective tissue capsule that surrounds kidney • Between renal capsule and renal medulla • Extends into renal medulla as renal columns Between renal cortex and renal hilum Concave medial-margin of kidney • 5–10; conical-shaped • Base adjacent to cortex, apex forms renal papilla

• Outer surface of kidney • Surrounded by perirenal fat Consists of cortical labyrinth and cortical rays

Contains renal pyramids and renal columns Bounds renal sinus • Compose major part of medulla • Renal columns intervene between adjacent pyramids Open into minor calyces

• 5–10 • Tip of renal pyramid Area bounded by renal hilum • Space in concave medialmargin of kidney • Contains renal vein, renal artery, and renal pelvis from anterior to posterior Located in renal sinus; Several minor calyces convey urine merge to form major calyces • Formed by merging of several minor calyces • Several major calyces merge to form renal pelvis • Located in renal sinus Narrows to form ureter— • Proximal expanded end of • Retroperitoneal ureter • Conveys urine from kidney • Formed by merging of to urinary bladder major calyces Layer of protective fat surrounding kidney and suprarenal glands Membranous layer between peri- and pararenal fat

Fat external to renal fascia

Continuous with fat in renal sinus • Surrounds kidney, suprarenal gland, and perirenal fat • Continuous with fascia on inferior aspect of diaphragm Thick, protective layer of fat

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Renal lobe Renal column

Renal papilla

Minor calyx Renal capsule

Major calyx Renal pelvis

Hilum Renal pyramids Ureter

Cortex

Medulla

FIGURE 2-6. Longitudinal section of the kidney, near the hilum. (From Stedman’s Medical Dictionary. 27th ed. Baltimore: Lippincott Williams & Wilkins; 2000.)

Renal pyramids

Major calyx Renal pelvis

Ureter

Minor calyx

Left kidney

FIGURE 2-7. Intravenous urogram showing left kidney and proximal ureter; note the calyces and renal pelvis. (From Dudek RW, Louis TM. High-Yield Gross Anatomy. 3rd ed. Baltimore: Lippincott Williams & Wilkins; 2008:164.)

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Clinical Significance Constrictions of the Ureters Ureters are constricted at three places: (1) at the junction with the renal pelvis; (2) where they cross the pelvic brim; and (3) as they pass through the wall of the urinary bladder. Kidney Transplantation Kidney transplantation is a well-established procedure to replace failing kidneys. The transplanted kidney is placed in the iliac fossa (of the pelvis) for support. Kidney Stones Kidney stones (renal calculi) are concretions that form in the kidneys and may lodge in the calices, ureters, or urinary bladder. Kidney stones may block urine passage and cause pain referred to nearby regions. Vessels of the kidneys and ureters Artery

Origin

Description

Right and left renal Abdominal aorta

• Gives rise to 4–5 segmental arteries • Supply superior aspect of ureter

Segmental (4–5)

Supply segments of the kidney

Renal arteries

Right and left Abdominal gonadal (testicular aorta or ovarian)

Supply middle aspects of ureter

Abdominal aorta

Supply inferior aspects of ureter

Vein

Continuous with thoracic aorta Termination

Description

Renal

Inferior vena cava

Drain kidneys and ureters

Gonadal

• Right gonadal Drain ureters terminates in inferior vena cava • Left gonadal terminates in left renal vein

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Nerves of the kidneys and ureters Nerve

Origin

Structures Innervated

Sympathetic

Presynaptics originate intermediolateral cell column of the spinal cord travel in sympathetic trunks and splanchnic nerves to reach abdominal plexuses

• Presynaptic sympathetics are conveyed to the renal, abdominal aortic and superior hypogastric plexuses/ganglia • Postsynaptic fibers travel on arterial branches to kidney and ureter; regulate blood pressure by effecting renin release

Visceral afferent

Cell bodies located in spinal ganglia

Mediate pain sensation

Additional Concept Parasympathetic Innervation Parasympathetic innervation of the kidneys is negligible. Autonomic innervation of the ureters is modulatory, but not necessary to maintain the peristaltic contractions that convey urine to the bladder.

SUPRARENAL GLANDS Structure of the suprarenal glands The suprarenal glands are positioned between the kidneys and crura of the diaphragm. The right gland is pyramidalshaped, whereas the left is crescent-shaped. They are surrounded by perirenal fat and renal fascia and separated from the kidney connective tissue. The suprarenal glands function to secrete hormones and norepinephrine and epinephrine. Structure

Description

Significance

Cortex

Outer part

Secretes corticosteroids and androgens

Medulla

Inner part

• Secretes norepinephrine and epinephrine • Composed of modified postsynaptic sympathetic neurons

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Vessels of the suprarenal glands (Figure 2-4) Artery Inferior phrenic

Origin Abdominal aorta Superior suprarenal Inferior phrenic Middle suprarenal Abdominal aorta Renal Inferior suprarenal Renal Vein Termination Right suprarenal Inferior vena cava Left suprarenal Left renal

Description Gives rise to superior suprarenal Part of rich blood supply to gland Gives rise to inferior suprarenal Part of rich blood supply to gland Description Drain gland

Nerves of the suprarenal glands Nerve Sympathetic

Origin Presynaptics originate from the intermediolateral cell column of the spinal cord and travel in the sympathetic trunks and splanchnic nerves to reach abdominal plexuses

Structures innervated Presynaptic sympathetics are conveyed to the suprarenal glands by traveling on arterial branches, where they synapse on cells of the medulla

ABDOMINAL LYMPHATICS Abdominal lymphatics Structure Description Drainage Abdominal wall Superficial lymphatic vessels • Superior to umbilicus— accompany subcutaneous drain to axillary nodes veins • Inferior to umbilicus— drain to superficial inguinal nodes Esophagus Into left gastric lymph Left gastric nodes drain into nodes celiac nodes Stomach Vessels accompany arteries Lymph is collected in gastric along curvatures of stomach and gastro-omental nodes, which drain into pancreaticosplenic, pyloric, and pancreaticoduodenal lymph nodes, all of which eventually drain to the celiac nodes (continued)

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Abdominal lymphatics (continued) Structure Small intestine

Large intestine

Spleen

Description Drainage • Duodenum: vessels • Duodenum: anterior vessels accompany arteries drain into pancreaticoduo• Jejunum and ileum: denal nodes, which drain drainage begins as specialinto pyloric nodes; posterior ized vessels—lacteals in vessels drain into superior the intestinal villi mesenteric nodes, all of which eventually drain into celiac nodes • Jejunum and ileum: lacteals form vessels that drain into juxta-intestinal nodes to mesenteric nodes to superior central nodes, all of which eventually drain into superior mesenteric lymph nodes that drain to the ileocolic nodes • Cecum and appendix: • Cecum and appendix: nodes vessels to the nodes in the in the mesoappendix and mesoappendix and ileocolic ileocolic nodes drain to the lymph nodes superior mesenteric nodes • Ascending, descending, • Ascending, descending, and sigmoid colon: vessels and sigmoid colon: epiploic to epicolic and paracolic and paracolic nodes drain nodes to ileocolic and right colic • Transverse colon: vessels nodes, which drain to to middle colic nodes superior mesenteric lymph • Rectum: superior half: nodes drain to pararectal nodes; • Transverse colon: middle inferior half: drain to colic nodes drain to supersacral nodes ior mesenteric nodes • Anal canal: superior to • Rectum: pararectal nodes pectinate line: drain to drain to inferior mesenteric internal iliac nodes; nodes, sacral nodes follow inferior to pectinate line: middle rectal vessels to drain to superficial inguinal internal iliac nodes nodes • Anal canal: internal iliac nodes drain to the common iliac and eventually the lumbar lymph nodes; superficial inguinal nodes drain to the deep inguinal lymph nodes Vessels follow arteries from Vessels lead to the hilum pancreaticosplenic nodes, which lead to superior mesenteric lymph nodes (continued)

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Abdominal lymphatics (continued) Structure Pancreas

Suprarenal glands Kidney and ureter

Gall bladder Liver

Description Vessels follow arteries

Drainage Vessels lead to pancreaticosplenic nodes and pyloric nodes, which lead to the superior mesenteric lymph nodes Drain to lumbar lymph nodes

Kidney and superior aspect of ureter: vessels follow arteries

• Kidney and superior aspect of ureter: drain to the lumbar nodes • Mid-ureter: drain to common iliac nodes • Inferior ureter lymph is conveyed to iliac lymph nodes Lymphatics are first conveyed Lymph from hepatic nodes is to the hepatic nodes conveyed to celiac nodes Efferent lymphatics drain to • Produces ⬃50% of the the hepatic nodes (deep lymph conveyed by the lymphatics), to phrenic nodes thoracic duct (superficial lymphatics) or • Most lymph from the liver posterior mediastinal nodes is conveyed to the cisterna chyli—the dilated beginning of the thoracic duct

Additional Concept Thoracic Duct The thoracic duct begins in the abdomen as the cisterna chyli and conveys lymph from both lower limbs, the entire abdomen, the left half of the thoracic cavity via a thoracic trunk, the left upper limb via a subclavian trunk, and left side of the head and neck via the jugular trunk to the junction of the subclavian and internal jugular veins. Right Lymphatic Duct The right lymphatic duct conveys lymph from the remainder of the body (right side of thorax via a thoracic trunk, right upper limb via a subclavian trunk, right side of head and neck via a jugular trunk) to the junction of the internal jugular and subclavian veins on the right. Lymphatic vessels associated with abdominal viscera generally follow vessels (arteries) and are conveyed to lumbar and intestinal lymphatic vessels/trunks, which lead to the cisterna chyli.

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Pelvis

3

INTRODUCTION The pelvic cavity is the inferior portion of the abdominopelvic cavity and as such has many features and structures in common with the abdominal cavity; many organs and peritoneal relations are continuous between the two. The pelvic cavity contains parts of the urinary system and the internal genitals. The perineum is the area between the thighs and the location of the external genitalia in both sexes.

PELVIS Areas of the pelvis The pelvic cavity is continuous superiorly with the abdominal cavity. Area Structure Pelvic inlet Bounded by: (superior pelvic • Pubic symphysis and aperture) crest • Pectineal line • Arcuate line of the ilium and the ala of each side • Promontory of the sacrum Pelvic outlet

Bounded by: • Pubic symphysis • Ischiopubic ramus and ischial tuberosity • Sacrotuberous ligaments • Coccyx

Significance Collectively the structures that bound the pelvic inlet are known as the linea terminalis or pelvic brim

In the female, the pelvic outlet is larger than in the male to accommodate parturition

(continued)

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Areas of the pelvis (continued) Area Greater pelvis (false pelvis)

Lesser pelvis (true pelvis)

Retropubic space

Retrorectal space

Structure Bounded by: • Lateral—ala of the ilium • Inferior—pelvic inlet • Superior—continuous with abdominal cavity • Anterior—abdominal wall • Posterior—L5–S1 vertebrae Bounded by: • Superior—pelvic inlet (superior pelvic aperture) • Inferior—pelvic outlet and pelvic diaphragm • Lateral—hip bones • Posterior—sacrum and coccyx • Anterior—pubic symphysis Potential, fat-filled area of endopelvic fascia between the pubic symphysis and urinary bladder Potential, fat-filled area of endopelvic fascia between the rectum and sacrum and coccyx

Significance • Superior aspect of the pelvis • Contains abdominal viscera, including the sigmoid colon and parts of the ileum

• Inferior aspect of the pelvis • Contains reproductive and urinary organs, including the urinary bladder, uterus (female), and prostate (male)

Allows for the expansion of the urinary bladder as it fills with urine Allows for the expansion of the rectum during defecation

Clinical Significance Pregnancy The size of the lesser pelvis increases and the pubic symphysis becomes more flexible in pregnant females as hormones cause the pelvic ligaments to relax. Bones of the pelvis (Figure 3-1) Feature Pelvic girdle

Characteristic Basin-shaped group of bones: 2 hip bones and the sacrum

Significance • Transfers weight from vertebral column to lower limbs (continued)

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Bones of the pelvis (continued) Feature

Characteristic

Greater sciatic foramen

Sacrospinous ligament forms greater sciatic notch into foramen

Lesser sciatic foramen

Sacrospinous and sacrotuberous ligaments form foramen

Obturator foramen

Formed by body and ramus of ischium and superior and inferior pubic rami

Significance • Hip bones joined anteriorly by pubic symphysis, joined to sacrum posteriorly at sacroiliac joints Permits passage of piriformis, gluteal vessels, and nerves, sciatic and posterior femoral cutaneous nerves, internal pudendal vessels, pudendal nerve, and nerves to obturator internus and quadratus femoris from the pelvis to the gluteal region Permits passage of the tendon of obturator internus and the internal pudendal vessels and pudendal nerve as they wrap around the ischial spine to enter the perineum • Covered by obturator membrane • A deficiency in the obturator membrane—the obturator canal: permits passage of obturator vessels and nerves between the pelvis and lower limb • Cup-shaped articular cavity on lateral aspect of hip bone • Head of femur articulates here • Acetabular notch bridged by transverse acetabular ligament to complete cup

• Formed by contributions from the ilium, ischium, and pubis • Deficient inferiorly as the acetabular notch Inferior borders of ischiopubic Formed by both Pubic arch rami form subpubic angle, ischiopubic rami, which is typically ⬍70⬚ in males which meet at the and ⬎80⬚ in females pubic symphysis Hip Bones—formed by the fusion of the ilium, ischium, and pubis • Expanded upper portion of ilium Ala Ilium • Superior border is the iliac crest • Posterior gluteal surface bears 3 lines: the anterior, middle, Acetabulum

(continued)

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Bones of the pelvis (continued) Feature

Description

Body

Arcuate line

Iliac crest

Anterior superior iliac spine

Posterior superior iliac spine

Anterior inferior iliac spine Posterior inferior iliac spine Iliac fossa

Greater sciatic notch Ischium

Body

Ramus Ischial tuberosity

Significance and posterior gluteal lines that serve as attachments for muscles of the gluteal region • Anterior surface—iliac fossa • The smaller inferior portion of the ilium • Forms part of acetabulum • Junction of the body of the ilium and body of the ischium • Part of linea terminalis • Superior border of ala • Attachment for abdominal, back, and lower limb muscles • Located between the anterior and posterior superior iliac spines • Anterior end of iliac crest • Attachment for fascia lata, tensor of fascia lata, sartorius, and inguinal ligament • Posterior end of iliac crest • Attachment for multifidus • Site of skin dimples • Marks S2 vertebral level and inferior end of dural sac Attachment for rectus femoris Superior border of greater sciatic notch • Depression on anterior aspect of ala • Proximal attachment for iliacus Between posterior inferior iliac spine and ischial spine • Forms part of acetabulum • Ischial spine and tuberosity project from body Articulates with inferior ramus of pubis • Projection from body of ischium • Attachment for adductor magnus, the hamstrings, and the sacrotuberous ligament (continued)

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Bones of the pelvis (continued) Feature

Pubis

Description

Significance

Ischial spine

• Projection from body • Attachment for superior gemellus, coccygeus, levator ani, and sacrospinous ligament—which converts the greater sciatic notch into a foramen • Forms superior border of lesser sciatic notch

Body

Forms part of acetabulum

Superior ramus

• Articulates with contralateral superior ramus • Pubic tubercle projects from superior ramus • Contributes to obturator foramen

Pubic tubercle

• Projection from superior ramus • Attachment for inguinal ligament and inferior crus of superficial inguinal ring

Pectin pubis

• Ridge along superior ramus extending laterally from pubic tubercle • Attachment for lacunar ligament and conjoint tendon

Inferior ramus

Contributes to obturator foramen

The gluteal-aspect (posterior) of the bones in this table is described with the skeletal sections of the lower limb and back.

Additional Concept Greater Sciatic Foramen The greater sciatic foramen is considered an exit from the pelvis. Of the structures passing out of the pelvis via the foramen, only the superior gluteal vessels and nerves pass superior to the piriformis, all other structures pass inferior to this landmark muscle. Ischiopubic Ramus The ramus of the ischium and the inferior ramus of the pubis are collectively known as the ischiopubic ramus.

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Fifth lumbar vertebra

Sacrum

Iliac crest Anterior superior iliac spine Anterior inferior iliac spine

Coccyx

Ischical spine

Neck of femur

Lesser trochanter

Body of pubis

Symphysis of pubis

Ischial tuberosity

Obturator foramen

FIGURE 3-1. Bones of the pelvis radiograph. (From Dudek RW, Louis TM. High-Yield Gross Anatomy. 3rd ed. Baltimore: Lippincott Williams & Wilkins; 2008:211.)

Clinical Significance Sex Differences in the Pelves The pelves differ between the sexes: the female pelvis is specialized for parturition. The female pelvis is lightweight, wide, and shallow, with an oval pelvic inlet and larger pelvic outlet and subpubic angle relative to the male pelvis. Minimum diameters of the pelvis are important in obstetrics. The obstetric “true” conjugate—the distance between the posterior aspect of the pubic symphysis and the sacral promontory should be ⬎11 cm for vaginal delivery. Joints of the pelvis (Figure 3-1) Joint Sacroiliac

Type • Anterior part: synovial

Articulation Sacrum suspended between iliac bones

Structure • Joint strengthened by anterior, posterior, and interosseous sacroiliac ligaments

(continued)

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Joints of the pelvis (continued) Joint

Type • Posterior part: fibrous

Articulation

Structure • Sacrotuberous and sacrospinous ligaments provide resilient support during times of sudden weight increases (e.g., jumping)

Pubic symphysis

Cartilaginous

Between bodies of pubic bones

• Interpubic disc located between bones • Joint strengthened by superior and inferior pubic ligaments; also strengthened by tendons of rectus abdominis and external oblique

The joints associated with the vertebral column are described with the back (see Chapter 4). Peritoneum of the pelvis (Figure 3-6) The peritoneum lining the greater sac of the abdomen continues into the pelvis; it reflects onto the organs of the pelvis creating pouches and fossae. Feature Female Supravesical fossa

Description

Significance

Between anterior abdominal wall and urinary bladder

Vesicouterine pouch

Between urinary bladder and uterus

Rectouterine pouch

Between uterus and rectum

Reflection of peritoneum from anterior abdominal wall onto superior surface of urinary bladder • Allows for expansion of urinary bladder • Reflection of peritoneum from urinary bladder onto uterus • Allows for expansion of uterus and urinary bladder • Potential site for fluid accumulation during pathologic processes • Reflection of peritoneum from uterus to rectum (continued)

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Peritoneum of the pelvis (continued) Feature

Male Supravesical fossa

Rectovesical pouch

Description

Significance • Allows for expansion of rectum and uterus • Potential site for fluid accumulation during pathologic processes

Between anterior abdominal wall and urinary bladder

Reflection of peritoneum from anterior abdominal wall onto superior surface of urinary bladder • Allows for expansion of urinary bladder • Reflection of peritoneum from urinary bladder onto rectum • Allows for expansion of rectum and urinary bladder • Potential site for fluid accumulation during pathologic processes

Between urinary bladder and rectum

Fascia of the pelvis (Figure 3-6) Fascia/Connective Tissue Pelvic fascia

Significance/Structure • Inferior continuation of endoabdominal fascia • Between parietal peritoneum and muscular body wall Parietal layer of pelvic Membranous layer of pelvic fascia that lines the fascia muscles of the pelvic walls Visceral layer of pelvic Membranous layer of pelvic fascia that invests the fascia organs of the pelvis as their adventitial layer Tendinous arch of Anteroposterior oriented bilateral thickening of pelvic pelvic fascia fascia formed at points of reflection between the parietal and visceral layers of pelvic fascia (just lateral to where organs penetrate pelvic floor) Puboprostatic ligament Anterior subdivision of tendinous arch in the male that connects the prostate to the pubis Pubovesical ligament Anterior subdivision of tendinous arch in the female that connects the neck of the bladder to the pubis Layer of fascia connecting the visceral and parietal Endopelvic fascia layers of pelvic fascia of varying consistency (continued)

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Fascia of the pelvis (continued) Fascia/Connective Tissue Transverse cervical (cardinal) ligament

Rectovesical septum Prostatic sheath

Significance/Structure • Condensed layer of endopelvic fascia in the female that provides the primary support for the uterus • Connects lateral wall of pelvis with the cervix of the uterus Condensed layer of endopelvic fascia in the male between the bladder and prostate and the rectum • Formed by the visceral layer of pelvic fascia • Surrounds fibrous capsule of the prostate • Continuous anteriorly with the puboprostatic ligaments and posteriorly with the rectovesical septum

Muscles of the pelvis (Figures 3-2, 3-3, and 3-6) Proximal Attachment Obturator membrane, ilium, and ischium Sacrum Piriformis (S2–S4 segments), sacrotuberous ligament, margin of greater sciatic notch Pubis, Levator ani tendinous (iliococcygeus, pubococcygeus arch of obturator [largest part] and puborectalis) internus and ischial spine

Distal Attachment Greater trochanter of femur

Coccygeus

Sacrum and coccyx

Muscle Obturator internus

Ischial spine

Innervation Nerve to obturator internus (L5–S2) S1–S2

Perineal Pudendal body, coccyx, and nerve to anococcygeal levator ani ligament, walls of prostate, vagina, rectum and anal canal

S4–S5

Main Actions Laterally rotates thigh, holds femur in acetabulum Laterally rotates and abducts thigh; holds femur in acetabulum

• Part of pelvic diaphragm • Supports pelvic viscera • Puborectalis part forms sling around anorectal junction— responsible for fecal continence Part of pelvic diaphragm • Supports pelvic viscera

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Additional Concept Pelvic Diaphragm The pelvic diaphragm is the funnel-shaped floor of the pelvis, formed by the levator ani and coccygeus. The levator ani is subdivided based on attachment into iliococcygeus, pubococcygeus, and puborectalis from superior to inferior. Obturator Fascia A thickening of the fascia of the obturator internus—the obturator fascia on the medial surface of the muscle— forms the tendinous arch of levator ani, which serves as an attachment for levator ani. Sacral Plexus The sacral plexus sits on the muscular “bed” of the piriformis.

Clinical Significance Trauma to the Pelvic Floor The muscles forming the floor of the pelvis may be injured during childbirth. Trauma to the pubococcygeus, the main part of the levator ani or the nerves supplying it, may lead to urinary incontinence. Nerves of the pelvis (Figures 3-2, 3-3, and 3-6) The lumbosacral trunk conveys fibers from the L4–L5 spinal cord levels to the sacral plexus (S1–S4). The sacral plexus innervates pelvic structures, the perineum, and the lower limb; it is formed of anterior rami. Nerve Sacral Plexus Sciatic

Origin

Structures Innervated

L4–S3

Pudendal

S2–S4

Superior gluteal

L4–S1

Inferior gluteal

L5–S2

Supplies hip joint, leg, foot and posterior compartment of the thigh • Supplies perineal musculature, sphincter urethrae, and external anal sphincter • Sensory to skin covering external genitalia Supplies gluteus medius and minimus and tensor of fascia lata Supplies gluteus maximus (continued)

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Nerves of the pelvis (continued) Nerve Origin Structures Innervated Nerve to piriformis S1–S2 Supplies piriformis Supplies quadratus femoris and inferior Nerve to quadratus L4–S1 gemellus femoris Nerve to obturator L5–S2 Supplies obturator internus and internus superior gemellus Nerve to levator ani S3–S4 Supplies levator ani and coccygeus Sensory to inferior aspect of buttock Posterior femoral S2–S3 and posterior aspect of thigh cutaneous Coccygeal Plexus—sparse fibers from lower sacral and coccygeal spinal cord levels that inconsistently provide sensory and motor innervation to nearby regions and structures. Autonomic Innervation of the Pelvis Sacral levels of Fibers join the hypogastric, pelvic, Sympathetic the sacral, and coccygeal plexuses and sympathetic follow arteries to their targets— trunks convey arteries, urinary bladder, prostate, postsynaptic seminal glands, uterus, vagina, and sympathetic genitals fibers, and sacral splanchnic nerves to plexuses in the pelvis S2–S4 contain Fibers join the hypogastric and pelvic Parasympathetic presynaptic plexuses and follow arteries to their parasympathe- targets—urinary bladder, rectum, and tic fibers that genitals, where they synapse in the are conveyed wall of the organ via pelvic splanchnic nerves to plexuses in the pelvis The pelvic pain line is indicated by Visceral afferents Inferior to pelvic pain line: the peritoneum as it drapes into the convey pelvis—structures in contact with the sensation to peritoneum are above the pain line; S2–S4 levels structures inferior to the peritoneum via pelvic are below the pain line splanchnics; superior to pelvic pain line: convey sensation to thoracic and lumbar spinal cord levels

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Clinical Significance Compression of the Sacral Plexus The fetal head may compress branches of the sacral plexus during pregnancy and childbirth, producing pain in the lower limbs and back. Mnemonic Pudendal Nerve Roots Pudendal and parasympathetic spinal cord levels: S2, S3, and S4 keep the genitals off the floor.

Psoas major Iliolumbar artery Internal iliac artery and vein Lumbosacral trunk Obturator nerve Superior gluteal nerve Sciatic nerve

Sympathetic trunk and ganglion Rami communicantes Lateral sacral artery Nerves to piriformis Sacral plexus Coccygeus S4

Inferior gluteal artery Pudendal nerve Pelvic splanchnic nerves

S5

Coccygeal plexus

Medial view from left

FIGURE 3-2. Nerves of the pelvis. Somatic nerves (sacral and coccygeal nerve plexuses) and the pelvic (sacral) part of the sympathetic trunk are shown. Although located in the pelvis, most of the nerves seen here are involved with the innervation of the lower limb rather than the pelvic structures. (From Moore KL, Dalley AF. Clinically Oriented Anatomy. 5th ed. Baltimore: Lippincott Williams & Wilkins; 2006:380.)

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Vasculature of the pelvis (Figures 3-2, 3-3, 3-4, and 3-6) Artery Internal iliac Anterior division Posterior division Umbilical

Origin Common iliac Internal iliac

Anterior division

Obturator Superior vesical Inferior vesical Middle rectal Superior gluteal Inferior gluteal Internal pudendal Uterine/ vaginal

Umbilical

Iliolumbar

Posterior division

Anterior division

Description Supplies pelvis, gluteal region, thigh, and perineum Supplies pelvic viscera and medial compartment of the thigh Supplies walls of pelvis and gluteal region • Gives rise to superior vesical and occasionally uterine and vaginal arteries • Obliterated distal part forms medial umbilical ligaments Supplies superior aspect of medial compartment of thigh Supplies urinary bladder Supplies urinary bladder, prostate, seminal gland, and ureter Supplies rectum, seminal gland, and prostate Supplies superior aspect of gluteal region Supplies inferior aspect of gluteal region Supplies perineum • May arise from anterior division or umbilical; may branch from common trunk • Supply uterus and vagina, respectively Supplies iliacus, psoas, quadratus lumborum, and vertebral canal Supplies piriformis and vertebral canal

Lateral sacral Supply testes and ovaries Abdominal Gonadal (testicular aorta or ovarian) Veins—veins draining to caval system generally follow arteries to terminate in the internal iliac vein; veins following portal system contribute to the inferior mesenteric vein

Additional Concept Venous Drainage Venous drainage generally parallels arterial supply.

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Common iliac artery Internal iliac artery

Iliolumbar artery Lateral sacral artery

External iliac artery Obturator artery

Medial umbilical ligament (obliterated umbilical artery) Superior vesical arteries

Superior Inferior

Gluteal arteries

Inferior vesical artery Internal pudendal artery Pudendal nerve Middle rectal artery

A Common iliac artery Internal iliac artery External iliac artery Obturator artery

Iliolumbar artery Lateral sacral artery Superior Inferior

Gluteal arteries

Uterine artery Medial umbilical ligament (obliterated umbilical artery) Superior vesical arteries

Internal pudendal artery Pudendal nerve Middle rectal artery Vaginal artery

B

FIGURE 3-3. Arteries of the pelvis. The arteries of the male pelvis (A) and the female pelvis (B) are shown. Anterior divisions of the internal iliac arteries usually supply most of the blood to pelvic structures. The arteries are internal (lie medial) to the nerves making up the sacral plexus. (From Moore KL, Dalley AF. Clinically Oriented Anatomy. 5th ed. Baltimore: Lippincott Williams & Wilkins; 2006:386.)

Lymphatics of the pelvis Structure Urinary bladder

Description Vessels accompany

Drainage • Superior aspect: external iliac nodes • Inferior aspect: internal iliac nodes (continued)

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Lymphatics of the pelvis (continued) Structure Ureters

Urethrae

Seminal glands Prostate Penis

Description arteries— generally structures drain into external and internal iliac nodes, which drain into common iliac nodes to the lumbar nodes

Drainage Vessels drain to internal and external common iliac and lumbar nodes owing to their long course • Male: vessels from prostatic and membranous portions drain to internal iliac nodes, whereas those from the penile urethra drain to the deep inguinal nodes • Female: vessels drain to the sacral and internal iliac nodes External and internal nodes Internal iliac and sacral nodes Superficial and deep inguinal and external and internal iliac nodes • Superior aspect: internal and external iliac nodes • Middle aspect: internal iliac nodes • Inferior aspect: sacral and common iliac nodes • Drainage from the external vaginal orifice to superficial inguinal nodes • Fundus: lumbar nodes • Body: external iliac nodes • Cervix: internal iliac and sacral nodes Lumbar nodes Superficial inguinal nodes

Vagina

Uterus

Ovaries Vulva

URINARY BLADDER Structure of the urinary bladder (Figures 3-3 and 3-6) The bladder is a hollow, muscular organ that serves as reservoir for urine until it is voided. When empty, it is located entirely within the lesser pelvis; when full, it may extend through the extraperitoneal fascial plane superiorly as high as the umbilicus. Structure Parts Body

Description

Significance

Main part, between the apex and fundus

• In males—related to the rectum • In females—related to the vagina (continued)

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Structure of the urinary bladder (continued) Structure Apex

Description Part directed toward the pubic symphysis

Neck

Inferior-most part

Fundus

Convex, posteriorlydirected part

Features Detrusor muscle

Internal urethral sphincter

Internal urethral orifice

Urinary trigone

• Composes the muscular part of the bladder wall • Internal wall covered with rugae to allow for expansion Formed of circularly disposed smooth muscles fibers

• Internal opening of the urethra • Located at inferior “corner” of urinary trigone Smooth inferoposterior aspect of bladder wall

Significance • Anterior-most aspect • Part from which the urachus—embryologic shunt for urine, originates Anchored in place by the lateral ligaments of the bladder and the tendinous arch of pelvic fascia • Also known as the base • Location of the ureters as they enter the bladder Innervated by the parasympathetics S2–S4, causes constriction of wall and expulsion of urine • Located near neck of bladder • Contract during ejaculation to prevent semen from entering bladder Radially arranged smooth muscle fibers assist in opening the sphincter to expel urine 3 corners of trigone: Inferior—internal urethral orifice and 2 superior— ureteric orifices

Additional Concept Peritoneal Relations The urinary bladder is covered only on its superior surface with peritoneum; the remainder is covered with loose connective tissue (vesical fascia). The bladder is relatively free except at the neck where it is held in place by the tendinous arch of the pelvis. Median Umbilical Fold The median umbilical ligament (vestige of the fetal urachus) is covered by peritoneum to form the median umbilical fold.

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Vasculature of the urinary bladder Artery Origin Superior vesical Umbilical Inferior vesical

Internal iliac

Vaginal

Uterine (sometimes via common trunk), umbilical, or internal iliac Internal iliac

Obturator Inferior gluteal

Description Supply anterior and superior aspects Males: supply posterior and inferior aspects Females: supply posterior and inferior aspects May supply branches to bladder

Additional Concept Venous Drainage Venous drainage generally parallels arterial supply to end in the internal iliac vein. Nerves of the urinary bladder Nerve Parasympathetic

Sympathetic

Visceral afferents

Origin S2–S4, conveyed via pelvic splanchnic nerves to pelvic plexuses Presynaptics originate from the intermediolateral cell column of the spinal cord and travel in the sympathetic trunks and splanchnic nerves to reach pelvic plexuses Bladder wall

Structures Innervated Motor to detrusor, inhibitory to internal urethral sphincter

Motor to internal urethral sphincter

• Senses stretching of bladder wall, impulses conveyed to spinal cord via pelvic splanchnics from most of bladder • Superior part of bladder is superior to pelvic pain line so impulses are conveyed via sympathetic system

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URETHRAE Structure of the urethrae (Figures 3-3 and 3-6) The urethrae extend from the internal urethral orifice of the urinary bladder to the external urethral orifice in both sexes. They function to convey urine from the urinary bladder to the outside world. Structure Female urethra

Male urethra

Description • External urethral orifice located in the vestibule of the vagina • Passes through pelvic and urogenital (external urethral sphincter) diaphragms • External urethral orifice located on tip of glans penis • Passes through pelvic and urogenital (external urethral sphincter) diaphragms

Significance • Located anterior to the vagina • Urethral glands open along length • Paraurethral glands open near external urethral orifice • Common route for urine and semen • Divided into 4 parts: 1. Intramural (preprostatic) 2. Prostatic 3. Membranous 4. Penile (spongy)

Clinical Significance Catheterization The short, distensible female urethra allows for easy passage of catheters into the bladder and provides an easy route for bacterial infection of the bladder. Vasculature of the urethrae Artery Female Internal pudendal Vaginal Male Inferior vesical Middle rectal Internal pudendal

Origin

Description

Anterior division Supplies urethra and perineum of internal iliac Supplies urethra and vagina Anterior division Supply intramural and prostatic parts via of internal iliac prostatic branches

Supplies membranous and penile parts

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Additional Concept Venous Drainage Venous drainage generally parallels arterial supply. Nerves of the urethrae Nerve Parasympathetic

Sympathetic

Visceral afferents—both sexes Somatic afferents—both sexes

Origin Presynaptics originate in spinal cord levels S2–S4, conveyed via pelvic splanchnic nerves to pelvic plexuses Presynaptics originate from the intermediolateral cell column of the spinal cord and travel in the sympathetic trunks and, finally, sacral splanchnic nerves to reach pelvic plexuses Urethra

Structures Innervated Inhibitory to internal urethral sphincter

Motor to internal urethral sphincter

Impulses conveyed to spinal cord via pelvic splanchnics Pain and general tactile impulses conveyed to spinal cord via pudendal nerve

FEMALE GENITALIA Internal genitalia of the female (Figures 3-3 and 3-4) Structure Vagina Overall

Description

Significance

• Extends from the uterus to • Vaginal vestibule—cleft the vaginal vestibule between labia minora • Continuous superiorly with • Forms inferior part of birth cervical canal at the canal, route for menses, external os of the uterus and receives erect penis • Vaginal fornices (anterior, during copulation lateral, and posterior) • Relations: surround uterine cervix • Anterior—bladder • Posterior—rectum • Lateral—levator ani (continued)

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Internal genitalia of the female (continued) Structure Vessels

Innervation

Uterus Overall

Vessels

Description • Arterial supply: uterine, vaginal, and internal pudendal • Venous drainage: via vaginal plexus to uterovaginal venous plexus to internal iliac veins • Motor: superior aspect— visceral, inferior aspect— somatic • Sensory: superior aspect— visceral, inferior aspect— somatic

• Structure: • Fundus: superior to uterine tubes • Body: main part, contains uterine cavity • Isthmus: narrow region superior to cervix • Cervix: possesses cervical canal with superior and inferior openings: the internal and external os • Relations: • Anterior: bladder with intervening vesicouterine pouch • Posterior: rectum with intervening rectouterine pouch • Arterial supply: uterine and ovarian • Venous drainage: via uterine plexus to uterovaginal plexus to internal iliac veins

Significance Origin of arteries: anterior division of internal iliac

• Visceral: uterovaginal nerve plexus contains sympathetics from the intermediolateral cell column, conveyed via the sympathetic chain and parasympathetics from S2–S4 spinal cord levels conveyed via pelvic splanchnics, visceral afferents travel with pelvic splanchnics • Somatic: pudendal nerve • Thick-walled, muscular organ • Uterine cervix projects into superior aspect of vagina where it is surrounded by the vaginal fornices • The uterus is supported by ligaments (condensations of pelvic fascia) near the cervix—the transverse cervical (cardinal) and uterosacral ligaments

Origin of arteries: anterior division of internal iliac

(continued)

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Internal genitalia of the female (continued) Structure Innervation

Uterine Tubes Overall

Vessels

Innervation

Description Innervation is from uterovaginal plexus

Significance Uterovaginal nerve plexus contains sympathetics from the intermediolateral cell column, conveyed via the sympathetic chain and parasympathetics from S2–S4 spinal cord levels conveyed via pelvic splanchnics, visceral afferents for pain travel with sympathetics above the pelvic pain line and with pelvic splanchnics below the pelvic pain line

• Bilateral; extend from the • Infundibulum— junction of the fundus and funnel-shaped end near body of the uterus to open ovary, possesses fimbriae: into the peritoneal cavity finger-like processes that adjacent to the ovaries envelope the medial pole • Divided into infundibulum, of the ovary ampulla, isthmus, and • Ampulla—longest part, uterine parts normal site of fertilization • Isthmus—part that enters the uterus • Uterine part—intramural • Arterial supply: ovarian Origin of arteries: abdominal arteries aorta • Venous drainage: empties into the ovarian veins and the uterovaginal venous plexus Innervation is from uterine Contain sympathetics from and pelvic plexuses the intermediolateral cell column, conveyed via the sympathetic chain and parasympathetics from S2–S4 spinal cord levels conveyed via pelvic splanchnics, visceral afferents travel with sympathetics as the uterine tubes are above the pelvic pain line, some visceral afferents travel with pelvic splanchnics to mediate reflexes (continued)

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Internal genitalia of the female (continued) Structure Ovaries

Description

Significance

Overall

• Located along lateral walls • Not covered by peritoneum of pelvis • The oocyte is ovulated into • Held in relatively stable the peritoneal cavity position by the meso• Fimbriae of the uterine varium, suspensory tubes and the ciliated ligament of the ovary, lining of the uterine tubes and the ligament of typically guide the oocyte the ovary into the ampulla of the uterine tube

Vessels

• Arterial supply: ovarian • Origin: abdominal aorta arteries • The pampiniform plexus • Venous drainage: small of veins forms a pair of veins drain to a pampiniovarian veins, the right form venous plexus located ovarian vein empties within the broad ligament into the inferior vena cava, whereas the left drains into the left renal vein

Innervation

Innervation is from uterine and pelvic plexuses

Contain sympathetics from the intermediolateral cell column, conveyed via the sympathetic chain and parasympathetics from S2–S4 spinal cord levels conveyed via pelvic splanchnics, visceral afferents travel with sympathetics as the uterine tubes are above the pelvic pain line, some visceral afferents travel with pelvic splanchnics to mediate reflexes

Additional Concept Uterus The uterus is typically anteverted (tipped anteriorly relative to the vagina) and anteflexed (body is flexed anteriorly relative to the cervix), but variations in degree and position are common. The uterus is covered by peritoneum, which extends laterally off the uterus to the walls of the pelvis as the broad ligament. The broad ligament conveys uterine neurovascular elements between its layers and contains the ovaries and

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uterine tubes. The suspensory ligament of the ovary is a superolateral extension of the broad ligament from the ovary that conveys the ovarian vessels. The ligament of the ovary is found within the broad ligament and connects the ovary to the uterine body, whereas the round ligament of the uterus, also found within the broad ligament, projects from the uterine body through the inguinal canal to terminate as connective tissue septa in the labia majora. A posterior extension of broad ligament invests the ovary— the mesovarium, an extension of the broad ligament invests the uterine tube—the mesosalpinx. Inferior to the mesosalpinx the broad ligament is referred to as the mesometrium. Embryologic Origins The ligament of the ovary and the round ligament of the uterus are vestiges of the embryologic ovarian gubernaculums and are the equivalent of the very short scrotal ligament in the male. External genitalia of the female (Figure 3-4) Structure Description Significance Mons Pubis, Labia Major, and Labia Minora Overall • Mons pubis and labia The labia minora are majora are prominent, connected anteriorly, the fatty, pubic hair covered posterior aspect of this eminences surrounding connection forms the the pudendal cleft frenulum of the clitoris, • The labia minora are thin, whereas the anterior portion fat-free folds of skin that forms the prepuce of the enclose the vaginal vesti- clitoris, posteriorly they are bule united to form the frenulum of the labia minora Vessels • Arterial supply: labial • Origin of arteries: internal branches pudendal • Venous drainage: parallels • During sexual arousal— arterial supply enlarge as a result of increased blood in underlying structures Innervation Pudendal Pudendal and its branches (anterior and posterior labial) are chief source of sensory innervation (continued)

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External genitalia of the female (continued) Structure Clitoris Overall

Description Parts: root and body; composed of 2 crura made of 2 erectile cylinders—the corpora cavernosa and the glans of the clitoris

Significance

• The corpora cavernosa diverge posteriorly to form crura that attach to ischiopubic rami for support and are invested by the ischiocavernosus muscles • The glans is the most sensitive part of the heavily innervated clitoris Vessels • Arterial supply: clitoral • Origin of arteries: internal branches pudendal • Venous drainage: parallels • Sexual arousal causes arterial supply engorgement and enlargement from increased arterial supply and decreased venous return Innervation Pudendal and uterovaginal • Pudendal branches (dorsal plexus nerve of the clitoris) provide somatic sensation • Parasympathetics from uterovaginal plexus cause erection Bulbs of the Vestibule and Vestibular Glands Overall • Bulbs of the vestibule are • Bulbospongiosus invests masses of erectile tissue the bulbs of the vestibule underlying the labia majora • The vestibular glands • Vestibular glands lie post(greater and lesser) secrete erior to the bulbs mucus during sexual arousal to moisten the vestibule Vessels • Arterial supply: branches • Origin of arteries: internal of the internal pudendal pudendal • Venous drainage parallels • Sexual arousal causes arterial supply engorgement and enlargement of the bulbs of the vestibule from increased arterial supply and decreased venous return Innervation Uterovaginal plexus Parasympathetics from uterovaginal plexus cause erection and increased secretion from the glands

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Ovarian artery and vein Ampulla

Uterine tube Isthmus

Uterus

Ligament of ovary

Infundibulum Fimbriae Ovary Ureter Uterine vein Uterine artery Ascending branch of uterine artery

Vaginal artery and vein Vaginal venous plexus

A

Vagina

Internal pudendal artery

Uterine cavity Ampulla of uterine tube

Vagina

B

C

FIGURE 3-4. Female pelvis. A: Diagram of the arterial supply and venous drainage of the ovaries, uterine tubes, uterus, and vagina. B: Anteroposterior radiograph of the female pelvis after injection of a radiopaque compound into the uterine cavity (hysterosalpingography). C: Diagram of the female genitalia. (From Dudek RW, Louis TM. High-Yield Gross Anatomy. 3rd ed. Baltimore: Lippincott Williams & Wilkins; 2008:185.)

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Additional Concept Collectively, the external genitalia of the female are referred to as the vulva or pudendum. The labia majora enclose a space—pudendal cleft, which contain the labia minora and vaginal vestibule, whereas the labia minor enclose the vaginal vestibule, which contains the vaginal orifice, external urethral orifice (with openings of the ducts of the paraurethral glands on either side), and openings of the vestibular glands.

MALE GENITALIA Internal genitalia of the male (Figures 3-3 and 3-5) Structure Description Ductus Deferens (2) Overall Begins in scrotum at tail of epididymis; ends by joining duct of seminal gland to form ejaculatory duct

Vessels

Innervation

Significance • Proximal continuation of epididymis • Ascends as part of spermatic cord; possesses an ampulla—an expansion near its distal end Origin of arteries: superior vesical artery

• Arterial supply: artery to the ductus deferens • Venous drainage parallels arteries Innervation is from the Contains sympathetics from pelvic plexus the intermediolateral cell column, conveyed via the sympathetic chain and sacral splanchnics and parasympathetics from S2–S4 spinal cord levels conveyed via pelvic splanchnics

Seminal Glands Overall • Located between urinary • Secrete a thick alkaline bladder and rectum— fluid that contributes to separated from it by the semen rectovesical pouch • Duct joins with ductus deferens to form ejaculatory duct Vessels • Arterial supply: Origin of arteries: inferior small branches vesical and middle rectal • Venous drainage parallels arteries (continued)

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Internal genitalia of the male (continued) Structure Innervation

Description Innervation is from the pelvic plexus

Ejaculatory Ducts Overall Formed by the union of the ductus deferens and the duct of the seminal gland

Vessels

Innervation

Prostate Overall

• Arterial supply: artery to the ductus deferens • Venous drainage is to prostatic and vesical venous plexuses Innervation is from the pelvic plexus

Significance Contains sympathetics from the intermediolateral cell column, conveyed via the sympathetic chain and parasympathetics from S2–S4 spinal cord levels conveyed via pelvic splanchnics • Open near the prostatic utricle in the prostatic urethra • Secrete fluid from the seminal gland and sperm from the ductus deferens Origin of arteries: superior (or inferior) vesical artery

Contains sympathetics from the intermediolateral cell column, conveyed via the sympathetic chain and parasympathetics from S2–S4 spinal cord levels conveyed via pelvic splanchnics

Lobes: • Surrounds prostatic urethra • Lateral (right and left)— Possesses fibrous capsule— largest, located on sides fibrous capsule of the of prostatic urethra prostate, which invests • Isthmus—anterior to nerves and vessels supplyurethra, muscular continua- ing the gland and is tion of internal urethral surrounded by the visceral sphincter layer of pelvic fascia— • Posterior—posterior to prostatic sheath, puboprosurethra, palpable via tatic ligaments, and the rectum rectovesical septum • Middle—between urethra • Prostatic ducts (20–30) and ejaculatory ducts; open into prostatic sinuses enlargement may interfere on the side of the seminal with urination colliculus in the prostatic urethra where they convey a milky alkaline secretion (continued)

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Internal genitalia of the male (continued) Structure

Description

Vessels

• Arterial supply: prostatic • Origin of arteries: internal arteries pudendal, middle rectal, • Venous drainage is to proand inferior vesical static plexus associated • Venous plexus drains with the fibrous capsule into internal iliac veins and communicates with internal vertebral and vesical venous plexuses— potential routes for metastasis

Significance

Innervation

Innervation is from the pelvic Contains sympathetics from plexus the intermediolateral cell column, conveyed via the sympathetic chain and parasympathetics from S2–S4 spinal cord levels conveyed via pelvic splanchnics Bulbourethral Glands (2) Overall

Lie posterolateral to the membranous urethra within the external urethral sphincter

The ducts of the bulbourethral glands pierce the perineal membrane to open into the bulbous part of the penile urethra, into which they secrete a mucus-like secretion

Vessels

• Arterial supply: perineal Origin of arteries: internal branches pudendal • Venous drainage parallels arterial supply

Innervation

Innervation is from the pelvic plexus

Contains sympathetics from the intermediolateral cell column, conveyed via the sympathetic chain and parasympathetics from S2–S4 spinal cord levels conveyed via pelvic splanchnics

Clinical Significance Vasectomy The vasectomy (ligation of the ductus deferens) is a common method of sterilization in the male.

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Spermatic cord Testicular vein (pampiniform venous plexus) Ductus deferens Efferent ductules

Testicular artery

Rete testis in mediastinum of testis Seminiferous tubule head Epididymis body tail

Straight tubule Septum Visceral layer o tunica vaginalis Cavity of tunica vaginalis Parietal layer of tunica vaginalis Tunica albuginea

A

Lateral view

Urethral crest Prostate Openings of prostatic ducts into prostatic sinuses Opening of ejaculatory duct Bulbourethral glands

Prostatic utricle Seminal colliculus

External urethral sphincter Perineal membrane

B FIGURE 3-5. A: Testis and (B) prostate. (From Dudek RW, Louis TM. High-Yield Gross Anatomy. 3rd ed. Baltimore: Lippincott Williams & Wilkins; 2008:196.)

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Enlargement of the Prostate Hypertrophy of the prostate is common after middle age and can interfere with urination. The seminal glands and prostate are easily palpable from the rectum. Cancer of the prostate affects 1 in 10 males. External genitalia of the male (Figures 3-5 and 3-6) Structure Description Penile Urethra Overall • Distal to the membranous urethra • Begins at perineal membrane, ends at external urethral orifice • Expansion at proximal end in bulb of penis—the intrabulbar fossa and at distal end—the navicular fossa Vessels • Arterial supply: dorsal artery of the penis • Venous supply: parallels arterial supply Innervation Pudendal nerve

Testes Overall

• Located in scrotum • Outer layer—tunica albuginea surrounded by tunica vaginalis • An expansion of tunica albuginea on posterior aspect of testis forms mediastinum testis, which sends septa into testicle to form lobules • Lobules contain seminiferous tubules that join posteriorly as straight tubules that traverse the mediastinum as the rete testis

Significance • Membranous urethra traverses the deep perineal pouch and is surrounded by the external urethral sphincter • Bulbourethral glands open into proximal part, whereas urethral glands open along length to lubricate urethra Origin of arteries: internal pudendal artery

Pain and general tactile impulses conveyed to spinal cord via pudendal nerve • Produce sperms and testosterone • Tunica vaginalis is an extension of peritoneum, divided into visceral layer on surface of testis and parietal layer lining scrotal wall • Seminiferous tubules are site of sperm production • Leydig cells in interstitial tissue are site of testosterone production • Rete testis convey sperm to head of epididymis via efferent ductules (continued)

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External genitalia of the male (continued) Structure Vessels

Innervation

Penis Overall

Vessels

Innervation

Description Significance • Arterial supply: testicular • Origin of arteries: abdominal (form part of spermatic aorta cord) • Pampiniform plexus helps • Venous drainage: pampiniwith temperature regulation form plexus for sperm formation and forms the left (empties into left renal vein) and right (empties into inferior vena cava) testicular veins Parasympathetic and • Parasympathetics: from sympathetic fibers from vagus testicular plexus • Sympathetics: from thoracic spinal cord and paravertebral chain • Parts: root, body, and glans • The dorsal corpora caver• Formed of 3 cylinders of nosa are surrounded by a erectile tissue: 1 corpus thick tunica albuginea that spongiosum and make for rigid erection,they 2 corpora cavernosa separate into 2 crura proxithat are surrounded by the mally and fuse with the deep fascia of the penis ischiopubic rami for support • The ventrally located corpus spongiosum is traversed by the penile urethra and remains less rigid • Arterial supply: deep and • Origin of arteries: internal dorsal arteries of the penis pudendal • Venous drainage: blood • Deep dorsal vein conveys from the erectile tissues blood to the prostatic drains to deep dorsal vein plexus of veins of penis, blood from remaining penile structures drains via the superficial dorsal veins to the external pudendal vein Receives parasympathetic, Contain sympathetics from sympathetic and sensory the intermediolateral cell fibers column, conveyed via the sympathetic chain and parasympathetics from S2–S4 spinal cord levels conveyed via pelvic splanchnics, afferents are carried by the dorsal nerve of the penis, a branch of the pudendal nerve

The scrotum is an outpocketing of the anterior abdominal wall and is presented in Chapter 2.The testicles are presented with the male external genitalia.

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Common iliac artery and vein Internal iliac artery and vein

External iliac artery and vein

Ureter Sciatic nerve

Cut edge of peritoneum

Rectovesical pouch

Ductus deferens Urinary bladder

Seminal gland

Retropubic space

Rectum (ampulla) Internal urethral orifice Ejaculatory duct

Prostatic urethra Deep dorsal vein of penis

Prostate

External urethral sphincter

Levator ani Bulbourethral gland Deep transverse perineal muscle

Spongy urethra Corpus cavernosum Corpus spongiosum

Glans penis External urethral orifice

Bulb of penis Spermatic cord

Internal anal sphincter

Testicular artery Pampiniform venous plexus Epididymis Testis Scrotum

Medial view

FIGURE 3-6. Male midsagittal through pelvis. (From Moore KL, Dalley AF. Clinically Oriented Anatomy. 5th ed. Baltimore: Lippincott Williams & Wilkins; 2006:407.)

Additional Concept Structure of the Penis The root of the penis is located in the superficial pouch and consists of: two crura—each formed of corpora cavernosa, the single bulb—formed of an expanded proximal portion of the corpora spongiosa containing the proximal penile urethra and the muscles covering each—the ischiocavernosus invests the crura, whereas the bulbospongiosus invests the bulb. The body (or shaft) of the penis is the main, pendulous part. The body expands on the distal end

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of the penis to form the glans (or head) penis. The glans projects proximally over the corpora to form the corona. The skin of the penis extends over the glans forming the prepuce. The external urethral orifice opens near the distal tip of the glans. Penile Support The penis is supported by the suspensory ligament of the penis—an extension of deep fascia that fuses with the deep fascia of the penis. The fundiform ligament of the penis is an extension of the membranous layer of superficial fascia, which blends with the superficial fascia of the penis.

Clinical Significance Erection and Ejaculation During erection, parasympathetic fibers relax the smooth muscles in arteries supplying the corpora cavernosa, allowing blood to flow in, whereas the bulbospongiosus and ischiocavernosus impede venous return. During ejaculation, sympathetic fibers close the internal urethral sphincter, parasympathetic fibers cause contraction of the smooth muscle of the urethra and the pudendal nerve causes rhythmic contraction of the bulbospongiosus. Lymphatic Drainage The lymphatic drainage of the testes follow the testicular vessels to lumbar lymph nodes, whereas lymphatic drainage of the scrotum is to superficial inguinal lymph nodes.

PERINEUM Structure of the perineum Area Overall

Structure Significance Boundaries: • Diamond-shaped area • Anterior—pubic symphysis between thighs • Posterior—coccyx • Divided into urogenital • Posterolateral— and anal triangles by a line sacrotuberous ligaments drawn between the ischial • Anterolateral—ischiopubic tuberosities ramus (continued)

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Structure of the perineum (continued) Area Urogenital triangle Anal triangle

Ischioanal fossae

Pudendal canal

Superficial perineal pouch

Deep perineal pouch

Structure Significance Anterior half of the diamond- Contains the scrotum and the shaped perineal region root of the penis in males and the vulva in females Posterior half of the Contains the anal canal and diamond-shaped perineal anus and the ischioanal region fossae in both sexes • Wedge-shaped, fascial • The superiorly oriented spaces between the apex is located along the levator ani (medially), the tendinous arch of the obturator internus (laterally), levator ani and skin of the buttock • Fat-filled space traversed (inferiorly) by inferior rectal • Anterior recess of fossae neurovascular elements extend into deep perineal • Fat allows for expansion of pouch anal canal, anus and rectum during defecation • Passageway composed of Conveys pudendal nerve and obturator fascia along the internal pudendal vessels lateral wall of the ischioanal fossa • Begins at lesser sciatic notch and ends at the perineal membrane Space between the perineal Contains roots of penis or membrane and membranous clitoris, ischiocavernosus and layer of superficial fascia bulbospongiosus, superficial transverse perinei, greater vestibular glands (female), and deep perineal branches of internal pudendal vessels and pudendal nerve Space between the perineal Contains anterior recess of membrane and the inferior ischioanal fossa, deep fascia of the pelvic transverse perinei, external diaphragm urethral sphincter, and part of the urethra (and bulbourethral glands in the male)

The rectum and anal canal are presented with the large intestine in Chapter 2.

Additional Concept Pudendal Neurovascular Elements Before entering the pudendal canal, the pudendal nerve and internal pudendal vessels give off inferior rectal

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branches that course across the fossa to the rectum, anal canal, and anus. The pudendal nerve and internal pudendal vessels terminate by dividing into perineal (superficial pouch structures), dorsal artery and nerve of the penis or clitoris branches (deep pouch structures), and posterior scrotal or labial branches. Fascia of the perineum Fascia/Connective Tissue Membranous layer of superficial fascia (Colles’)

Perineal membrane

Perineal body

Significance/Structure • Along the posterior edge of the urogenital membrane, fuses with the perineal membrane and perineal body • Laterally, fuses with the fascia lata of the thigh; anteriorly, it is continuous with the membranous layer of superficial fascia of the abdomen (Scarpa’s) • Deep fascia spanning the urogenital triangle, investing the bulbospongiosus, ischiocavernosus, and transverse perinei muscles • Pierced by the urethra and the vagina in the female • Forms roof of superficial perineal pouch • Fibromuscular mass between the anus and perineal membrane • Serves as an attachment for bulbospongiosus, transverse perineal muscles, external anal sphincter, and levator ani

Additional Concept The fatty layer of superficial fascia in the perineum is continuous with the fatty layer over the abdomen and makes up the bulk of the two labia majora and mons pubis in females.

Clinical Significance Episiotomy Damage to the perineal body as may occur during childbirth, trauma, disease, or infection may lead to prolapse of the pelvic viscera. An episiotomy is performed during childbirth to enlarge the vaginal orifice and spare lasting damage to the perineal body.

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Muscles of the perineum Proximal Muscle Attachment BulboMale— spongiosus perineal body and median raphe; female— perineal body

Distal Attachment Innervation Male— Deep perineal perineal membrane, corpora spongiosum, and cavernosa and fascia of bulb of penis; female— fascia of bulbs of vestibule Ischiocav- Ischiopubic rami Crura of penis ernosus and ischial or clitoris tuberosities External Coccyx via Perineal body, Inferior rectal anal anococcygeal surrounds sphincter ligament and anus skin around anus External Ischiopubic rami Surrounds Deep urethral and ischial urethra; perineal sphincter tuberosities males— ascends to prostate, females— forms uterovaginal sphincter Deep Perineal body transverse perineal

Superficial Ischial transverse tuberosities perineal

Main Actions Male—assists in erection and ejaculation and emptying of urethra after micturition; female— assists in erection Maintains erection of penis or clitoris Closes anus, supports perineal body and pelvic floor Compresses urethra for the maintenance of urinary continence

Fixes perineal body to support pelvic viscera and resist intraabdominal pressure

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Back

4

INTRODUCTION The back consists of the vertebral column, spinal cord and nerves, and the muscles responsible for posture and movement of the vertebral column.

VERTEBRAL COLUMN Vertebral column structure The vertebral column is composed of intervertebral disks and 33 vertebrae: ■ ■ ■ ■ ■

7 cervical 12 thoracic 5 lumbar 5 fused sacral 4 fused coccygeal

The vertebral column protects the spinal cord and spinal nerves and supports the weight of the body. Curvatures of the vertebral column Curvature Cervical Lumbar

Thoracic Sacral

Description • Concave posteriorly (lordosis) • Secondary curvatures—cervical develops when infant begins to hold up head, lumbar develops when infant begins to walk • Concave anteriorly (kyphosis) • Primary curvatures—present at birth

Significance Provide resiliency to vertebral column

Additional Concept Axial and Appendicular Skeleton The axial skeleton is composed of the vertebral column, cranium, and thoracic cage (ribs, sternum, and hyoid bone). The appendicular skeleton is everything else (pectoral and pelvic girdles and the limbs).

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Normal

Kyphosis

Lordosis

Normal

Scoliosis

FIGURE 4-1. Curvatures of the vertebral column. (From Dudek RW, Louis TM. High-Yield Gross Anatomy. 3rd ed. Baltimore: Lippincott Williams & Wilkins; 2008:2.)

Clinical Significance Excess Curvature Excess thoracic kyphosis (humpback) is often caused by osteoporosis. Excess lumbar lordosis (sway back) is often seen in pregnancy. Scoliosis (crooked back) is a common lateral deformity of the vertebral column in pubertal girls. Structure of the vertebrae The vertebrae generally increase in size as progress inferiorly, a reflection of the increasing weight of the body. Vertebrae possess regional characteristics. Vertebrae Characteristic Significance • Most anterior; supports body weight, Typical Body progressively larger as move inferiorly down column • Covered on superior and inferior surface by hyaline cartilage • Peripheral border possesses epiphysial rim—a slight elevation that provide attachment for the annuli fibrosi of the intervertebral discs • Posterior to the body Vertebral arch • Formed by a pair of lamina and a pair of pedicles • With the posterior aspect of the body, forms the vertebral foramen—contains spinal cord (continued)

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Structure of the vertebrae (continued) Vertebrae Characteristic Significance Lamina • Pair of platelike processes that form the posterior part of vertebral arch • Meet posteriorly in the midline Pedicle • Pair of short processes that join vertebral arch to body • Form anterior part of vertebral arch • Notch on superior and inferior surfaces— vertebral notches: successive vertebral notches form intervertebral foramina, which permit passage of nerve roots and vessels Spinous • Midline posterior projection from junction process of laminae • Allows for muscle and ligament attachments Transverse • Project posterolaterally from vertebral processes (2) arch • Allow for muscle attachment and articulation with ribs (thoracic) Superior • Arise from junction of pedicles and laminae articular • Possess facet (zygapophysial) joints for processes (2) articulation with adjacent processes • Limit undo movement of vertebral column Inferior and maintain vertebral alignment articular processes (2) Identifying Regional Characteristics Body Superior surfaces possess uncinate process Cervical Spinous • Bifid process • C7, long—vertebra prominens Transverse Possess transverse foramina for passage of process vertebral vessels and sympathetic fibers Spinous Long, inferiorly directed Thoracic process Transverse Possess facets for articulation with head and process tubercle of ribs Massive for weight bearing Body Lumbar Short and stout Spinous process Fused Sacral • 5 sacral vertebrae fuse to form sacrum • Remnants of characteristics typical to vertebrae are still identifiable Coccygeal Fused Remnant of taillike caudal eminence

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Additional Concept Vertebral (Spinal) Canal Adjacent vertebral foramina form the vertebral canal— contain the spinal cord, meninges, nerve roots, vascular elements (internal venous plexus), and fat.

Clinical Concept Spina Bifida Failure of the vertebral arches to form correctly results in spina bifida; spina bifida occulta (a mild form) is often asymptomatic. More serious forms may result in herniation of meninges—meningocele or meninges and neural tissue through the deficiency. Vertebral Artery The long, tortuous course of the vertebral artery through the transverse cervical foramina may increase risk of insult because of stretch from rotation of the head, resulting in reduced blood flow to the brain, possibly causing dizziness and light-headedness.

Spinous process Dura mater Arachnoid Pia mater Superior articular facet

Internal vertebral venous plexus Lamina Spinal cord Posterior root of spinal nerve Root sheath Spinal ganglion

Vertebral artery Vertebral veins

Anterior root of spinal nerve Pedicle Vertebral body Nucleus pulposus

Anulus fibrosus

Posterior longitudinal ligament

Intervertebral cartilage (disk) Anterior longitudinal ligament

FIGURE 4-2. Typical vertebra, superior aspect. (Asset provided by Anatomical Chart Company.)

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Joints of the back (Figure 4-2) Joint Atlantooccipital

Type Synovial

Articulation C1 vertebra with occipital bone Atlantoaxial— Lateral— C1 with C2 2 lateral and synovial; vertebrae 1 median median— pivot

Intervertebral

Cartilaginous

Surfaces of adjacent vertebrae connected by intervertebral discs

Uncovertebral Synovial

Adjacent cervical vertebrae

Zygapophysial (facet)

Between superior and inferior articulating processes of adjacent vertebrae

Structure • Strengthened by anterior and posterior atlanto-occipital membranes • Strengthened and maintained by the cruciform ligament— formed by longitudinal bands and the transverse ligament of the atlas • Alar ligaments—prevent excessive rotation • The tectorial membrane— continuation of posterior longitudinal ligament, covers the alar and transverse ligaments • Intervertebral discs provide strong attachment between adjacent vertebral bodies— consist of outer fibrocartilaginous anulus fibrosis (attaches to epiphysial rim) and central compressible nucleus pulposus • Anterior and posterior longitudinal ligaments strengthen, provide stability, and limit extension and flexion of the vertebral column, respectively Uncinate process on superior surface of cervical vertebral bodies with inferior surface of vertebral body superior to it • Strengthened by accessory ligaments • Allow for gliding movements

Additional Concept Multiple accessory ligaments help to strengthen and support the joints of the vertebral column:

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ligamentum flavum—connects adjacent vertebral arches supraspinous—connects adjacent spinous processes interspinous—connects adjacent spinous processes ligamentum nuchae—connects external occipital protuberance and cervical spinous processes intertransverse ligaments—connects adjacent transverse processes

Clinical Significance Slipped Disc Herniation of the nucleus pulposus into or through the anulus fibrosis is a common cause of lower back pain and is often called a slipped or ruptured disk.

SPINAL CORD Structure of the spinal cord (Figure 4-2) The spinal cord is continuous superiorly with the medulla at the foramen magnum and ends inferiorly at the L1–L2 vertebral level. The spinal cord serves as a reflex center and conduction pathway, connecting the brain to the periphery. It is located within the vertebral canal and gives rise to 31 pairs of spinal nerves. Feature Cervical enlargement

Description Enlarged portion of spinal cord from C4–T1

Lumbar enlargement

Enlarged portion of spinal cord from L1–S3

Medullary cone

Tapering end of the spinal cord

Formed from anterior and posterior roots that arise from the lumbar enlargement and medullary cone Spinal nerves • 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, 1 (31 pairs) coccygeal Cauda equina

Significance Gives rise to the anterior rami that form the brachial plexus—innervates upper limbs Gives rise to the anterior rami that form the lumbosacral plexus—innervates lower limbs • Located at L1–L2 vertebral level • Nerve roots contribute to cauda equina Located in the lumbar cistern— continuation of subarachnoid space in the dural sac caudal to the medullary cone • Formed of anterior and posterior roots from the spinal cord segments (continued)

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Structure of the spinal cord (continued) Feature

Description Significance • Terminate by dividing into • Each contains somatic anterior and posterior primary afferent and efferent rami fibers and between T1–L2 contain presynaptic sympathetic fibers, between S2–S4 contain presynaptic parasympathetic fibers • Anterior roots contain fibers • Anterior—efferent Roots— of somatic and visceral motor anterior and • Posterior—afferent neurons • Join to form spinal nerves posterior • Posterior roots contain somatic and visceral afferent fibers Located along posterior root Contains primary afferent cell Spinal bodies of the somatic and ganglion visceral sensory systems Divided into posterior, lateral Located on the inside of Gray matter (visceral motor, between T1–L2), the spinal cord, deep to and anterior (somatic motor) horns the white matter • Divided into anterior, lateral, White matter Located on the outside of and posterior funiculi the spinal cord, superficial • Contains ascending (afferent) to the gray matter and descending (efferent) fiber tracts • Anterior—supply innervation Terminal branches of Rami— to majority of body, often anterior and spinal nerves form plexuses posterior • Posterior—supply segmental innervation to the back

Vessels of the spinal cord (Figure 4-2) Artery Anterior spinal

Origin Vertebral

Posterior spinal (2)

Either vertebral or posterior inferior cerebellar Ascending cervical, deep cervical, vertebral, posterior intercostal and lumbar

Segmental

Description Supplies anterior 2/3 of spinal cord superiorly Supplies posterior 1/3 of spinal cord superiorly • Enter vertebral canal through intervertebral foramina • Supply spinal cord and coverings segmentally • Anastomose with spinal arteries (continued)

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Vessels of the spinal cord (continued) Artery Radicular— anterior and posterior Medullary

Origin Segmental

Vein Anterior spinal (3) Posterior spinal (3) Medullary Radicular Internal vertebral venous plexus

Termination Drained by medullary and radicular veins

Description Supply nerve roots and associated meninges • Variable, but prevalent in the region of the cervical and lumbosacral enlargements • Supplement spinal arterial supply Description • Generally parallel arterial supply • Eventually drain into the internal vertebral venous plexus

Drain into internal vertebral venous plexus Drain into dural sinuses of cranial vault

• Communicates with external venous plexus on external aspect of vertebrae • Potential route for infection spread from cranial vault

Structure of spinal cord meninges (Figure 4-2) The spinal cord meninges support and protect the nerve roots and form the subarachnoid space. From superficial to deep: ■ ■ ■

dura mater arachnoid mater pia mater

Structure Dura mater

Epidural space Dural root sheaths

Description • Outer layer of meninges • Continuous with meningeal layer of cranial dura superiorly Between vertebrae and dura mater Extensions of the dural sac that cover spinal nerve roots and spinal nerves

Significance • Tough, fibrous layer • Separated from vertebrae by epidural space Contains fat and the internal vertebral venous plexus • Sheaths end by blending with the epineurium of the spinal nerves • Extend through intervertebral foramina (continued)

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Structure of spinal cord meninges (continued) Structure Dural sac

Subdural space

Arachnoid mater

Subarachnoid space

Arachnoid trabeculae Lumbar cistern

Description Long tubular sac that contains the spinal cord and cerebrospinal fluid • Potential space, between the dura and arachnoid mater • Filled with a loosely adhered cell layer • Middle meningeal layer • Encloses the subarachnoid space Between arachnoid mater and pia mater

Connective tissue strands that connect the arachnoid and pia mater Inferior prolongation of the subarachnoid space

• Delicate inner (deep) meninge in contact with the spinal cord • Deep to the subarachnoid space • 21 pairs Denticulate • Lateral extensions of pia ligaments mater between the anterior and posterior roots Filum terminale— • Inferior extension of pia mater internus and • Extends from medullary externus cone to inferior aspect of dural sac (interna) and to the tip of the coccyx (externa) Pia mater

Significance Begins at the foramen magnum, anchored to coccyx by filum terminale Site of subdural hematoma when trauma causes bleeding into space

Lines dural sac and dural root sheaths • Contains cerebrospinal fluid, arachnoid trabeculae, and blood vessels • Inferior prolongation forms the lumbar cistern Span the subarachnoid space Contains the cauda equina and filum terminale internus Invests spinal blood vessels and the roots of the spinal nerves

Anchors spinal cord to the dura mater

Anchors inferior end of spinal cord to dura mater and coccyx

Clinical Significance Anesthesia Epidural anesthesia entails injection of a local anesthetic around the sacral spinal nerves, external to the dural sac.

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Spinal Tap and Block A lumbar puncture (spinal tap) is performed for extraction of cerebrospinal fluid from the lumbar cistern for examination. A spinal block entails introduction of an anesthetic into the cerebrospinal fluid through a lumbar puncture.

MUSCULATURE Muscles of the back The muscles located on the back are divided into extrinsic and intrinsic. The extrinsic muscles of the back are discussed with the upper limb (superficial layer) and thorax (intermediate layer), with which they are associated functionally. Intrinsic Back Proximal Distal Main Muscle Attachment Attachment Innervation Actions Superficial Layer • Capitis— mastoid process and superior nuchal line • Cervicis— transverse processes of C1–C4 vertebrae Intermediate Layer (Erector Spinae)

Segmental innervation by posterior rami of spinal nerves

• Laterally flex neck and rotate head • Extend head and neck when contracting bilaterally

Angles of lower ribs and transverse processes of thoracic and cervical vertebrae

Segmental innervation by posterior rami of spinal nerves

Laterally flex vertebral column; extend vertebral column (chief extensor of column) and head, control flexion by gradual relaxation of fibers when acting bilaterally

Splenius— capitis and cervicis

Nuchal ligament and C7–T4 vertebrae

Arise as fused muscle mass from iliac crest and sacrum, sacroiliac ligaments, and spinous Longissimus— processes thoracis, of sacral cervicis and and lumbar capitis vertebrae Iliocostalis— lumborum, thoracis, and cervicis

Angles of ribs and transverse processes of thoracic and

(continued)

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Muscles of the back (continued) Intrinsic Back Muscle

Proximal Distal Main Attachment Attachment Innervation Actions cervical vertebrae and mastoid process Spinous Spinalis— processes of thoracis, upper cervicis, thoracic and capitis vertebrae and cranium Deep Layer (Transversospinal Group) Segmental Spinous • Extends Semispinalis— Transverse innervation processes thoracic and thoracis, processes by posterior of 4–6 cervical cervicis and C4–T12 rami of vertebrae regions of capitis superior and spinal vertebral nerves occipital column and bone head • Rotates vertebral column Posterior Spinous Stabilizes Multifidus sacrum, processes vertebrae posterior of 2–4 iliac spine, vertebrae transverse superior processes T1–T3 and articular processes of C4–C7 Transverse Junction of Rotators— processes lamina and brevis and transverse longus process or spinous processes of 1 (brevis), 2 (longus) vertebrae superior Extension and Spinous Spinous Interspinales rotation of processes processes of (continued)

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Muscles of the back (continued) Intrinsic Back Muscle

Intertransversarii

Levator costarum

Proximal Attachment of cervical and lumbar vertebrae Transverse processes of cervical and lumbar vertebrae

Distal Main Attachment Innervation Actions vertebral vertebrae column immediately superior Lateral Transverse flexion and processes of stabilization of adjacent vertebral vertebrae column

Transverse processes of C7–T11 vertebrae

Adjacent rib between tubercle and angle

Elevate ribs, assist in lateral flexion of vertebral column

Additional Concept The muscles of the back may be divided into 3 layers: superficial—associated with the upper limb; intermediate—associated with the thorax; and deep—associated with movement of the vertebral column. They are also known as the intrinsic muscles of the back or true back muscles. Mnemonic Erector Spinae Muscles From lateral to medial: I Like Spaghetti Iliocostalis Longissimus Spinalis Suboccipital triangle The suboccipital triangle is a muscular triangle inferior to the occipital region of the head; it contains the vertebral artery, posterior arch of the atlas, and the suboccipital nerve (C1). Suboccipital Region Borders

Structure • Roof—semispinalis capitis • Floor—atlanto-occipital membrane and arch of C1

Significance • Identifiable muscular triangle in the (continued)

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Suboccipital triangle (continued) Suboccipital Region

Muscles Rectus capitis posterior major

Structure • Superomedial—rectus capitis posterior major • Superolateral—superior oblique • Inferolateral—inferior oblique

• Proximal attachment: C2 spinous process • Distal attachment: inferior nuchal line of occipital bone Rectus capitis posterior • Proximal attachment: C1 posterior arch minor • Distal attachment: inferior nuchal line of occipital bone Inferior oblique of the • Proximal attachment: C2 spinous process head • Distal attachment: C1 transverse process Superior oblique of the • Proximal attachment: C1 transverse process head • Distal attachment: occipital bone

Significance suboccipital region

• Actions: extend and rotate head • Innervation: suboccipital nerve (C1)

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Lower Limb

The pelvic (anterior) aspect of the bones of the gluteal region are described in Chapters 3 and 4.

INTRODUCTION The lower limb is divided for descriptive purposes by skeletal elements into: ■ ■ ■ ■

gluteal region—portion between thigh and trunk posteriorly that includes the pelvic girdle: ilium, ischium, and pubis thigh—portion between the gluteal region posteriorly and the knee that includes the femur leg—portion between the knee and ankle that includes the tibia and fibula foot—portion distal to the ankle that includes the metatarsals and phalanges; the tarsal bones form the ankle

GLUTEAL REGION Bones of the gluteal region (Figure 5-1) Bone Sacrum

Significance Fused spinal processes of sacral vertebrae Transmit posterior rami of first 4 sacral nerves Inferior opening of the vertebral canal between the sacral cornu (horns) Coccyx Apex of the coccyx • Directed inferiorly • Coccyx is formed by the fusion of the 4 inferiormost vertebrae Hip Bone (Pelvic Bone, Coxal Bone)—Fusion of the 3 Bones Below Ilium Body of ilium Contributes to the acetabulum Wing (ala) of ilium • Concave surface • Marked by the anterior, posterior, and inferior gluteal lines (continued)

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Feature Median crest Posterior sacral foramina Sacral hiatus

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Bones of the gluteal region (continued) Bone

Characteristic Iliac crest

Posterior superior iliac spine Posterior inferior iliac spine Anterior gluteal line

Ischium

Pubis

Significance • Bony ridge between the anterior superior, and posterior superior iliac spines • Attachment for fascia lata, tensor of fascia lata, external oblique, internal oblique, transverse abdominal, latissimus dorsi, quadratus lumborum, erector spinae, and iliacus Attachment for sacroiliac ligaments and multifidus Part of auricular surface of ilium

• Gluteus medius attaches between anterior and posterior gluteal lines • Gluteus minimus attaches between anterior and inferior gluteal lines Posterior gluteal • Gluteus maximus attaches posterior to the line posterior gluteal line • Gluteus medius attaches between anterior and posterior gluteal lines Inferior gluteal line Gluteus minimus attaches between anterior and inferior gluteal lines Greater sciatic • Notch converted into greater sciatic foranotch/foramen men by the sacrospinous ligament • Major passageway for structures exiting the pelvis and entering the gluteal region— including: piriformis, superior and inferior gluteal vessels and nerves, sciatic and posterior femoral cutaneous nerves, internal pudendal vessels, pudendal nerve and nerves to obturator internus, and quadratus femoris Ischial spine Attachment for superior gemellus and sacrospinous ligament Ischial tuberosity Attachment for hamstring portion of adductor magnus, hamstrings, and sacrotuberous ligament Body Contributes to the acetabulum Lesser sciatic • Notch converted into lesser sciatic foramen notch/foramen by the sacrospinous and sacrotuberous ligaments • Passageway for structures exiting and entering the perineum—tendon of obturator internus (exiting), internal pudendal vessels, and pudendal nerve (entering) Body Contributes to the acetabulum

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Ilium S1 Sacrum Anterior superior iliac spine Anterior inferior iliac spine Pubis Greater trochanter Neck of femur

Pubic symphysis Ischium

Head of femur

Lesser trochanter Tibial collateral ligament

Quadriceps femoris tendon

Medial epicondyle

Femur Medial femoral condyle Patella Lateral epicondyle

Fibular collateral ligament Patellar ligament

Medial tibial condyle

Lateral femoral condyle Tibial condyle Head of fibula

Tibial tuberosity Interosseous membrane

Talus Medial cuneiform

Tibia Fibula

Medial malleolus

Lateral malleolus

FIGURE 5-1. Lower limb bones. Anterior view. (Asset provided by Anatomical Chart Company.)

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Additional Concept Acetabulum The acetabulum is formed by the bodies of the pubis, ischium, and ilium; it forms the socket of the hip joint.

Clinical Significance Contusion of the iliac crest is known as a “hip pointer.” Muscles of the gluteal region Proximal Attachment Ilium posterior to posterior gluteal line, sacrum, coccyx; and sacrotuberous ligament Gluteus Ilium between medius anterior and posterior gluteal lines Gluteus Ilium between minimus anterior and inferior gluteal lines Tensor of Anterior superior fascia lata iliac spine Muscle Gluteus maximus

Piriformis

Obturator internus

Sacrum and sacrotuberous ligament Margins of obturator foramen and obturator membrane Ischial spine

Superior gemellus Inferior Ischial gemellus tuberosity Quadratus femoris

Distal Attachment Innervation Iliotibial tract Inferior and gluteal gluteal tuberosity

Greater trochanter of femur

Lateral condyle of tibia via iliotibial tract Greater trochanter of femur

Intertrochanteric crest

Superior gluteal

Main Actions • Extends and laterally rotates thigh • Steadies thigh • Abducts and medially rotates thigh • Levels pelvis when contralateral leg is unsupported

Sacral plexus • Laterally (S1 and S2) rotates thigh • Assist in holding head Nerve to of femur in obturator acetabulum internus

Nerve to quadratus femoris

Clinical Significance The gluteal region is a common site for intramuscular injection; injections are made in the superolateral quadrant to avoid neurovascular elements.

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Mnemonic Lateral Rotators of the Hip Joint Play Golf Or Go On Quaaludes Piriformis Gemellus superior Obturator internus Gemellus inferior Obturator externus Quadratus femoris Nerves of the gluteal region Nerve Superior gluteal

Origin Sacral plexus

Inferior gluteal Pudendal Sciatic Nerve to quadratus femoris Nerve to obturator internus Posterior femoral cutaneous Superior clunial Middle clunial Inferior clunial Iliohypogastric

Structures Innervated Gluteus medius, gluteus minimus, tensor of fascia lata Gluteus maximus Supplies the perineum; supplies no structures in the gluteal region Supplies the lower limb; supplies no structures in the gluteal region Quadratus femoris and inferior gemellus Obturator internus and superior gemellus Skin of gluteal region

L1–L3 S1–S3 S2–S3 Lumbar plexus Skin of buttock

Vessels of the gluteal region (Figure 5-2) Artery Superior gluteal Inferior gluteal

Internal pudendal

Origin Internal iliac

Description Supplies gluteus maximus, gluteus medius, gluteus minimus, and tensor of fascia lata • Supplies gluteus maximus, obturator internus, and quadratus femoris • Participates in cruciate anastomosis with the deep femoral (1st perforating branch) and the medial and lateral circumflex arteries • Supplies structures in the perineal region • Supplies no structures in the gluteal region

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External iliac artery Inferior epigastric artery Superficial epigastric artery Deep circumflex iliac artery Superficial circumflex iliac artery Deep femoral artery Lateral circumflex femoral artery: Ascending branch Transverse branch Descending branch

Aorta

Common iliac artery Internal iliac artery (cut) Superficial external pudendal artery Obturator artery Anterior and posterior branch of obturator artery Medial circumflex femoral artery

Perforating arteries Femoral artery

Descending genicular artery Superior lateral genicular artery Inferior lateral genicular artery Anterior tibial recurrent artery

Anterior tibial artery

Perforating branch of fibular artery Anterior lateral malleolar artery Lateral tarsal artery

Arcuate artery Dorsal digital arteries

Superior medial genicular artery Inferior medial genicular artery Posterior tibial artery Interosseous membrane

Anterior medial malleolar artery Dorsalis pedis artery Medial tarsal arteries Deep plantar artery Dorsal metatarsal arteries

FIGURE 5-2. Arteries of lower limb, anterior view. (From Tank PW, Gest TR. LWW Atlas of Anatomy. Baltimore: Lippincott Williams & Wilkins; 2009:148.)

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Additional Concept Venous Drainage The venous drainage generally parallels arterial supply.

THIGH REGION Bones of the thigh (Figures 5-1 and 5-2) Bone Femur (thigh bone)

Feature Head

Neck Greater trochanter

Lesser trochanter Trochanteric fossa Intertrochanteric line Intertrochanteric crest Linea aspera

Gluteal tuberosity Adductor tubercle

Significance • Articulates with acetabulum • Bears a fovea for attachment of the ligament of the head of the femur Attachment for the capsule of the hip joint Attachment for gluteus medius and minimus, piriformis, obturator internus, superior and inferior gemelli, and vastus lateralis Attachment for iliacus and psoas major Attachment for obturator externus Attachment for iliofemoral ligament and vastus medialis Attachment for quadratus femoris Attachment for pectineus, iliacus, vastus medialis and lateralis, adductor magnus, longus and brevis, biceps femoris (short head), and gluteus maximus Attachment for gluteus maximus • Associated with the medial epicondyle • Attachment for adductor magnus Attachment for vastus intermedius Articulate with tibial plateau

Shaft Medial condyle Lateral condyle Intercondylar fossa • Depression between medial and lateral condyles • Attachment for anterior and posterior cruciate ligaments Medial epicondyle • Attachment for tibial collateral ligament, gastrocnemius • Bears adductor tubercle Lateral epicondyle Attachment for fibular collateral ligament, gastrocnemius, plantaris, and popliteus

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Clinical Significance Coxa Vara and Coxa Valga When the angle of inclination between the neck and shaft of the femur is decreased, the condition is coxa vara; when it is increased, it is coxa valga. Femoral Fracture Femoral fractures often occur at the neck; spiral fractures occur in the shaft of the femur. Muscles of the thigh Proximal Distal Muscle Attachment Attachment Innervation Main Actions Anterior Compartment—Hip Flexors and Knee Extensors Pectineus Pubis Pectineal line Femoral or Adducts, flexes, of femur obturator and medially rotates thigh Psoas major

T12 and lumbar Lesser troch- Segmental vertebrae anter of femur (L1–L3)

Flexes thigh and stabilizes hip joint

Psoas minor

T12–L1

Pectineal line Segmental

Iliacus

Iliac fossa

Lesser troch- Femoral anter of femur

Sartorius

Anterior superior iliac spine

Medial condyle of tibia via pes anserinus

Rectus femoris

Anterior inferior Tibial tuberoiliac spine sity via patellar ligament

Extends leg, flexes thigh, and stabilizes hip joint

Vastus lateralis

Greater trochanter and linea aspera of femur

Extends leg

Vastus medialis

Intertrochanteric line and linea aspera of femur

Flexes, abducts and laterally rotates thigh, flexes leg

Vastus Femoral shaft intermedius (continued)

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Muscles of the thigh (continued) Proximal Distal Muscle Attachment Attachment Innervation Medial Compartment—Thigh Adductors Adductor Pubis Linea aspera Obturator longus of femur

Main Actions Adducts thigh

Adductor brevis Adductor magnus

• Adductor • Adductor • Adductor portion: pubis portion: glu- portion: • Hamstring teal tubero- obturator portion: ischial sity and • Hamstring tuberosity linea aspera portion: • Hamstring tibial diviportion: sion of adductor sciatic tubercle of femur

• Adductor portion: adducts thigh • Hamstring portion: extends thigh

Gracilis

Pubis

Adducts thigh, flexes and medially rotates leg

Medial condyle of tibia via pes anserinus

Obturator

Obturator externus

Margins of obtu- Trochanteric • Laterally rator foramen fossa of rotates thigh and obturator femur • Holds head of membrane— femur in externally acetabulum Posterior Compartment—Knee Flexors and Hip Extensors Semitendinosus

Semimembranosus Biceps femoris

Ischial tuberosity

Medial condyle of tibia via pes anserinus

Tibial division Extend thigh, of sciatic flex and medially rotate leg

Medial condyle of tibia • Long head: Head of fibula • Long head: Flexes and ischial tuberotibial divi- laterally rotates sity sion of leg, flexes thigh • Short head: sciatic linea aspera • Short head: common fibular division of sciatic

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Additional Concept Quadriceps Femoris The rectus femoris, vastus lateralis, vastus medialis, and vastus intermedius are collectively referred to as the quadriceps femoris. Hamstrings The semitendinosus, semimembranosus, and biceps femoris are collectively referred to as the hamstrings.

Clinical Significance Cramp A cramp or spasm in the anterior thigh muscles—a “Charley Horse”—usually involves the rectus femoris. Gracilis Gracilis is sometimes transplanted to replace damaged muscles elsewhere in the body. Groin pull A groin pull usually refers to straining the proximal aspect of the musculature of the medial compartment of the thigh. Mnemonics Adductor Magnus AM SO: Adductor Magnus innervated by Sciatic and Obturator. Pes Anserinus Pes Anserinus—Say Grace before Serving Tea Sartorius Gracilis Semitendinosus Nerves of the thigh Nerve Femoral

Obturator

Origin Structures Innervated Lumbar plexus • Pectineus, sartorius, iliacus, rectus femoris, vastus lateralis, medialis, and intermedius • Sensory to skin over anteromedial thigh Adductor longus, adductor brevis, gracilis, pectineus, obturator externus, and adductor magnus (continued)

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Nerves of the thigh (continued) Nerve

Origin

Structures Innervated

Tibial division of sciatic

Sciatic

Long head of biceps femoris, semitendinosus, semimembranosus

Common fibular division of sciatic Genitofemoral

Short head of biceps femoris Lumbar plexus Sensory to skin of inguinal region

Lateral femoral cutaneous Posterior femoral cutaneous

Sensory to skin over lateral thigh Sacral plexus

Sensory to skin of gluteal region and posterior thigh

Vessels of the thigh (Figure 5-2) Artery

Origin

Description

Internal pudendal

Internal iliac

Supplies external genitals and perineal region

Obturator

• Divides into anterior and posterior branches • The posterior branch gives rise to the acetabular branch and the artery to the head of the femur • Both branches supply the adductor compartment of the thigh

Femoral

Continuation of external iliac

• Gives rise to deep femoral, superficial epigastric, superficial circumflex iliac, external pudendal, medial and lateral femoral circumflex, and descending genicular • Terminates by becoming the popliteal artery after passing through the adductor hiatus

Deep femoral

Femoral

• Gives rise to 4 perforating branches that supply adductor magnus and hamstrings • 1st perforating branch participates in cruciate anastomosis with the inferior gluteal and the medial and lateral circumflex arteries

Superficial epigastric

Supplies subcutaneous tissues—lymph nodes, skin, and fascia over the abdominal wall

Superficial circumflex iliac

Supplies subcutaneous tissues—lymph nodes, skin, and fascia over the inguinal region (continued)

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Vessels of the thigh (continued) Artery

Origin

Superficial external pudendal Deep external pudendal Medial femoral circumflex

Description Supplies subcutaneous tissues—skin and fascia over the external genitals

Deep femoral

• Supplies most of the blood to the head and neck of femur • Participates in cruciate anastomosis with the inferior gluteal, lateral circumflex, and 1st perforating branch of the deep femoral

Lateral femoral circumflex

• Supplies neck of femur and contributes to anastomosis around knee joint • Participates in cruciate anastomosis with the inferior gluteal, medial circumflex, and 1st perforating branch of the deep femoral

Descending Femoral genicular

Supplies subcutaneous tissue on medial aspect of knee and contributes to anastomosis around knee

Additional Concept Venous Drainage Venous drainage generally follows arterial supply.

Clinical Significance Femoral Artery The proximal portion of the femoral artery is easily accessible and easily damaged because of its superficial location.

LEG REGION Leg bones (Figures 5-1, 5-4, and 5-5) Bone Tibia

Feature Medial condyle

Significance • Articulates with femoral condyles • Attachment for semimembranosus and tibial collateral ligament (continued)

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Leg bones (continued) Bone

Fibula

Feature

Significance

Lateral condyle

• Articulates with femoral condyles • Attachment for iliotibial band

Anterior intercondylar area Posterior intercondylar area

• Located between the condyles • Provide attachment sites for anterior and posterior cruciate ligaments and the menisci

Tuberosity of the tibia

Attachment for patellar ligament

Shaft

Attachment for tibial collateral ligament, popliteus, soleus, flexor digitorum longus, interosseous membrane, gracilis, and semitendinosus

Soleal line

Attachment for popliteus, soleus, flexor digitorum longus, and tibialis posterior

Medial malleolus

• Attachment for deltoid ligament • Lateral surface articulates with the talus

Head

Attachment for biceps femoris, fibular collateral ligament, fibularis longus, extensor digitorum longus, and soleus

Neck

Common fibular nerve wraps around neck to access the anterior aspect of the leg

Shaft

Attachment for interosseous membrane, extensor digitorum longus, extensor hallucis longus, soleus, tibialis posterior, fibularis longus, brevis, and tertius

Lateral malleolus

• Medial surface articulates with the talus • Attachment for the posterior and anterior talofibular ligaments and the calcaneofibular ligament

Clinical Significance Fractures Tibia The most common site for a fracture of the tibia is along the shaft at the junction of its middle and inferior thirds; it is the narrowest part and has a relatively poor blood supply.

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Fibula Fracture of the fibula often occurs proximal to the lateral malleolus and is often associated with fracture dislocations of the ankle joint. Muscles of the leg Proximal Muscle Attachment Anterior Compartment

Distal Attachment

Tibialis anterior

1st metatarsal Deep fibular

Dorsiflexes ankle, inverts foot

Middle and distal phalanges digits 2–5

Extends digits 2–5, dorsiflexes ankle

Tibia and interosseous membrane

Extensor digitorum longus Extensor hallucis longus

Innervation

Fibula and inter- Distal osseous mem- phalanx brane digit 1

Fibularis tertius

Main Actions

Extends digit 1, dorsiflexes ankle

5th metatarsal

Dorsiflexes ankle, everts foot

Fibularis Fibula longus Fibularis brevis Posterior Compartment

1st metatarsal Superficial fibular Tuberosity of 5th metatarsal

Plantarflex ankle, evert foot

Gastrocnemius

Femoral condyles

Calcaneus via Tibial calcaneal tendon

Flexes leg, plantarflexes ankle

Soleus

Soleal line of tibia and fibula

Plantarflexes ankle

Plantaris

Oblique popliteal ligament and lateral supracondylar ridge of femur

Plantarflexes ankle and provides proprioceptive information on tension of triceps surae

Popliteus

Lateral femoral Tibia condyle and lateral meniscus

Flexes and unlocks knee

Lateral Compartment

(continued)

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Muscles of the leg (continued) Muscle Tibialis posterior

Proximal Attachment Fibula and interosseous membrane

Flexor hallucis longus

Flexor digitorum longus

Distal Attachment Tuberosity of navicular Distal phalanx digit 1

Tibia and fibula

Distal phalanges digits 2–5

Innervation

Main Actions Plantarflexes ankle, inverts foot Flexes joints of 1st digit, plantarflexes ankle, and supports longitudinal arches of foot Plantarflexes ankle, flexes digits 2–5, and supports longitudinal arches of foot

Additional Concept Triceps Surae The gastrocnemius, soleus, and plantaris are collectively referred to as the triceps surae.

Clinical Significance Compartment Syndrome Compartment syndrome is increased intracompartment pressure due to muscle swelling or shin splints. Shin splints is pain resulting from repetitive microtrauma to the tibialis anterior. Gastrocnemius Gastrocnemius strain is a painful injury resulting from tearing the medial belly of the muscle during knee extension and dorsiflexion of the ankle. Mnemonics Eversion versus Inversion The second letter in the name of the muscle indicates the function: Eversion: perineus longus perineus brevis

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perineus tertius Inversion: tibialis anterior tibialis posterior Plantarflexion Plantarflexion occurs when you step on a plant with the sole of your foot. Nerves of the leg Nerve Tibial

Origin Sciatic

Common fibular Superficial fibular

Common fibular

Deep fibular

Posterior femoral cutaneous Saphenous Lateral sural cutaneous Medial sural cutaneous Superficial fibular Sural

Sacral plexus

Structures Innervated Supplies gastrocnemius, soleus, plantaris, popliteus, flexor hallucis longus, flexor digitorum longus, and tibialis posterior Gives rise to the lateral sural cutaneous and superficial and deep fibular Supplies fibularis longus and brevis and sensory to anterior aspect of distal leg Supplies tibialis anterior, extensor hallucis longus, extensor digitorum longus, and fibularis tertius Sensory to skin of calf

Femoral

• Sensory to medial aspect of leg • Runs with great saphenous vein Common fibular Sensory to posterolateral aspect of leg Tibial

Sensory to posterior aspect of leg

Common fibular Sensory to anterolateral aspect of leg Common fibular Sensory to lateral and posterior aspect and tibial of leg

Vessels of the leg (Figure 5-2) Artery Popliteal

Origin Femoral

Genicular

Popliteal

Description • Begins at the adductor hiatus as a continuation of the femoral • Gives rise to genicular, anterior, and posterior tibial arteries • Composed of superior lateral and medial, inferior lateral, and medial genicular • Contribute the anastomosis around the knee joint (continued)

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Vessels of the leg (continued) Artery Anterior tibial

Origin

Posterior tibial

Fibular

Posterior tibial

Supplies/Gives Rise to • Runs with deep fibular nerve on interosseous membrane • Supplies anterior leg and dorsum of foot, terminates as the dorsalis pedis • Gives off fibular artery • Supplies posterior aspect of leg and sole of foot, terminates as medial and lateral plantar arteries Supplies posterolateral aspects of leg

Additional Concept Venous Drainage Venous drainage generally parallels arterial supply.

Clinical Significance Posterior Tibial Artery The posterior tibial arterial pulse can be palpated between the medial malleolus and the calcaneal tendon.

FOOT REGION Bones of the foot (Figures 5-1 and 5-4) Bone Talus

Characteristic Trochlea Head

Calcaneus

Calcaneal tuberosity

Fibular trochlea

Significance Articulates with tibia and malleoli of tibia and fibula Articulates with the navicular, forming a ball-and-socket type joint, supported inferiorly by the plantar calcaneonavicular ligament Attachment for abductor digiti minimi, abductor hallucis, flexor digitorum brevis, plantar aponeurosis, long plantar ligament, quadratus plantae, and the plantar calcaneocuboid ligament Separates grooves for the tendons of fibularis longus and brevis (continued)

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Bones of the foot (continued) Bone

Characteristic Talar shelf

Navicular Tuberosity Cuboid Medial Articular surfaces cuneiform Intermediate cuneiform Lateral cuneiform Metatar- Base sals (5) Proximal Heads phalanges (5) Middle phalanges (5) Distal Tuberosity phalanges (4)

Significance Attachment for tibialis posterior, deltoid ligament, and plantar calcaneonavicular ligament; inferior surface grooved for tendon of flexor hallucis longus Attachment for tibialis posterior Bears facet for sesamoid bone in tendon of fibularis longus to glide Articulates with 4 bones—navicular, intermediate cuneiform, and 1st and 2nd metatarsals Articulates with 4 bones—navicular, medial and lateral cuneiforms, and 2nd metatarsal Articulates with 6 bones—navicular, intermediate cuneiform, cuboid, and 2nd, 3rd, 4th metatarsals Articulate with tarsal bones and adjacent metatarsals Articulate with proximal phalanges

Articulate with more distal phalanges

Ungual tuberosity supports the toenail

Clinical Significance Avulsion Sudden inversion of the foot may cause avulsion of the tuberosity of the 5th metatarsal,, the attachment for fibularis brevis. Muscles of the foot Muscle Dorsum Extensor digitorum brevis

Proximal Attachment

Distal Attachment

Calcaneus

Tendons of ex- Deep fibular tensor digitorum longus

Innervation

Main Actions Extend digits 2–5 (continued)

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Muscles of the foot (continued) Proximal Distal Muscle Attachment Attachment Innervation Extensor Proximal hallucis phalanx of brevis digit 1 Plantar Surface—Layer 1 (Most Superficial) Abductor Calcaneus Proximal pha- Medial hallucis lanx of digit 1 plantar Flexor Middle phadigitorum langes of brevis digits 2–5 Abductor Proximal pha- Lateral plantar digiti lanx of digit 5 minimi Plantar Surface—Layer 2 Quadratus Calcaneus Tendons of Lateral plantar plantae flexor digitorum longus Lumbricals Tendons of Extensor • 1st: medial flexor digitorum expansions plantar longus • 2nd–4th: lateral plantar Plantar Surface—Layer 3 Flexor Cuboid and 3rd Proximal Medial hallucis cuneiform phalanx of plantar brevis digit 1 Adductor • Oblique head: Lateral plantar hallucis metatarsals 2–4 • Traverse head: metatarsophalangeal joints Flexor digiti 5th metatarsal Proximal phaminimi lanx of digit 5 brevis Plantar Surface—Layer 4 Plantar in- Metatarsals 3–5 Proximal pha- Lateral plantar terossei (3) langes 3–5

Dorsal in- Metatarsals 1–5 Proximal phaterossei (4) langes 2–4

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Main Actions Extend digit 1

Abducts digit 1 Flexes middle phalanges of digits 2–5 Abducts digit 5

Assists with toe flexion Flex metatarsophalangeal joints, extend interphalangeal joints Flexes digit 1

• Adducts digit 1 • Maintains transverse arch of foot Flexes digit 5

• Adducts digits 2–4 • Flex metatarsophalangeal joints • Abducts digits 2–4 • Flex metatarsophalangeal joints

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Clinical Significance Extensor Digitorum Brevis A hematoma resulting from trauma to the extensor digitorum brevis produces edema near the ankle that is often confused with an ankle sprain. Nerves of the foot Nerve Saphenous

Origin Femoral

Medial sural cutaneous Superficial fibular Deep fibular

Calcaneal(s) Medial plantar

Lateral plantar

Sural

Structures Innervated • Runs with great saphenous vein • Sensory to medial aspect of foot Tibial Sensory to lateral aspect of ankle and foot Common fibular Sensory to dorsum of foot • Supplies extensor digitorum brevis • Sensory to skin between the 1st and 2nd toes Tibial and sural Sensory to heel Tibial • Supplies abductor hallucis, flexor digitorum brevis, flexor hallucis brevis and 1st lumbrical • Sensory to medial aspect of sole and medial 31⁄2 toes • Supplies quadratus planate, abductor digiti minimi, flexor digiti minimi brevis, plantar and dorsal interossei, lateral 3 lumbricals, and adductor hallucis • Sensory to lateral aspect of sole and lateral 11⁄2 toes Tibial and Sensory to lateral aspect of foot common fibular

Vessels of the foot (Figure 5-2) Artery Origin Dorsal Surface Dorsalis Anterior pedis tibial

Lateral tarsal Arcuate

Dorsalis pedis

Description • Continuation of the anterior tibial after it passes into the foot • Gives rise to the lateral tarsal, arcuate, 1st dorsal metatarsal, and deep plantar Anastomosis with arcuate Gives the 2nd, 3rd, and 4th dorsal metatarsals (continued)

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Vessels of the foot (continued) Artery Origin Dorsal Arcuate metatarsals Dorsal Dorsal digitals metatarsals 1st dorsal Dorsalis metatarsal pedis Deep plantar Plantar Surface Medial Posterior plantar tibial Lateral plantar Plantar Plantar metatarsals arch Plantar Plantar digitals metatarsals Plantar arch Lateral plantar

Description Give off 2 dorsal digitals Supplies the digits Supplies the 1st digit Anastomosis with lateral plantar to form plantar arch Divides into superficial and deep branches that supply the digits Forms plantar arch with deep plantar Give rise to plantar digitals Supply the digits Gives rise to plantar metatarsals

Additional Concept Venous Drainage Venous drainage generally parallels arterial supply.

MISCELLANEOUS Areas of lower limb (Figure 5-3) Feature Femoral triangle

Structure Triangular region in anterosuperior aspect of thigh, deep to fascia lata: • Superior border (base): inguinal ligament • Medial border: adductor longus • Lateral border: sartorius • Roof: fascia lata—deficiency: cribriform fascia and saphenous opening, pierced by great saphenous vein • Floor: iliopsoas (laterally) and pectineus (medially)

Significance Location of neurovascular structures entering and leaving thigh through subinguinal space, from lateral to medial: • Femoral nerve • Femoral sheath—contains: • Femoral artery • Femoral vein • Femoral canal (fat and deep inguinal lymph nodes)

(continued)

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Areas of lower limb (continued) Feature

Structure

Significance

Adductor • Intermuscular passage found canal deep to sartorius • Proximal opening—apex of femoral triangle, distal opening—adductor hiatus

• Also known as subsartorial canal • Transmits femoral artery, femoral vein, and saphenous nerve

Popliteal Fat-filled, diamond-shaped space fossa posterior to knee joint; boundaries: • Superolateral: biceps femoris • Superomedial: semimembranosus • Inferolateral: gastrocnemius • Inferomedial: gastrocnemius • Roof: popliteal fascia • Floor: popliteus

Contains: • Popliteal artery • Popliteal vein—receives small saphenous vein in fossa • Tibial nerve • Common fibular nerve • Popliteal lymph nodes

Arches of 3 arches formed by bones, the foot muscles, tendons, ligaments, and fascia 1. Medial longitudinal arch 2. Lateral longitudinal arch 3. Transverse arch

• Act as shock absorbers and springboards during locomotion and bear weight of body • Maintained by passive and dynamic support: • Passive—bones, connective tissue structures (plantar aponeurosis and long, short and spring ligaments) • Dynamic—intrinsic muscles of foot and tendons of leg muscles passing into foot

Mnemonics Borders of Popliteal Fossa The two “semi” muscles go together—semimembranosus and semitendinosus. Semi contains an “M”; therefore, they are medial, leaving biceps femoris as the lateral border. Borders of Femoral Triangle So I May Always Love Sally: Superior: Inguinal ligament Medial: Adductor longus Lateral: Sartorius

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CLINICAL ANATOMY FOR YOUR POCKET Psoas major muscle (cut) Iliacus muscle Femoral nerve

Anterior superior iliac spine Inguinal ligament Lateral femoral cutaneous nerve Iliopsoas muscle

Common iliac artery and vein (cut) External iliac artery and vein (cut) Internal iliac artery and vein (cut) Femoral sheath Great saphenous vein (cut) Femoral artery and vein Pectineus muscle

Sartorius muscle Fascia lata (cut)

Femoral triangle (outlined) Adductor longus muscle

FIGURE 5-3. Femoral triangle, anterior view. (From Tank PW, Gest TR. LWW Atlas of Anatomy. Baltimore: Lippincott Williams & Wilkins; 2009:104.)

Contents of Femoral Triangle NAVEL femoral Nerve femoral Artery femoral Vein Empty space, containing Lymphatics

Clinical Significance Femoral Ring The “empty space” of the mnemonic is the femoral canal; the proximal opening of the femoral canal is the femoral ring, a common site for a femoral hernia.

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Superficial structures of the lower limb Structure Course/Significance Vessel Great saphenous • Origin: dorsal digital vein of 1st digit and the dorsal vein venous arch • Runs anterior to medial malleolus, posterior to medial femoral condyle • Passes through saphenous opening to enter femoral vein Small saphenous • Origin: dorsal digital vein of 5th digit and the dorsal vein venous arch • Runs posterior to lateral malleolus superiorly along posterior aspect of the leg • Pierces the deep fascia to enter the popliteal vein in the popliteal fossa Dorsal venous Highly variable superficial venous network on dorsum of arch foot Perforating veins Drain venous blood from superficial veins to deep veins Lymphatics of Superficial lymphatic vessels accompany veins to enter lower limb superficial lymph nodes, including popliteal, inguinal, and external iliac groups Cutaneous Nerve Subcostal • Origin: T12 • Lateral cutaneous branch is sensory to skin of hip Genitofemoral • Origin: lumbar plexus • Sensory to skin of femoral triangle Iliohypogastric • Origin: lumbar plexus • Lateral cutaneous branch is sensory to skin of superolateral gluteal region Ilioinguinal • Origin: lumbar plexus • Femoral branch is sensory to skin of femoral triangle Lateral cutan• Origin: lumbar plexus eous nerve of • Sensory to skin of lateral and anterior thigh thigh Obturator Cutaneous branch sensory to skin of medial aspect of thigh Femoral Cutaneous branch sensory to skin of anterior and medial thigh Saphenous • Origin: femoral • Sensory to skin of medial aspect of leg • Runs with great saphenous vein Lateral sural • Origin: common fibular cutaneous • Sensory to skin of posterolateral leg Medial sural • Origin: tibial cutaneous • Sensory to skin of posterior leg and lateral ankle and foot Sural • Origin: tibial and common fibular • Sensory to skin of posterolateral leg (continued)

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Superficial structures of the lower limb (continued) Structure Superficial fibular

Course/Significance • Origin: common fibular • Sensory to skin of anterolateral leg and dorsal aspect of foot Deep fibular • Origin: common fibular • Sensory to skin between the 1st and 2nd digit on the dorsum of the foot Clunials • Superior, middle, and inferior • Origin: lumbar and sacral plexuses and branches of the posterior cutaneous nerve of the thigh • Sensory to skin of gluteal region Posterior • Origin: sacral plexus cutaneous nerve • Sensory to skin of posterior aspect of thigh of thigh Lateral plantar • Origin: tibial • Sensory to skin of lateral aspect of sole of foot Medial plantar • Origin: tibial • Sensory to skin of medial aspect of sole of foot Tibial Calcaneal branches are sensory to skin over calcaneus

Clinical Significance Nerve Block The ilioinguinal and iliohypogastric nerves can be blocked by injecting anesthetic near the anterior superior iliac spine; the femoral can be blocked near the midpoint of the inguinal ligament. Great Saphenous Vein The great saphenous vein and its tributaries may become varicose, mainly from incompetent valves. During saphenous cutdown, an incision is made anterior to the medial malleolus to locate the great saphenous vein for infusion of therapeutic agents. Fascia of lower limb Fascia/ Connective Tissue Fascia lata Iliotibial tract

Significance/Structure Deep fascia of the thigh • Thickening of fascia lata over lateral aspect of thigh • Extends from iliac tubercle to lateral condyle of tibia • Attachment for tensor fascia lata and gluteus maximus (continued)

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Fascia of lower limb (continued) Fascia/ Connective Tissue

Significance/Structure

Saphenous opening

• Hiatus in the fascia lata inferior to the medial aspect of inguinal ligament • Falciform margin (lateral and inferior) is sharp • Covered by cribriform fascia • Great saphenous vein passes through to enter femoral vein

Falciform margin

Sharp inferior and lateral borders of saphenous opening

Cribriform fascia

Membranous layer of subcutaneous tissue that covers the saphenous opening

Crural fascia

Deep fascia of the leg

Extensor retinacula

Thickened crural fascia over distal leg

Femoral sheath

• Extension of transversalis fascia through subinguinal space into the femoral triangle • Divided into 3 compartments that transmit femoral artery, vein, and femoral canal between the abdominopelvic cavity and femoral triangle of the thigh

Femoral canal

• Medial-most of the 3 compartments of the femoral sheath • Contains fat and lymphatics • Allows for expansion of femoral vein during increased venous return

Popliteal fascia

Deep fascia forming roof of popliteal fossa

Plantar fascia

• Deep fascia of sole of foot • Thickened central aspect forms plantar aponeurosis • Protects sole of foot and supports arches

Plantar aponeurosis

• Thickened central region of plantar fascia • Reinforced distally by superficial transverse metatarsal ligament • Vertical septa extend superiorly from aponeurosis to divide foot into 3 compartments: 1. Medial 2. Central 3. Lateral

Additional Concept Fourth Compartment Distally, a fourth compartment—the interosseous compartment of the foot exists.

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Clinical Significance Compartment Syndrome Increased pressure in the fascial compartments of the lower limb produces compartment syndromes, causing pain and tissue damage. Plantar Fasciitis Inflammation of the plantar aponeurosis—plantar fasciitis, results from high-impact exercise and causes pain over the heel and medial aspects of the foot. Lumbosacral plexus Nerve Roots Divisions

Significance/Structure L1–S4 spinal nerves’ anterior rami form plexus Rami terminate by dividing into an anterior and posterior divisions Branches (6): 1. Femoral nerve (L2–L4) 1. Femoral nerve 2. Obturator nerve (L2–L4) 2. Obturator nerve 3. Common fibular nerve (L4–S2; terminates by 3. Common fibular nerve dividing into superficial and deep fibular nerves) 4. Tibial nerve 4. Tibial nerve (L4–S3) 5. Superior gluteal nerve • 1–4 above innervate the lower limb 6. Inferior gluteal nerve 5. Superior gluteal nerve (L4–S1) 6. Inferior gluteal nerve (L5–S2) • 5–6 above innervate the gluteal region • The common fibular and tibial nerves comprise the sciatic nerve

Clinical Significance Femoral Nerve Injury to the femoral nerve results in the loss of leg extension and therefore loss of the knee jerk reflex. Common Fibular Nerve Loss of dorsiflexion and eversion of the foot as a result of common fibular nerve damage leads to foot drop and foot slap. Superior Gluteal Nerve Injury to the superior gluteal nerve results in paralysis of gluteus medius and minimus, resulting in the inability to steady the pelvis during walking, leading to a positive Trendelenburg sign and a waddling gait.

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Inferior Gluteal Nerve Paralysis of the gluteus maximus, as occurs with injury to the inferior gluteal nerve results in weakness when extending the thigh/hip, leading to difficulty rising from a seated position and climbing stairs. Joints of lower limb (Figure 5-5) Joint Hip

Femorotibial (knee)

Type Synovial

Articulation Structure Head of • Iliofemoral femur with (anterior), acetabulum pubofemoral (inferior), and ischiofemoral (posterior) ligaments support joint • Acetabular labrum and transverse acetabular ligament deepen socket • Ligamentum teres carries the artery to the head of the femur Medial and • 5 extracaplateral femoral sular ligacondyles with ments: medial and 1. Patellar lateral condy- 2. Fibular les of tibia collateral 3. Tibial collateral 4. Oblique popliteal 5. Arcuate popliteal • 4 intraarticular ligaments/ structures: 1. Anterior cruciate

Movements Flexion, extension, abduction, adduction, medial rotation, lateral rotation, and circumduction

Flexion, extension, medial rotation, and lateral rotation

(continued)

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Joints of lower limb (continued) Joint

Type

Superior • Superior: tibiofibular synovial and tibio- • Inferior: fibular syn- fibrous desmosis (inferior)

Talocrural Synovial (ankle)

Articulation Structure 2. Posterior cruciate 3. Medial menisci 4. Lateral menisci • Popliteus tendon strengthens the joint • Superior: • Superior: head of anterior and fibula with posterior tibial ligaments of condyle the head of • Inferior: the fibula fibula with strengthen tibia joint capsule • Inferior: interosseous membrane and anterior and posterior tibiofibular and inferior transverse tibiofibular ligament strengthen joint Medial malle- • Lateral olus and distal ligament: end of tibia calcaneoand lateral fibular, anmalleolus of terior, and fibula with posterior the trochlea talofibular of the talus • Medial (deltoid) ligament: anterior and posterior tibiotalar, tibionavicular, and tibiocalcaneal strengthen and stabilize joint

Movements

Small amount of movement during dorsiflexion

Dorsiflexion, plantarflexion

(continued)

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Joints of lower limb (continued) Joint

Type

Articulation Structure

Movements

Talocalcaneal (subtalar)

Inferior surface of talus with superior surface of calcaneus

• Interosseous Inversion, talocalca- eversion neal ligament binds bodies of calcaneus and talus • Medial, lateral, and posterior talocalcaneal ligament supports joint

Intertarsal (talocalcaneonavicular, calcaneocuboid, cuneonavicular)

Between adjacent tarsal bones

Ligaments, Mainly gliding named for the movements bones they connect, support joint

Tarsometatarsal

Distal tarsal bones with proximal end of metatarsals

Interosseous Gliding tarsometarsal, dorsal, and plantar ligaments strengthen joint

Metatarsophalangeal

Head of metatarsals with proximal phalanges

Plantar and collateral ligaments support joint

Flexion, extension, abduction, adduction, and circumduction

Interphalangeal

Heads of proximal phalanges articulate with more distal phalanges

Plantar and collateral ligaments support joint

Flexion, extension

Additional Concept The inferior tibiofibular joint is the inferiormost part of the tibiofibular syndesmosis.

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CLINICAL ANATOMY FOR YOUR POCKET Peroneus brevis muscle and tendon Fractured fibula Tor n anterior talofibular ligament Avulsion of fifth metatarsal

Fibula

Medial malleolus

Inversion of foot Cuboid

Tal us

Tuberosity of 5th metatarsal

FIGURE 5-4. Inversion injury. Inversion injuries are more common owing to the strength of the deltoid ligament (medial collateral) on the medial side of the ankle; they are most likely to occur during dorsiflexion, when the ankle is most unstable. (From Dudek RW, Louis TM. High-Yield Gross Anatomy. 3rd ed. Baltimore: Lippincott Williams & Wilkins; 2008:256.)

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Femur

Posterior cruciate ligament Anterior cruciate ligament Medial meniscus

Lateral meniscus

Tibia

FIGURE 5-5. Knee magnetic resonance image (coronal section through the intercondylar notch). (From Dudek RW, Louis TM. High-Yield Gross Anatomy. 3rd ed. Baltimore: Lippincott Williams & Wilkins; 2008:253.)

Clinical Significance Hip Dislocation Congenital dislocation of the hip joint is common, particularly in girls. Knee Injuries Anterior cruciate ligament rupture allows the tibia to slide anteriorly relative to the femur—anterior drawer sign; posterior cruciate ligament rupture allows the tibia to slide posteriorly relative to the femur—posterior drawer sign. Mnemonic Structures Posterior to Medial Malleolus From anterior to posterior—Tom, Dick And Very Nervous Harry Tibialis posterior extensor Digitorum longus posterior tibial Artery posterior tibial Vein tibial Nerve

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Upper Limb

INTRODUCTION The upper limb is divided for descriptive purposes by skeletal elements into: ■ ■ ■ ■

shoulder—portion between the arm and the thorax that includes the pectoral girdle: scapula and clavicle arm—portion between the shoulder and elbow that includes the humerus forearm—portion between the elbow and wrist that includes the radius and ulna hand—portion distal to the wrist that includes the metacarpals and phalanges, the carpal bones form the wrist

SHOULDER REGION Bones of the shoulder (Figure 6-1) Bone Clavicle

Feature Shaft

Acromial end Sternal end Scapula

Spine

Significance • S-shaped, serves as strut to suspend limb away from body • Protects neurovascular bundle serving upper limb • Attachment for pectoralis major— clavicular head, sternocleidomastoid— clavicular head, trapezius, subclavius, and deltoid Articulates with the acromion of the scapula at acromioclavicular joint Articulates with the manubrium of the sternum at sternoclavicular joint • Divides posterior aspect of scapula into supra- and infraspinous fossae • Attachment for trapezius and deltoid (continued)

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Bones of the shoulder (continued) Bone

Feature Supraspinous fossa Infraspinous fossa Subscapular fossa Acromion

Glenoid fossa

Supraglenoid tubercle Infraglenoid tubercle Coracoid process

Suprascapular notch

Inferior angle Medial border

Superior angle Lateral border

Significance Attachment for supraspinatus Attachment for infraspinatus Attachment for subscapularis • Expanded, lateral end of spine, forms “point” of the shoulder • Articulates with acromial end of clavicle • Attachment for trapezius and deltoid • Articulates with head of humerus at glenohumeral joint • Deepened by glenoid labrum Attachment for long head of biceps brachii Attachment for long head of triceps brachii • Attachment for biceps brachii (short head), coracobrachialis, and pectoralis minor muscles • Attachment for coracoclavicular and coracoacromial ligaments and the costocoracoid membrane • Transmits the suprascapular nerve • Bridged by the superior transverse scapular ligament • The omohyoid attaches medial to the notch Attachment for teres major and serratus anterior Attachment for levator scapulae, rhomboids (major and minor) and serratus anterior Attachment for levator scapulae Attachment for teres minor

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CLINICAL ANATOMY FOR YOUR POCKET Bones of pectoral girdle

Clavicle Scapula Coracoid process

Superior angle

Acromion Lesser tubercle

Sternal end

Greater tubercle

Medial border Inferior angle Humerus

Deltoid tuberosity

Lateral border

Shaft (body)

Anatomical neck of humerus

Lateral epicondyle Capitulum

Medial epicondyle

Head

Trochlea

Tuberosity

Coronoid process Shaft (body)

Radius Shaft (body) Styloid process Proximal phalanx Distal phalanx

Ulna

Head Styloid process Carpal bones Metacarpal bones (1st) Proximal (2nd) Middle (3rd) Distal

Phalanges

FIGURE 6-1. All bones, upper limb, anterior view.The right superior appendicular skeleton includes the right half of the pectoral (shoulder) girdle, composed of the right clavicle and scapula, and the skeleton of the free right upper limb, formed by the remaining bones distal to the scapula. (From Moore KL, Dalley AF. Clinically Oriented Anatomy. 5th ed. Baltimore: Lippincott Williams & Wilkins; 2006:728.)

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Thyrocervical trunk

Axiallary artery Thoracoacromial artery Circumflex humeral arteries: Posterior Anterior Subscapular artery

Superior thoracic artery Lateral thoracic atery

Deep brachial artery

Thoracodorsal artery Brachial artery

Posterior interosseous artery Radial artery

Common interosseous artery

Anterior interosseous artery Ulnar artery

Deep palmar arch Superficial palmar arch

FIGURE 6-2. Arteries of upper limb, anterior view. (From Tank PW, Gest TR. LWW Atlas of Anatomy. Baltimore: Lippincott Williams & Wilkins; 2009:75.)

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Coracoid process Superior border Superior angle Site of acromioclavicular Spine of of scapula joint scapula Clavicle of scapula Acromion Tubercle of 1st rib Shoulder joint Greater tubercle

Vertebral border of scapula

Deltoid muscle Surgical neck of humerus Infraglenoid tubercle Axillary fat Lateral border of scapula

Anteroposterior View

FIGURE 6-3. Shoulder bone radiograph. (From Dudek RW, Louis TM. High-Yield Gross Anatomy. 3rd ed. Baltimore: Lippincott Williams & Wilkins; 2008:230.)

Clinical Significance Fractures The clavicle, the first bone to begin ossification, is one of the most commonly fractured bones. Fracture is usually evident by the palpable elevation of the medial portion from action of the sternocleidomastoid and drooping of the shoulder from the unsupported weight of the upper limb. Muscles of the shoulder Muscle Pectoralis major

Proximal Attachment • Clavicular head— medial half of clavicle • Sternal head— sternum, superior 6 costal cartilages

Distal Attachment Innervation Medial and Lateral lip intertubercu- lateral lar groove of pectorals humerus

Main Actions • Adducts, flexes, and medially rotates humerus • Draws scapula anteriorly

(continued)

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Muscles of the shoulder (continued) Muscle

Pectoralis minor Serratus anterior

Subclavius

Trapezius

Latissimus dorsi

Proximal Distal Attachment Attachment Innervation and external oblique aponeurosis Coracoid Medial Ribs 3–5 process of pectoral scapula Medial Long thoracic Ribs 1–8 border of scapula

Junction of 1st rib and costal cartilage Superior nuchal line, external occipital protuberance, nuchal ligament, C7–C12 spinous processes T6–T12 spinous processes, thoracolumbar fascia, iliac crest, and ribs 9–12 C1–C4 transverse processes

Stabilizes scapula • Protracts and rotates scapula • Holds scapula against thoracic wall Depresses clavicle

Middle 1⁄3 of clavicle

Nerve to subclavius

Lateral 1⁄3 of clavicle, acromion, spine, of scapula

Spinal accessory

Floor of intertubercular groove of humerus

Thoracodorsal Extends, adducts, medially rotates humerus

Medial border Dorsal and superior scapular angle of scapula Rhomboids— • Major— • Major— medial T2–T5 major border of spinous and minor scapula processes Levator scapulae

Main Actions

• Elevation, depression, retraction of scapula • Rotates glenoid fossa superiorly

Elevates scapula

(continued)

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Muscles of the shoulder (continued) Muscle

Deltoid

Proximal Distal Attachment Attachment Innervation • Minor— • Minor— spine of nuchal scapula ligament C7–T11 spinous processes Deltoid • Clavicle • Acromion tuberosity of and spine humerus of scapula

Supraspinatus Supraspin- Greater ous fossa of tubercle of humerus scapula

Infraspinatus

Infraspinous fossa of scapula

Teres minor

Lateral border of scapula

Teres major

Inferior angle of scapula

Axillary

Main Actions Retract and rotate scapula

Flexes and medially rotates (anterior part), abducts (middle part), extends and laterally rotates (posterior part) arm

Suprascapular • Initiates abduction of arm • Rotator cuff muscle • Laterally rotates arm • Rotator cuff muscle Axillary

Medial lip of intertubercular groove of humerus

Subscapularis Subscapular Lesser tubercle of fossa of humerus scapula

Lower subscapular

Adducts and medially rotates arm

Upper and lower subscapular

• Adducts and medially rotates arm • Rotator cuff muscle

Clinical Significance Serratus Anterior Paralysis When serratus anterior is paralyzed owing to injury of the long thoracic nerve, the medial border moves laterally and posteriorly away from the thoracic wall, giving the scapula the appearance of a wing—winged scapula.

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Mnemonics Long Thoracic Nerve C5–C7, raise your wings to heaven. C5–C7 (cord levels found within the serratus anterior) injury causes inability to “raise” arm past 90 degrees (to heaven) and results in a winged scapula. SALT—Serratus Anterior; Long Thoracic nerve Rotator Cuff The humeral head SITS in the glenoid fossa because of the rotator cuff muscles—Supraspinatus, Infraspinatus, Teres Minor, Subscapularis. Nerves of the shoulder Nerve

Origin

Structures Innervated

Supraclavicular Cervical plexus (C3–C4) nerves

Sensory to skin of shoulder

Axillary

Teres minor, shoulder joint, deltoid, skin of shoulder

Posterior cord

Dorsal scapular C5

Rhomboids, levator scapulae

Spinal accessory 1st few cervical spinal (CN XI) cord segments

Trapezius and sternocleidomastoid

Clinical Significance Axillary Nerve The deltoid atrophies when the axillary nerve is damaged, as happens during fracture of the surgical neck of the humerus or inferior dislocation of the glenohumeral joint. A loss of sensation over the proximal arm accompanies atrophy of the deltoid. Vessels of the shoulder (Figure 6-2) Artery Origin Subclavian— • Right— brachiocephalic right and left trunk • Left—arch of the aorta

Description • Ends at lateral border of 1st rib to become the axillary • Gives rise to vertebral, internal thoracic, and thyrocervical trunk (continued)

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Vessels of the shoulder (continued) Artery Internal thoracic

Origin 1st part of subclavian

Thyrocervical trunk

Description Gives rise to anterior intercostals, musculophrenic, superior epigastric, and pericardiacophrenic Gives rise to suprascapular, transverse cervical, inferior thyroid, and ascending cervical Supplies shoulder region

Suprascapular Thyrocervical trunk Transverse cervical Axillary Subclavian at lateral • 1st part—superior thoracic • 2nd part—thoracoacromial, lateral border of 1st rib thoracic • 3rd part—anterior humeral circumflex, posterior humeral circumflex, and subscapular Superior Supplies 1st and 2nd intercostal 1st part of axillary thoracic spaces, serratus anterior Gives rise to pectoral, deltoid, Thoracoacro- 2nd part of axillary acromial, and clavicular branches mial Supplies lateral aspect of breast Lateral thoracic Supplies area around neck of humerus 3rd part of axillary Circumflex humeral (anterior and posterior) Subscapular Gives rise to circumflex scapular and thoracodorsal Supplies scapular region Circumflex Subscapular scapular Supplies latissimus dorsi Thoracodorsal

Additional Concept Venous Drainage Venous drainage generally parallels arterial supply.

Clinical Significance Axillary Artery The axillary artery can be compressed against the humerus or the first rib if profuse bleeding occurs. Branches of the axillary artery contribute to the extensive anastomoses around the scapula, which may serve to protect

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the limb during occlusion or compression of the primary arterial pathways. Aneurysm of the axillary artery may compress the trunks of the brachial plexus, leading to pain and anesthesia in the areas supplied by the affected nerves. Mnemonics Axillary Artery Branches The axillary artery is divided into three parts by the pectoralis minor. The parts correspond to the number of branches: 1. Part 1—proximal to pectoralis minor has one branch: superior thoracic 2. Part 2—deep to pectoralis minor has two branches: thoracoacromial and lateral thoracic arteries 3. Part 3—distal to pectoralis minor has three branches: anterior and posterior humeral circumflex and the subscapular trunk Send The Lord to Say A Prayer—proximal to distal branches off of the axillary artery: Superior Thoracic Thoracoacromial Lateral Thoracic Subscapular Anterior Circumflex Humeral Posterior Circumflex Humeral Thoracoacromial Trunk Branches CAlifornia Police Department—branches of the thoracoacromial trunk: Clavicular Acromial Pectoral Deltoid

ARM REGION Bones of the arm (Figures 6-1, 6-3, and 6-7) Bone Characteristic Humerus Head

Significance Articulates with glenoid fossa of the scapula to form glenohumeral joint (continued)

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Bones of the arm (continued) Bone

Characteristic

Significance

Greater tubercle

• Lateral aspect of humerus • Attachment for supraspinatus, infraspinatus, and teres minor

Lesser tubercle

• Medial aspect of humerus • Attachment for subscapularis

Anatomical neck

Attachment for glenohumeral joint capsule

Surgical neck

• Common site for humeral fracture • Distal to greater and lesser tubercles • Axillary nerve and posterior humeral circumflex artery are found nearby and are subject to injury during fracture at the neck

Intertubercular groove (bicipital groove)

• Located between the greater and lesser tubercles • Transmits tendon of the long head of the biceps brachii • Bridged by the transverse humeral ligament • Lateral lip attachment for pectoralis major • Floor attachment for latissimus dorsi • Medial lip attachment for teres major

Lateral epicondyle

Attachment for common extensor tendon of the forearm and the supinator

Medial epicondyle

Attachment for common flexor tendon of the forearm and pronator teres

Attachment for brachioradialis, extensor Lateral supracondylar ridge carpi radialis longus and medial head of triceps brachii Attachment for brachialis and the medial Medial supracondylar ridge head of triceps brachii Trochlea

Articulates with trochlear notch of ulna

Capitulum

Articulates with head of radius

Radial fossa

Receives the head of the radius during forearm flexion

Olecranon fossa

Receives olecranon of the ulna during forearm extension

Coronoid fossa

Receives coronoid process of ulna during forearm flexion (continued)

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Bones of the arm (continued) Bone

Characteristic Radial (spiral) groove

Deltoid tuberosity

Significance • Transmits the deep brachial artery and radial nerve • Separates the proximal attachments of the lateral head (lateral to groove) and medial head (medial to groove) of the triceps brachii Attachment for deltoid

Mnemonic Intertubercular Groove Muscle Attachments The lady between two majors. Teres major attaches to the medial lip of the intertubercular groove. Pectoralis major attaches to the lateral lip of the intertubercular groove. Latissimus (lady) Dorsi attaches to the floor of the groove, between the two majors.

Clinical Significance Fractures Most humeral fractures occur at the surgical neck, resulting in an impacted fracture. A fall on the acromion may result in an avulsion fracture in which the greater tubercle is pulled away from the humerus. A direct blow to the arm may result in a transverse or spiral fracture of the shaft, whereas an intercondylar fracture may occur during a fall on a flexed elbow. Muscles of the arm Muscle Coracobrachialis Biceps brachii

Proximal Attachment Coracoid process

• Long head— supraglenoid tubercle • Short head— coracoid process Brachialis Distal humerus, including medial supracondylar ridge

Distal Attachment Humerus

Radial tuberosity

Ulnar tuberosity

Main Innervation Actions Musculocutaneous Flexes and adducts arm Musculocutaneous Flexes arm and forearm, supinates

Musculocutaneous Flexes forearm

(continued)

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Muscles of the arm (continued) Proximal Attachment • Long head— infraglenoid tubercle • Lateral head— lateral to radial groove • Medial head— medial to radial groove, medial and lateral supracondylar ridges Anconeus Lateral epicondyle Muscle Triceps brachii

Distal Attachment Olecranon process

Olecranon process

Innervation Radial

Radial

Main Actions Extends forearm

Extends forearm

Mnemonic Biceps Brachii Attachments You ride shorter to the street corner and ride longer on the superhighway.— Short head of the biceps brachii attaches to the coracoid process. Long head of the biceps brachii attaches to the supraglenoid tubercle.

Clinical Significance Tendonitis of the Biceps Brachii Biceps tendonitis, inflammation of the tendon of the long head, is the result of repetitive movement of the tendon in the intertubercular groove, as occurs in sports that involve throwing. Rupture of the tendon may occur as the tendon is torn from the supraglenoid tubercle. Nerves of the arm Nerve Origin Dorsal scapular C5 Long thoracic Superior trunk Suprascapular Nerve to subclavius

Structures Innervated Rhomboids, levator scapulae Serratus anterior Supraspinatus and infraspinatus Subclavius (continued)

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Nerves of the arm (continued) Nerve Origin Lateral pectoral Lateral cord Musculocutaneous Median

Lateral cord and medial cord

Medial pectoral Ulnar

Medial cord

Upper subscapular Posterior cord Lower subscapular Thoracodorsal Axillary

Radial

Structures Innervated Pectoralis major • Anterior compartment of the arm • Sensory to lateral forearm • Anterior compartment of the forearm (except flexor carpi ulnaris and the ulnar half of flexor digitorum profundus), muscles of the thenar eminence and the first 2 lumbricals Pectoralis minor and major • Flexor carpi ulnaris and the ulnar half of flexor digitorum profundus • Most muscles of the hand • Sensory to hand medial to digit 4 Subscapularis Subscapularis and teres major Latissimus dorsi • Teres minor, deltoid • Shoulder joint, sensory to skin over shoulder • Posterior compartments of arm and forearm • Sensory to skin of posterior arm, forearm, and hand

Clinical Significance Thoracodorsal Nerve Injury Injury to the thoracodorsal nerve, as may occur during resection of axillary lymph nodes in breast cancer, causes paralysis of the latissimus dorsi. The person is then unable to raise the trunk with the upper limbs or use an axillary crutch. Arm vessels (Figure 6-2) Artery Axillary

Origin Subclavian at lateral border of 1st rib

Description • 1st part—superior thoracic • 2nd part—thoracoacromial, lateral thoracic • 3rd part—anterior circumflex humeral, posterior circumflex humeral, and subscapular (continued)

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Arm vessels (continued) Artery

Origin

Description

Circumflex 3rd part of axillary humeral (anterior and posterior) arteries

Supplies area around neck of humerus

Subscapular artery

Gives rise to circumflex scapular and thoracodorsal

Circumflex scapular artery

Subscapular

Thoracodorsal artery

Supplies scapular region

Supplies latissimus dorsi

Brachial artery

Axillary after lateral border of teres major

• Continuation of axillary • Terminates in elbow region to form radial and ulnar arteries

Deep brachial artery

Brachial

• Supplies posterior compartment of arm and elbow joint • Runs in radial groove with radial nerve

Superior ulnar collateral artery

Supplies elbow region

Inferior ulnar collateral artery

Additional Concept Venous Drainage Venous drainage generally parallels arterial supply.

Clinical Significance Brachial Artery Compression of the brachial artery is best accomplished along the medial humerus in the mid-arm region. Collateral circulation through the deep brachial artery allows for perfusion distal to the compression.

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FOREARM REGION Bones of the forearm (Figures 6-1 and 6-7) Bone Radius

Characteristic Head

Radial tuberosity Ulnar notch Styloid process Ulna

Olecranon

Coronoid process

Trochlear notch Ulnar tuberosity Radial notch Supinator crest Supinator fossa Head Styloid process

Significance • Articulates with capitulum of humerus and radial notch of ulna • Held in place by the anular ligament Attachment for biceps brachii Articulates with head of ulna Attachment for brachioradialis and radial collateral ligament Attachment for flexor carpi ulnaris (ulnar head), triceps brachii, anconeus, and ulnar collateral ligament • Articulates with coronoid fossa of humerus during flexion • Attachment for pronator teres, flexor digitorum superficialis and ulnar collateral ligament Articulates with trochlea of humerus Attachment for brachialis Articulates with head of radius Attachment for supinator Articulates with ulnar notch of radius and articular disc of the wrist Attachment for ulnar collateral ligament

Clinical Significance Fractures As a result of attempting to break a fall with the outstretched limb a Colles’ fracture may occur. A Colles’ fracture is a transverse fracture of the distal radius, often accompanied by an avulsed styloid process of the ulna. The result is a posterior angulation of the forearm, just proximal to the wrist—a dinner fork deformity. Fractured Elbow Fracture of the olecranon—a fractured elbow, is often caused by a fall. The triceps brachii pulls the avulsed piece of bone in this painful and debilitating injury.

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Muscles of the forearm Muscle Pronator teres

Flexor carpi radialis Palmaris longus

Proximal Attachment Medial epicondyle of humerus and coronoid process of ulna Medial epicondyle of humerus

Medial epicondyle of humerus and olecranon process and posterior ulna Medial Flexor digitorum epicondyle of superficialis humerus and coronoid process of ulna and anterior radius Flexor carpi ulnaris

Ulna and Flexor digitorum interosseous profundus membrane

Flexor pollicis longus Pronator quadratus Brachioradialis

Extensor carpi radialis longus

Distal Attachment Mid-radius

Innervation Median

Flexes wrist and abducts hand Flexes wrist

2nd metacarpal Flexor retinaculum and palmar aponeurosis Pisiform, hook of hamate and 5th metacarpal

Main Actions Pronates and flexes elbow

Ulnar

Flexes wrist and adducts hand

Middle phalanges of medial 4 digits

Median

Distal phalanges of medial 4 digits

Medial part—ulnar; lateral part— median Anterior interosseous (median)

Flexes proximal interphalangeal joints of medial 4 digits and flexes metacarpophalangeal joints and flexes wrist Flexes distal interphalangeal joints of medial 4 digits and flexes wrist Flexes thumb

Radius and interosseous membrane Ulna

Distal phalanx of thumb Radius

Lateral supracondylar ridge of humerus

Styloid process of radius 2nd metacarpal

Pronates Radial

Flexes forearm

Extends hand and abducts wrist (continued)

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Muscles of the forearm (continued) Muscle Extensor carpi radialis brevis Extensor digitorum

Extensor digiti minimi Extensor carpi ulnaris Supinator

Abductor pollicis longus Extensor pollicis longus Extensor pollicis brevis Extensor indicis

Proximal Attachment Lateral epicondyle of humerus

Lateral epicondyle of humerus and ulna Lateral epicondyle of humerus, radial collateral ligament, anular ligament, supinator crest, and fossa of ulna Ulna, radius, and interosseous membrane Ulna and interosseous membrane Radius and interosseous membrane Ulna and interosseous membrane

Distal Attachment 3rd metacarpal

Innervation Deep radial (radial)

Main Actions

Extensor expansion of medial 4 digits 5th digit extensor expansion 5th metacarpal

Posterior interosseous (radial)

Proximal radius

Deep radial (radial)

Supinates

1st metacarpal

Posterior interosseous (radial)

Abducts thumb

Distal phalanx of thumb Proximal phalanx of thumb 2nd digit extensor expansion

Extends medial 4 digits

Extends 5th digit Extends hand and adducts wrist

Extends thumb

Extends 2nd digit

Mnemonics Relationship of Flexor Tendons in the Digits Superficialis splits in two to permit profundus to pass through.

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Relationship of Flexors in the Anterior Forearm Tuck your thumb into your palm; lay your hand on your proximal forearm with the fingers pointed toward your hand.Your fingers represent the top layer of muscles: 2nd digit—pronator teres 3rd digit—flexor carpi radialis 4th digit—palmaris longus 5th digit—flexor carpi ulnaris 1st digit (thumb) represents the intermediate muscle layer—flexor digitorum superficialis

Clinical Significance Elbow Tendonitis Elbow tendonitis, or tennis elbow, is caused by repetitive use of the superficial extensor muscles of the forearm. Forearm nerves Nerve

Origin

Structures Innervated

Median

Union of lateral root (lateral cord) and medial root (medial cord)

Pronator teres, flexor carpi radialis, palmaris longus, and flexor digitorum superficialis

Anterior Median interosseous

Lateral aspect of flexor digitorum profundus, flexor pollicis longus, and pronator quadratus

Ulnar

Medial cord of brachial plexus

Medial aspect of flexor digitorum profundus and flexor carpi ulnaris

Radial

Posterior cord of brachial plexus

Brachioradialis and extensor carpi radialis longus

Deep branch Radial of radial

Extensor carpi radialis brevis, and supinator

Posterior Deep branch of interosseous radial

Extensor digitorum, extensor digiti minimi, extensor carpi ulnaris, abductor pollicis longus, extensor pollicis longus, extensor pollicis brevis, and extensor indicis

Posterior Radial cutaneous nerve of the forearm

Posterior aspect of the forearm

(continued)

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Forearm nerves (continued) Nerve Lateral cutaneous nerve of the forearm Medial cutaneous nerve of the forearm

Origin Musculocutaneous

Structures Innervated Lateral aspect of the forearm

Medial cord of brachial plexus

Medial aspect of the forearm

Mnemonic Radial Nerve The radial nerve innervates the BEST muscles— Brachioradialis Extensors Supinator Triceps Brachii Vessels of the forearm (Figure 6-2) Artery Origin Brachial Ulnar Radial Anterior ulnar recurrent Ulnar Posterior ulnar recurrent Common interosseous Anterior interosseous Common Posterior interosseous interosseous Recurrent interosseous Posterior interosseous Ulnar Palmar carpal branch Dorsal carpal branch Radial Radial recurrent Palmar carpal branch Dorsal carpal branch

Description Terminal branch of the brachial Supplies elbow region Gives rise to anterior and posterior interosseous Supplies anterior aspect of forearm Supplies posterior aspect of forearm Supplies elbow region Contributes to palmar carpal arch Contributes to dorsal carpal arch Supplies elbow region Contributes to palmar carpal arch Contributes to dorsal carpal arch

Additional Concept Venous Drainage Venous drainage generally parallels arterial supply.

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Mnemonic Arterial Anastomosis at Elbow I Am Pretty Smart Inferior ulnar collateral artery anastomoses with the Anterior ulnar recurrent artery. Posterior ulnar recurrent artery anastomoses with the Superior ulnar collateral artery.

HAND REGION Bones of the hand (Figures 6-1 and 6-4) Bone

Characteristic

Significance

Scaphoid Tubercle

• Attachment for abductor pollicis brevis, opponens pollicis, flexor pollicis brevis, radial collateral ligament, and flexor retinaculum (tubercle) • Articulates with radius, trapezium, lunate, capitate, and trapezoid • Most commonly fractured carpal bone

Lunate

Crescent-shaped

• Articulates with radius, scaphoid, triquetrum, capitate, and hamate • Most frequently dislocated carpal bone

Triquetrum

Pyramid-shaped

• Articulates with pisiform, hamate and lunate • Attachment for ulnar collateral ligament

Pisiform

Spheroidal

• Articulates with triquetrum • Attachment for flexor retinaculum, flexor carpi ulnaris, and abductor digiti minimi

Trapezium

Tubercle

• Attachment for flexor retinaculum, opponens pollicis, abductor pollicis brevis, and flexor pollicis brevis • Articulates with scaphoid, 1st and 2nd metacarpals, and trapezoid

Trapezoid Wedge-shaped

Articulates with scaphoid, 2nd metacarpal, trapezium, and capitate

Capitate

Head

• Attachment for adductor pollicis • Articulates with scaphoid; lunate; 2nd, 3rd, and 4th metacarpals; trapezoid; and hamate • Largest carpal bone

Hamate

Hamulus

Attachment for flexor retinaculum, opponens digiti minimi, flexor carpi ulnaris, flexor digiti minimi; articulates with lunate, 4th and 5th metacarpals, triquetrum, and capitate (continued)

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Bones of the hand (continued) Bone Characteristic Metacar- Heads pals (5) Proximal phalanges (5) Middle phalanges (5) Distal Tuberosity phalanges (4)

Significance Articulate with proximal phalanges Articulate with more distal phalanges

Ungual tuberosity supports the fingernail

Scaphoid

Radius

Capitate

Lunate

FIGURE 6-4. Scaphoid fracture. The scaphoid is the most frequently fractured carpal bone; fractures may result from a fall on the palm. (From Dudek RW, Louis TM. High-Yield Gross Anatomy. 3rd ed. Baltimore: Lippincott Williams & Wilkins; 2008:235.)

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Mnemonic Carpal Bones She Looks To Pretty, Try To Catch Her Scaphoid, Lunate, Triquetrum, Pisiform, Trapezium, Trapezoid, Capitate, Hamate The trapezium is nearest the thumb—trapeze-e-thumb.

Clinical Significance Fractures The scaphoid is the most frequently fractured carpal bone and occurs from a fall on the palm when the wrist is abducted. Fracture of the 5th metacarpal, a boxer’s fracture, occurs when an unskilled person punches someone, causing the head of the bone to rotate over the distal shaft. Injuries of the phalanges are common and are extremely painful, often resulting from crush injuries. Muscles of the hand Proximal Muscle Attachment Thenar Muscles Opponens Flexor retinacupollicis lum, trapezium

Distal Attachment

Abductor pollicis

Proximal phalanx of thumb

Flexor pollicis brevis

Adductor pollicis

Flexor retinaculum, trapezium, and scaphoid Flexor retinaculum, and trapezium

• Oblique head—2nd and 3rd metacarpals, capitate and adjacent carpals

1st metacarpal

Innervation

Main Actions

Recurrent branch of median

Rotates and draws 1st metacarpal medially Abducts thumb, helps opposition

• Superficial Flexes thumb head— recurrent branch of median • Deep head—deep branch of ulnar Deep branch Adducts thumb of ulnar

(continued)

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Muscles of the hand (continued) Proximal Distal Attachment Attachment Innervation • Transverse head—3rd metacarpal Hypothenar Muscles Abductor Pisiform Proximal Deep branch digiti phalanx of of ulnar minimi 5th digit Flexor Flexor digiti retinaculum minimi and hamate Opponens 5th metadigiti carpal minimi Short Muscles—Lumbricals and Interossei 1st and Tendons of Extensor Median 2nd lum- flexor digitoexpansions of bricals rum profundus digits 2–5 3rd and Deep branch 4th lumof ulnar bricals Palmar 2nd, 4th, and Proximal phainterossei 5th metacarpals langes and extensor expansions of 2nd, 4th, and 5th digits Muscle

Dorsal interossei

Metacarpals

Proximal phalanges and extensor expansions of 2nd–4th digits

Main Actions

Abducts 5th digit Flexes 5th digit

Opposes 5th digit with thumb

Flex digits at metacarpophalangeal joints and extend at interphalangeal joints • Adduct 2nd, 4th, and 5th digits • Flex digits at metacarpophalangeal joints and extend at interphalangeal joints Abduct 2nd–4th digits; flex digits at metacarpophalangeal joints and extend at interphalangeal joints

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Mnemonics Innervation of Hand Musculature Meat LOAF muscles—Median nerve innervates the first two Lumbricals, Opponens Pollicis, Abductor Pollicis Brevis and Flexor Pollicis Brevis in the hand. Interossei Function PAd and DAb—Palmer interossei Adduct, Dorsal interossei Abduct. Hand nerves Nerve Median

Palmar cutaneous branch of median Ulnar

Palmar cutaneous branch of ulnar Dorsal cutaneous branch of ulnar Superficial branch of radial

Origin Union of lateral root (lateral cord) and medial root (medial cord) Median

Structures Innervated Opponens pollicis, abductor pollicis brevis, superficial head of flexor pollicis brevis, and 1st and 2nd lumbricals

Sensory over palm, sides of digits 1–3, lateral side of 4th digit, and dorsum of of distal aspect of digits 1–4 Medial cord of Opponens digiti minimi, flexor digiti brachial plexus minimi brevis, abductor digiti minimi, 3rd and 4th lumbricals, adductor pollicis, deep head of flexor pollicis brevis, and the palmar and dorsal interossei Ulnar Sensory to medial aspect of palm, 5th digit and medial half of 4th digit Sensory to medial aspect of dorsum, 5th digit and medial half of 4th digit Radial Sensory to lateral 2⁄3 of dorsum of hand, thumb and lateral 11⁄2 digits

Vessels of the hand (Figure 6-2) Artery Superficial palmar arch Deep palmar arch

Origin Description Continuation of the Common palmar digital arteries ulnar with contribution from radial Continuation of the Palmar metacarpal arteries radial with contribution from the ulnar (continued)

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Vessels of the hand (continued) Artery Common palmar digitals Proper palmar digitals Princeps pollicis Radialis indicis Dorsal carpal arch Palmar carpal arch

Origin Superficial palmar arch Common palmar digitals Radial Radial and ulnar

Description Proper palmar digitals Supplies digits Supplies thumb Supplies 2nd digit Supplies wrist

Additional Concept Venous Drainage Venous drainage generally parallels arterial supply. Palmar Arches The superficial palmar arch is more distal (in line with the distal margin of the extended thumb); the deep arch is more proximal.

Clinical Significance Palmar Arch Bleeding is usually profuse and difficult to control when the palmar arches are lacerated. Often, it is necessary to compress the brachial artery in the arm to limit the bleeding.

MISCELLANEOUS Areas of the upper limb Area Axilla

Structure Significance 4-sided, fat-filled, pyramidal • Permits passage of neurospace inferior to glenohumeral vascular elements to and joint and superior to axillary fascia: from the upper limb— • Apex: cervicoaxillary canal— contains axillary artery and passageway between neck vein, major portion of the and axilla brachial plexus, and lymph • Base: axillary fascia nodes • Anterior wall: pectoralis major and minor (continued)

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Areas of the upper limb (continued) Area

Quadrangular space

Upper triangular space

Lower triangular space

Cubital fossa

Carpal tunnel

Deltopectoral triangle Anatomic snuff-box

Structure • Posterior wall: subscapularis, teres major, and latissimus dorsi • Medial wall: thoracic wall and serratus anterior • Lateral wall: humerus Boundaries: • Superior: teres minor • Inferior: teres major • Medial: long head of triceps brachii • Lateral: humerus Boundaries: • Superior: teres minor • Inferior: teres major • Lateral: long head of triceps brachii Boundaries: • Superior: teres major • Medial: long head of triceps brachii • Lateral: medial head of triceps brachii Triangular depression on anterior aspect of elbow, boundaries: • Superior: imaginary line between the medial and lateral epicondyles • Medial: pronator teres • Lateral: brachioradialis • Floor: brachialis • Roof: bicipital aponeurosis Cup-shaped (concave anteriorly) passageway from the forearm to the hand; boundaries: • Lateral: scaphoid and trapezoid • Medial: hamate and pisiform • Roof (anterior): flexor retinaculum • Triangular area bounded by the clavicle, deltoid and pectoralis major • Covered by clavipectoral fascia Triangular area bounded medially by the tendon of extensor pollicis longus, laterally by the tendons of extensor pollicis brevis and abductor pollicis longus

Significance • Axillary sheath: extension of cervical (prevertebral) fascia that ensheathes proximal end of neurovascular elements Permits passage of the axillary nerve and posterior humeral circumflex artery to posterior aspect of shoulder

Permits passage of the circumflex scapular artery to posterior aspect of shoulder

Permits passage of radial nerve and deep brachial artery to posterior aspect of arm

• Contains: brachial artery and its division into radial and ulnar arteries (and their accompanying deep veins), biceps brachii tendon, and median nerve • Median cubital vein lies superficial to bicipital aponeurosis Conveys the tendons of the flexor digitorum superficialis, flexor digitorum profundus andflexor pollicis longus, and the median nerve Pierced by cephalic vein, branches of the thoracoacromial trunk and lateral pectoral nerve located within • Floor is formed primarily by the scaphoid • Radial artery passes through—the radial pulse may be taken here

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Mnemonic Structures in the Cubital Fossa TAN—structures found within the cubital fossa from lateral to medial: Tendon: biceps brachii Artery: brachial Nerve: median

Clinical Significance Axilla Wounds in the axilla often involve the axillary vein, because of its large size and superficial position. Carpal Tunnel Carpal tunnel syndrome results from anything that limits the space in the carpal tunnel and is characterized by loss of sensation over the first digit, the inability to oppose the thumb, and thenar wasting from the compromised function of the median nerve. Superficial structures of the upper limb Structure Vessel Cephalic vein

Basilic vein

Median cubital vein Median vein of the forearm Dorsal venous network Lymphatics of upper limb

Course/Significance • Origin: dorsal venous network; runs along lateral aspect of upper limb • Enters deltopectoral triangle, pierces costocoracoid membrane to join axillary vein • Origin: dorsal venous network; runs along medial aspect of upper limb • Pierces the brachial fascia at mid-arm to join with the brachial veins to form the axillary vein • Joins the cephalic and basilic veins over the cubital fossa • Supported by the bicipital aponeurosis • Origin: dorsal venous network • Courses between and enters the cephalic or basilic veins at the elbow Highly variable superficial venous network on dorsum of hand • Superficial lymphatic vessels accompany veins to enter superficial lymph nodes • Includes: cubital and axillary groups (continued)

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Superficial structures of the upper limb (continued) Structure Cutaneous Nerve Supraclavicular nerves Posterior cutaneous nerve of the arm Superior lateral cutaneous nerve of the arm Inferior lateral cutaneous nerve of the arm Intercostobrachial Medial cutaneous nerve of the arm Medial cutaneous nerve of the forearm Posterior cutaneous nerve of the forearm Lateral cutaneous nerve of the arm Lateral cutaneous nerve of the forearm Terminal branches of the median Terminal branches of the radial Terminal branches of the ulnar

Course/Significance • Origin: cervical plexus (C3–C4) • Sensory to skin of shoulder • Origin: Radial nerve • Sensory to skin of posterior aspect of arm • Origin: continuation of axillary nerve • Sensory to lateral aspect of arm (proximally) • Origin: radial nerve • Sensory to skin over lateral aspect of arm (distally) • Origin: 2nd intercostal nerve • Sensory to medial aspect of arm • Origin: medial cord • Sensory to medial aspect of arm • Origin: medial cord • Sensory to medial aspect of forearm • Origin: radial nerve • Sensory to posterior aspect of forearm • Origin: axillary nerve • Sensory to lateral aspect of arm • Origin: continuation of musculocutaneous • Sensory to the lateral aspect of the forearm Sensory over palm, sides of digits 1–3, lateral side of 4th digit, and dorsum of distal aspect of digits 1–4 Sensory to lateral 2⁄3 of dorsum of hand, thumb, and lateral 11⁄2 digits Sensory to medial aspect of palm and dorsum, 5th digit, and medial half of 4th digit

Clinical Significance Median Cubital Vein The median cubital vein is the common vein selected for venipuncture because of its accessibility and superficial relationship to the bicipital aponeurosis, which supplies some protection to the underlying brachial artery.

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C2

C3

C5

C4

C7 T1

C5 T1 T2 T3 T4 T5 T6 T7 T8 T9

C5 T1 C6

L1

C8 C7

C3 C4 C6 C8 T2

T3

T4

T5

T6

T7

T8

T9

T10

T11

T12

L1

T10

L3

T11 T12

L5

L2 L4 S1 S2 S3 S4 S5

L2 S2 S1 L3

L1 L2

L4

L3

L5

S1

L4 L4 L5

Anterior view

Posterior view

FIGURE 6-5. Dermatome maps of the body are based on accumulation of clinical findings following spinal nerve injuries; this map is based on the studies of Keegan and Garrett (1948). Spinal nerve C1 lacks a significant afferent component and does not supply the skin; therefore, no C1 dermatome is depicted. (From Moore KL, Dalley AF. Clinically Oriented Anatomy. 5th ed. Baltimore: Lippincott Williams & Wilkins; 2006:53.)

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Fascia of the upper limb Fascia/ Connective Tissue Pectoral Axillary Clavipectoral Costocoracoid membrane

Suspensory ligament of the axilla Deltoid fascia Brachial fascia

Antebrachial fascia

Extensor retinaculum

Flexor retinaculum Palmar fascia Superficial transverse carpal ligament

Significance/Structure Investing fascia of pectoralis major Forms floor of axilla Encloses subclavius and pectoralis minor • Clavipectoral fascia between pectoralis minor and subclavius • Pierced by lateral pectoral nerve • Clavipectoral fascia inferior to pectoralis minor • Supports axillary fascia and forms axillary fossa on abduction Investing fascia of deltoid is continuous with pectoral and infraspinous fascia • Sheath of deep fascia surrounding arm • Attaches distally to humeral condyles and olecranon process of ulna • Continuous with antebrachial, pectoral, deltoid, axillary, and infraspinous fasciae • Gives rise to medial and lateral intermuscular septa, which divide arm into anterior and posterior compartments • Sheath of deep fascia surrounding forearm • Continuous with brachial fascia • Intermuscular septa and the interosseous membrane divide the forearm into anterior and posterior compartments Posterior thickening of antebrachial fascia over distal ulna and radius—holds extensor tendons in place Anterior thickening of antebrachial fascia over carpal bones—forms carpal tunnel • Continuous with antebrachial fascia • Central portion—palmar aponeurosis Forms base of palmar aponeurosis

Brachial plexus (Figure 6-6) Nerve Roots

Significance/Structure • Anterior rami of C5–T1 • C5 gives rise to the dorsal scapular nerve and nerve to subclavius • C5–C7 give rise to the long thoracic nerve (continued)

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Brachial plexus (continued) Nerve

Significance/Structure

Superior trunk

• Formed by the C5 and C6 roots • Gives rise to the nerve to subclavius and the suprascapular nerve

Middle trunk

Continuation of C7 root

Inferior trunk

Formed by the C8 and T1 roots

Divisions

• Each trunk terminates by dividing into an anterior and a posterior division • No branches off the divisions

Lateral cord

• Formed by junction of anterior divisions from the superior and middle trunks • Lateral to axillary artery • Gives rise to the lateral pectoral nerve • Terminates by dividing into the musculocutaneous nerve and lateral root of the median nerve

Posterior cord

• Formed by the posterior divisions of all 3 cords • Posterior to axillary artery • Gives rise to the upper and lower subscapular and thoracodorsal nerves • Terminates by dividing into the axillary and radial nerves

Medial cord

• Formed by the anterior division of the inferior trunk • Medial to axillary artery • Gives rise to the medial pectoral, medial brachial cutaneous, and medial antebrachial cutaneous nerves • Terminates by dividing into the ulnar nerve and the medial root of the median nerve

Mnemonics Parts of the Brachial Plexus From proximal to distal: Real—Roots Truckers—Trunks Drink—Divisions Cold—Cords Beer—Branches Terminal Branches of the Brachial Plexus Terminal branches lateral to medial— My Audi Races My Uncle. Musculocutaneous, Axillary, Radial, Median, Ulnar

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CLINICAL ANATOMY FOR YOUR POCKET 5 Roots (ventral rami of spinal nerves C5–T1) Dorsal scapular nerve (C5)

3 Trunks

C5 contribution to phrenic nerve

3 Anteiror divisions 3 Posterior divisions Suprascapular nerve (C5–C6)

C5

Nerve to subclavius muscle (C5–C6)

C6

To longus colli and scalene muscles C8 (C5–C8) C7

Superior

3 Cords around axillary artery

Middle Inferior

Terminal branches

T1

Lateral pectoral nerve (C5–C7) 1st rib

Lateral Posterior Medial

Long thoracic nerve (C5–C7)

1st intercostal nerve Medial pectoral nerve (C8, T1) Medial brachial cutaneous nerve (T1) Medial antebrachial cutaneous nerve (C8, T1)

Musculocutaneous nerve (C5–C7) Axillary nerve (C5–C6) Median nerve (C5–C8, T1)

Dorsal ramus

Upper subscapular nerve (C5–C6) Thoracodorsal (middle subscapular) nerve (C6–C8) Lower subscapular nerve (C5–C6) Ulnar nerve (C7–C8, T1) Radial nerve (C5–C8, T1)

FIGURE 6-6. Brachial plexus. (From Tank PW, Gest TR. LWW Atlas of Anatomy. Baltimore: Lippincott Williams & Wilkins; 2009:43.)

Pectoral Nerves Lateral Less, Medial More—The Lateral pectoral nerve only passes through the pectoralis major, whereas the Medial pectoral nerve passes through both pectoralis major and minor. Branches of the Posterior Cord Branches off the posterior cord: STAR—Subscapulars (upper and lower), Thoracodorsal, Axillary, Radial Identification Tip The musculocutaneous, median, and ulnar nerves form an “M” on the anterior aspect of the axillary artery, making their identification a good starting point for the region.

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Brachial Plexus Variations Variations in the form of the brachial plexus are common and may include contributions from additional anterior rami such as C4 or T2 or alterations in the branches, divisions, cords, or trunks.

Clinical Significance Brachial Plexus Injuries Injuries to the superior parts of the brachial plexus usually result from an excessive increase in the angle between the neck and shoulder, as occurs during a fall increasing the angle between the two or excessive stretching of a baby’s head and neck during delivery. Injury to the superior part of the plexus is apparent by the characteristic “waiter’s tip” position, in which the limb is medially rotated, the shoulder adducted and the elbow extended. Injuries to the inferior parts of the brachial plexus occur when the upper limb is pulled superiorly, as in grasping something to break a fall or a baby’s upper limb is pulled during delivery. The intrinsic muscles of the hand are involved, resulting in claw hand.

Injury to the Terminal Branches Musculocutaneous Nerve Musculocutaneous nerve injury results in paralysis of the muscles in the anterior compartment of the arm and therefore weakening of elbow flexion and supination, as well as loss of sensation over the lateral forearm. Radial Nerve Injury to the radial nerve may result in “wrist drop” as a result of the loss of wrist extensors and the unopposed actions of the flexor muscles. Median nerve When the median nerve is compromised at the elbow, the 2nd and 3rd digits remain partially extended on attempting to make a fist—the “hand of the benediction.” Ulnar Nerve The ulnar nerve may be compromised as it passes posterior to the medial epicondyle, resulting in the characteristic “claw hand,” combined with sensory loss over the medial aspect of the palm.

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Joints of the upper limb (Figure 6-3) Joint Sternoclavicular

Type Articulation Structure Synovial Sternal end of • Anterior, posterior, and clavicle with interclavicumanubrium of lar ligaments sternum and strengthen 1st costal joint cartilage • Costoclavicular ligament attaches clavicle to sternum • Divided into 2 compartments by an articular disk Acromial end • CoracoacroAcromioclavicular mial and of clavicle acromioclavwith icular ligaacromion of ments scapula strengthen joint superiorly • Coracoclavicular ligament (subdivided into trapezoid and conoid) strengthens joint • GlenohuHead of Glenohumeral meral ligahumerus with (shoulder) ments glenoid fossa strengthen of scapula; joint anteriglenoid fossa orly deepened by • Coracohumeglenoid ral ligament labrum strengthens joint superiorly • Transverse humeral ligament forms

Movements Protraction, retraction, elevation, and depression

Rotation of scapula on clavicle related to movement of the scapulothoracic joint

Flexion, extension, abduction, adduction, medial rotation, lateral rotation, and circumduction

(continued)

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Joints of the upper limb (continued) Joint

Type

Scapulothoracic

Physiologic joint

Humeroulnar and humeroradial (elbow)

Synovial Trochlea and capitulum of humerus with trochlear notch of the ulna and the head of the radius Head of radius with radial notch of ulna

Proximal radioulnar joint

Distal radioulnar joint

Articulation Structure canal for tendon of the long head of the biceps brachii • Most joint strength from rotator cuff (supraspinatus, infraspinatus, subscapularis, and teres minor) • No bone to Thoracic bone articuwall with lation scapula and • Site of associated scapula movstructures ing on thoracic wall

Head of ulna with ulnar notch of radius

Movements

Elevation, depression, protraction, retraction, and rotation

Radial and Flexion, ulnar collateral extension ligaments strengthen the joint on the lateral and medial aspects Anular ligament of the radius holds the radial head in radial notch of ulna Anterior and posterior ligaments strengthen joint

Supination, pronation by rotation of the radial head Supination, pronation by distal radius rotating around ulnar head (continued)

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Joints of the upper limb (continued) Joint Radiocarpal (wrist)

Intercarpal

Carpometacarpal

Type

Articulation Structure Distal radius • Anterior and posterior ligwith proximal aments carpal bones strengthen joint • Ulnar collateral attaches to styloid process of ulna and triquetrum • Radial collateral attaches styloid of radius and scaphoid Anterior and Between posterior adjacent carpal bones interosseous ligaments support joint Carpals and metacarpals

Metacarpophalangeal

Head of metacarpals with proximal phalanges

Interphalangeal

Heads of proximal phalanges articulate with more distal phalanges

Movements Flexion, extension, abduction, adduction, and circumduction

Gliding, flexion and abduction at midcarpal Flexion, extension, abduction, and adduction Flexion, extension, abduction, adduction, and circumduction

Palmar ligaments, deep transverse metacarpal, and collateral ligaments support joint Palmar and col- Flexion, extension lateral ligaments support joint

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Humerus

Capitulum Trochlea

Olecranon process

Head of radius Radial tuberosity

Ulna

FIGURE 6-7. Lateral elbow radiograph. (From Dudek RW, Louis TM. High-Yield Gross Anatomy. 3rd ed. Baltimore: Lippincott Williams & Wilkins; 2008:232.)

Mnemonic Elbow Movements Three Bs Bend the elbow— Brachialis Biceps brachii Brachioradialis

Clinical Significance Dislocations Dislocation of the acromioclavicular joint—a shoulder separation, is relatively common in sports or falls that impact the shoulder. Most dislocations of the glenohumeral joint occur inferiorly because of the strong ligamentous and muscular support elsewhere. Subluxation and dislocation of the head of the radius— also known as “nursemaid’s elbow” or “pulled elbow”—is common in children that are suddenly lifted by the upper limb.

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Head

INTRODUCTION The head is that portion of the body that sits on the neck; the skeleton of the head is the cranium (skull), which contains the brain and meninges.

CRANIUM Cranial bone summary The cranium is divided into a neurocranium and a viscerocranium.

Neurocranium ■ ■ ■

encases the brain roof—calvarium; floor—cranial base formed of bones: frontal, ethmoid, sphenoid, occipital, temporal (2), and parietal (2)

Viscerocranium ■ ■

skeleton of the face formed of 15 bones: mandible, maxilla (2), inferior nasal concha (2), nasal (2), lacrimal (2), vomer, ethmoid, zygomatic (2), and palatine (2)

Bone Zygomatic arch

Feature Prominence of cheekbone

Hard palate

Bony anterior aspect of palate

Significance Formed by union of temporal process of zygomatic bone anteriorly and zygomatic process of temporal bone posteriorly Formed by the palatine processes of the maxillae—anterior 2⁄3, and the horizontal plates of the palatine bones—posterior 1⁄3 (continued)

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Cranial bone summary (continued) Bone Frontal

Feature Overall

Supraorbital margin

Parietal (2)

Overall Temporal lines (superior and inferior)

Groove for middle meningeal artery Occipital Overall External occipital protuberance Nuchal lines (superior and inferior) Hypoglossal canal Jugular foramen

Foramen magnum

Groove for transverse sinus Internal occipital protuberance Pharyngeal tubercle Occipital condyles Cribriform plate

Significance • Forms anterior aspect of neurocranium • Skeleton of forehead • Forms roof of orbit and floor of anterior cranial fossa • Anterior superior aspect of orbit • Possesses supraorbital foramen or notch— transmits supraorbital neurovascular elements Form lateral aspects of neurocranium • Proximal attachment for temporalis and its investing fascia • Form superior border of temporal fossa Conveys middle meningeal artery Forms posterior aspect of neurocranium Attachment for ligamentum nuchae Superior—attachment for sternocleidomastoid, trapezius, and splenius capitis Transmits CN XII Shared foramen between occipital and temporal bones that transmits CN IX, X, and XI, and internal jugular vein and inferior petrosal sinus • Site of transition from medulla to spinal cord • Conveys CN XI and vertebral arteries into cranial vault Location of transverse sinuses Location of the confluens of the sinuses

Attachment for pharyngeal raphe Articulation with atlas Ethmoid • Forms roof of nasal cavity • Transmits filia olfactoria—CN I Perpendicular plate Forms superior aspect of nasal septum Nasal conchae (su- • Form superior aspect of lateral walls of perior and middle) nasal cavity • Act as turbinates for inspired air Crista galli Attachment for falx cerebri Sphenoid Lesser wing Forms superior border of superior orbital fissure (continued)

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Cranial bone summary (continued) Bone

Feature Greater wing Foramen ovale Foramen rotundum Foramen spinosum Sphenopalatine foramen Medial pterygoid plate Lateral pterygoid plate Optic canal Sphenoid sinus

Significance Forms inferior border of superior orbital fissure Conveys mandibular and lesser petrosal nerves Conveys maxillary nerve Conveys middle meningeal artery Conveys sphenopalatine artery and nasopalatine nerve to nasal cavity Possesses hamulus that tensor palati wraps around on way to soft palate Attachment for medial and lateral pterygoid muscles Conveys CN II and ophthalmic artery Paranasal air sinus that empties into sphenoethmoidal recess Sella turcica • Forms hypophyseal fossa—location of hypophysis • Anterior and posterior clinoid processes serve as attachments for diaphragma sella and border the sella turcica, the dorsum sellae forms the posterior border of the hypophyseal fossa Superior orbital • Space between lesser and greater wings fissure of the sphenoid • Conveys CN III, IV, and VI, the ophthalmic nerve, and superior ophthalmic vein Inferior orbital • Space between maxilla and greater wing fissure of sphenoid • Conveys infraorbital nerve Maxilla Zygomatic process Articulates with zygomatic bone to form anterior part of cheek Infraorbital foramen Conveys infraorbital neurovascular elements to face Alveolar processes Form sockets for maxillary teeth Infraorbital groove Conveys infraorbital neurovascular elements through orbit Incisive canal Conveys septal branches of sphenopalatine artery and branches of the nasopalatine nerve Palatine process Forms anterior 2⁄3 of bony palate Nasal surface Forms anterior aspect of lateral wall of nasal cavity Mandible Condylar process • Possesses a head and neck • Head articulates with temporal bone at temporomandibular joint (continued)

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Cranial bone summary (continued) Bone

Feature Coronoid process Mandibular foramen

Mental foramen Alveolar processes Mental spines (superior and inferior)

Mylohyoid line Ramus Angle Body Mandibular notch Mental protuberance Temporal Squamous part (2) Petrous part

Significance Distal attachment for temporalis • Point along interior of ramus where inferior alveolar neurovascular elements enter mandible • Lingula borders entrance, serves as attachment point for sphenomandibular ligament Conveys mental neurovascular elements to chin region Form sockets for mandibular teeth • Superior—proximal attachment for genioglossus • Inferior—proximal attachment for geniohyoid Proximal attachment for mylohyoid Vertical part between body (angle) and coronoid and condylar processes Bend between ramus and body • Horizontal part, forms base of mandible • Possesses alveolar processes Notch between condylar and coronoid processes Anterior prominence that forms the chin

Flat, lateral aspect; forms part of neurocranium • Thick, strong internal part • Houses vestibulocochlear apparatus Groove for superior Location of superior petrosal sinus petrosal sinus Groove for sigmoid Location of sigmoid sinus sinus Hiatus for greater Conveys greater petrosal nerve into cranial petrosal nerve vault Hiatus for lesser Conveys lesser petrosal nerve into cranial petrosal nerve vault Internal acoustic Conveys CN VII and VII from cranial vault meatus into petrous part of temporal bone External acoustic • Bony part of external ear meatus • Conveys sound to tympanic membrane Zygomatic process Articulates with temporal process of zygomatic bone to form zygomatic arch (continued)

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Cranial bone summary (continued) Bone

Feature Mandibular fossa

Articular tubercle

Styloid process

Mastoid process

Stylomastoid foramen Petrotympanic fissure Carotid canal

Tympanic canaliculus Jugular foramen

ZygoZygomaticofacial matic (2) and zygomaticotemporal foramen Temporal process

Significance Articulates with head of condylar process of mandible to form temporomandibular joint Bony prominence anterior to mandibular fossa that forms part of temporomandibular joint Proximal attachment for stylohyoid, stylopharyngeus, and styloglossus muscles and for stylohyoid and stylomandibular ligaments • Proximal attachment for posterior belly of digastric • Distal attachment for sternocleidomastoid Exit for CN VII motor fibers from the cranium Exit for chorda tympani from the cranium Canal conveying the internal carotid artery and its nerve plexus as they enter the cranium Conveys tympanic nerve into middle ear cavity Shared foramen between occipital and temporal bones that transmits CN IX, X, and XI, and internal jugular vein and inferior petrosal sinus Conveys sensory branches of zygomatic nerve to skin of cheek

Articulates with zygomatic process of temporal bone to form zygomatic arch Inferior Overall • Forms inferior aspect of lateral walls of nasal nasal cavity concha (2) • Acts as turbinate for inspired air Palatine Perpendicular plate Forms posterior part of lateral wall of nasal (2) cavity Horizontal plate Forms posterior 1⁄3 of hard palate Palatine foramina Convey greater and lesser palatine neuro(greater and lesser) vascular elements respectively Nasal (2) Overall Form bridge of nose Lacrimal Form part of medial wall of orbit (2) Vomer Forms posteroinferior aspect of nasal septum

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Clinical Significance Fractures of the mandible usually occur in pairs, frequently on opposite sides. The extraction of teeth leads to the resorption of alveolar bone. The mandible shrinks as a result, possibly leaving the mental foramen open and the mental nerves exposed to pain from dentures.

Additional Concept The cranial base is divided into three fossae for descriptive purposes: ■ ■ ■

anterior cranial fossa—anterior to lesser wings of the sphenoid middle cranial fossa—between lesser wings of the sphenoid and the petrous ridge of the temporal bone posterior cranial fossa—posterior to the petrous ridge of the temporal bone

Scalp The scalp consists of the skin and fascia covering the bones of the neurocranium.The first three layers form a single unit that move together. Layer

Description

Significance

Skin

Thin

Laden with hair follicles and sweat glands

Connective tissue

Thick

Dense, highly innervated

Aponeurosis

Connects frontal and occipi- Causes wrinkling of skin of tal bellies of occipitofrontalis forehead

Loose connective tissue

Loose, with potential spaces • Allows scalp to move freely • Potential spaces may allow for fluid accumulation

Pericranium

Dense connective tissue

Periosteum of neurocranium

Clinical Significance Trauma Scalp wounds that do not lacerate the epicranial aponeurosis tend not to gape, owing to its strength.

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Mnemonic Layers of the Scalp From superficial to deep, the layers of the scalp are: Skin Connective tissue Aponeurosis Loose connective tissue Pericranium

BRAIN Brain (Figure 7-1) The brain is divided into the cerebrum, cerebellum and brainstem. ■ ■

surface area is increased by gyri and sulci fissures are deep gyri

Structure Cerebrum

Description • Largest part of brain • Formed of 2 cerebral hemispheres and diencephalon • Cerebrum divided into lobes Diencephalon Located between cerebral hemispheres Cerebellum

Brainstem

Formed of 2 cerebellar hemispheres connected by a midline vermis Divided into midbrain, pons, and medulla

Significance Lobes: frontal, parietal, temporal, and occipital

Divided into thalamus, hypothalamus, epithalamus, and subthalamus Connected to pons of the brainstem by cerebellar peduncles • Midbrain—most rostral, gives rise to CN III and IV • Pons—gives rise to CN V, VI, VII, and VIII • Medulla—caudal-most, gives rise to CN IX, X, and XII

Clinical Significance Concussion and Contusion Concussion is a loss of consciousness after a head injury. Contusion results when the pia mater is stripped from the surface of the brain, allowing blood to enter the subarachnoid space.

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Cranial nerves (Figures 7-1, 7-3, and 7-7) Structure CN I CN II CN III

CN IV CN V

CN VI CN VII

CN VIII

CN IX

CN X

CN XI CN XII

Description Olfactory Optic Oculomotor

Significance Conveys sense of smell from nasal cavity Conveys visual information from retina • Motor to levator palpebrae superioris, superior, medial and inferior rectus, and inferior oblique • Parasympathetic to sphincter pupillae, ciliaris and superior tarsal muscles Motor to superior oblique Trochlear Three divisions: Trigeminal 1. Ophthalmic (V1)—sensory to upper 1⁄3 of face, cornea, and paranasal sinuses 2. Maxillary (V2)—sensory to middle 1⁄3 of face, upper teeth, maxillary sinuses, and palate 3. Mandibular (V3)—sensory to lower 1⁄3 of face, temporomandibular joint, anterior 2 ⁄3 of tongue, lower teeth, and motor to muscles of mastication, anterior belly of digastric, mylohyoid, tensor palati, and tensor tympani Motor to lateral rectus Abducens Facial • Motor to muscles of facial expression, stapedius, stylohyoid, and posterior belly of digastric • Parasympathetic to submandibular, sublingual and lacrimal glands, and to glands of the nasal and oral mucosa • Sensory to external acoustic meatus • Taste from anterior 2⁄3 of tongue Vestibulocochlear • Vestibular division—conveys balance and equilibrium information from inner ear • Cochlear division—conveys auditory information from inner ear Glossopharyngeal • Motor to stylopharyngeus • Parasympathetic to parotid gland • Sensory to parotid gland, pharynx, carotid body and sinus, and middle ear • Taste and sensation from posterior 1⁄3 of tongue Vagus • Motor to pharynx, palate (except tensor palati), and superior part of esophagus • Parasympathetic to thorax and abdomen to mid-transverse colon • Taste from palate and epiglottis • Sensory to external acoustic meatus Spinal accessory Motor to sternocleidomastoid and trapezius Hypoglossal Motor to muscles of tongue (except palatoglossus)

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CLINICAL ANATOMY FOR YOUR POCKET Inferior view

Eyeball Olfactory bulb Optic nerve (II) Olfactory tract (I)

Optic tract

Optic chiasm Lateral olfactory stria

Oculomotor nerve (III)

Trigeminal nerve (V): Ophthalmic nerve (V1)

Trochlear nerve (IV)

Maxillary nerve (V 2) Mandibular nerve (V3)

Abducens nerve (VI)

Trigeminal ganglion

Facial nerve (VII)

Pons Hypoglossal nerve (XII) Vagus nerve (X)

Vestibulocochlear nerve (VIII)

Accessory nerve (XI)

Glossopharyngeal nerve (IX) Medulla oblongata

Spinal cord

Ventral root of 1st spinal nerve

FIGURE 7-1. Cranial nerves, inferior view. (Asset provided by Anatomical Chart Company.)

Clinical Significance Trigeminal Nerve Trigeminal neuralgia (tic douloureux) is a sensory disorder of the trigeminal nerve of unknown cause. The result is excruciating pain over the face. Facial Nerve Injury to the facial nerve produces paralysis of the facial musculature (Bell’s palsy) on the ipsilateral side, causing the face to droop. Meninges The meninges support and protect the brain and cranial nerve roots. They form the subarachnoid space for cerebrospinal fluid. From superficial to deep, they are the: ■ ■ ■

dura mater arachnoid mater pia mater

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Meninges (continued) Structure Dura mater

Description Separates into 2 layers: periosteal and meningeal in several areas—forming dural sinuses and dural folds (meningeal layer)

Epidural space Subdural space

Potential space between cranium and dura mater • Potential space between the dura and arachnoid mater • Filled with a loosely adhered cell layer Middle meningeal layer

Arachnoid mater Arachnoid granulations

Significance • Tough, fibrous layer • Separated from cranium by epidural space • Dural sinuses are blood-filled channels between the periosteal and meningeal layers of dura • Meningeal dura is continuous with the dura mater of the spinal cord Site of epidural hematoma when trauma causes bleeding into space Site of subdural hematoma when trauma causes bleeding into space

Encloses the subarachnoid space

Evaginations of arachnoid Convey cerebrospinal fluid from through the dura into the subarachnoid space into the superior sagittal sinus where it superior sagittal sinus mixes with the venous blood Subarachnoid Between arachnoid mater • Contains cerebrospinal fluid, arachnoid trabeculae, and vessels and pia mater space • Irregular enlargements form cisterns Connective tissue strands Span the subarachnoid space Arachnoid that connect the trabeculae arachnoid and pia mater • Delicate inner layer in Invests spinal blood vessels and Pia mater the roots of the spinal nerves contact with the surface of the brain • Deep to the subarachnoid space

Clinical Significance Vascular and Nerve Supply The dura mater receives its arterial supply primarily from the middle meningeal artery; the veins of the dura follow the arterial branches.The dura mater has rich sensory innervation primarily from the branches of CN V. Headache Stretching of the dura mater is a common cause of headaches, as it is sensitive to pain.

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Dural folds Dural folds are formed where the dura mater separates into two layers: periosteal and meningeal. Structure Cerebral falx

Cerebellar falx Cerebellar tentorium

Feature • Infolding of meningeal layer of dura mater as it reflects away from periosteal layer • Supports and protects the brain • Possess dural sinuses in margins attached to periosteal layer of dura

Sellar diaphragm

Significance • Lies in longitudinal fissure of brain • Separates cerebral hemispheres • Superior sagittal sinus lies in attached edge, inferior sagittal sinus lies in inferior free edge; attaches to cerebellar tentorium • Separates cerebellar hemispheres • Occipital sinus lies in attached edge • Forms a roof over the cerebellum, separating it from the occipital lobe of the cerebrum • Divides cranial cavity into supra- and infratentorial compartments • Anteromedial deficiency—tentorial incisure, allows passage of the brainstem • Straight sinus lies in edge attached to cerebral falx • Forms roof over hypophysial fossa • Stretches between clinoid processes • Central deficiency—allows infundibulum to pass through • Cavernous and intercavernous sinuses lie at edges

Additional Concept Dural sinuses Dural sinuses are found along the attached edge of dural folds, most often between the periosteal and meningeal layers of dura mater. Sinus Superior sagittal

Feature • Endotheliallined venous channels in the attached edge of dural folds, between the layers of dura mater

Significance • Lies in superior, attached edge of cerebral falx • Receives CSF from arachnoid granulations • Lateral extensions—lateral lacunae also receive CSF • Conveys contents to confluens of the sinuses (continued)

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Dural sinuses (continued) Sinus Inferior sagittal Straight

Feature • Receive cerebral veins and convey venous blood and cerebrospinal fluid (CSF) to the internal jugular vein

Significance • Lies in the inferior, free edge of cerebral falx • Conveys contents to straight sinus • Formed by union of inferior sagittal sinus and great cerebral vein • Found in the attachment between the cerebral falx and cerebellar tentorium

Confluence

• Receives blood from straight and superior sagittal sinuses, conveys blood to transverse sinuses • Located near the internal occipital protuberance

Transverse

Pass laterally from confluence of sinus, convey blood to sigmoid sinuses

Sigmoid

• Continuation of transverse sinuses • Continuous with internal jugular vein at jugular foramen

Petrosal (superior and inferior)

• Both drain cavernous sinus • Superior—located in anterolateral attached edge of cerebellar tentorium, drains to junction of transverse and sigmoid sinuses • Inferior—drains into internal jugular vein

Occipital

• Located in attached edge of cerebellar tentorium • Drains blood to the confluence of the sinuses

Cavernous

• Located on either side of the sella turcica, associated with the sellar diaphragm • Communicates with ophthalmic veins and pterygoid plexus • Drains posteriorly via petrosal veins • Walls of sinus contain V1, V2, CN III and IV, sinus itself contains internal carotid artery and CN VI • Right and left sinuses connected anteriorly and posteriorly via intercavernous sinuses

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Clinical Significance Cavernous Sinus Fractures of the cranial base may tear the internal carotid artery as it passes through the cavernous sinus, first causing compression of CN VI and subsequently the structures in the wall of the sinus. Ventricular system of the brain The ventricular system of the brain is both the source and pathway for the flow of cerebrospinal fluid (CSF). CSF acts as a buffer, waste depository, and shock absorber for the brain. Structure Lateral (1st and 2nd) ventricles 3rd ventricle

Description Significance Cerebrospinal (CSF) flows • CSF is created by specialized through interventricular tufts of pia mater—choroid foramina into 3rd ventricle plexus, located in each of the 4 ventricles CSF flows through cere• CSF is absorbed into the venous bral aqueduct into 4th system through arachnoid ventricle granulations—evaginations of arachnoid mater into the superior sagittal sinus 4th ventricle CSF flows through a median and 2 lateral apertures to enter subarachnoid space Subarachnoid CSF-filled space between • Surrounds brain • Distended in areas to form space the arachnoid and pia subarachnoid cisterns (e.g., mater cerebellomedullary cistern (cisterna magna)—between the medulla and cerebellum

Clinical Significance CSF may be obtained for diagnostic purposes by a lumbar puncture, or in the case of an infant from the cerebellomedullary cistern via a cistern puncture. Excessive cerebrospinal fluid dilates the brain ventricles (hydrocephalus) and may cause thinning of the cerebral cortex and separation of the bones of the calvaria in infants. Vasculature of the brain (Figure 7-2) Vessel Arteries Internal carotid (2)

Origin/Termination

Supplies/Gives Rise To

Origin: common carotid; • Give rise to ophthalmic, enter skull through carotid anterior, and middle cerebrals (continued)

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Vasculature of the brain (continued) Vessel

Vertebral (2)

Origin/Termination canal, and pass through cavernous sinus Origin: subclavian; pass through transverse foramina of cervical vertebrae and foramen magnum to enter skull Internal carotid

Supplies/Gives Rise To • Primary supply to brain

• Give rise to basilar, posterior inferior cerebellar, and anterior spinal arteries • Supply meninges, brain stem, and cerebellum Supply medial aspect of cerebral Anterior hemispheres cerebral Supply lateral aspect of cerebral Middle hemispheres cerebral Supply inferior aspect of cerebral Posterior Basilar hemispheres cerebral • Gives rise to anterior inferior Basilar Vertebral cerebellar, labyrinthine, pontine, superior cerebellar, and posterior cerebral arteries • Supply brainstem, cerebellum, and cerebrum Forms part of cerebral arterial Anterior Anterior cerebral circle communicating • Forms part of cerebral arterial Posterior Posterior cerebral circle communicating • Supply cerebral peduncle, internal capsule, and thalamus Venous drainage is indirect, draining first to the dural sinuses, then to true veins.

Additional Concept The cerebral arterial circle (of Willis), is located at the base of the brain and is the anastomosis between the vertebrobasilar and internal carotid systems. It is formed by the posterior cerebral, posterior communicating, internal carotid, anterior cerebral, and anterior communicating arteries.

Clinical Significance Stroke An artery supplying the brain can result in a stroke, cerebrovascular accident (CVA) and be evidenced by impaired neurologic function. Occlusion can occur by an embolus (clot) blocking arterial flow. Emboli can originate locally or at some distance (the heart).

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CLINICAL ANATOMY FOR YOUR POCKET Anterior communicating artery

Anterior cerebral artery

Optic chiasm Infundibulum Circle of Willis Internal carotid artery Middle cerebral artery Posterior communicating artery

CNII

CNIII Superior cerebellar artery Pontine arteries Anterior inferior cerebellar artery

Posterior cerebral artery CNVI Basilar artery

Labyrinthine (internal auditory) artery Posterior inferior cerebellar artery Posterior spinal artery

Vertebral artery Anterior spinal artery

FIGURE 7-2. Circle of Willis. (From Dudek RW, Louis TM. HighYield Gross Anatomy. 3rd ed. Baltimore: Lippincott Williams & Wilkins; 2008:270.)

FACE Muscles of the face (Figure 7-3) Muscle Occipitofrontalis— frontal and occipital bellies

Proximal Attachment Frontal— epicranial aponeurosis Occipital— superior nuchal line

Distal Attachment Innervation Frontal—skin Facial of forehead Occipital— epicranial aponeurosis

Main Actions Elevates eyebrows, wrinkles skin of forehead

(continued)

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Muscles of the face (continued) Muscle

Proximal Attachment

Distal Attachment

Innervation

Main Actions

Orbicularis Margin of orbit, oculi medial palpebral ligament, and lacrimal bone

Skin around margin of orbit and tarsal plates

Closes palpebral fissure

Corrugator Frontal bone supercilii

Skin superior to orbit

Wrinkles skin above nose by drawing eyebrows medially

Procerus

Nasal bone and Skin of lateral nasal forehead cartilage

Wrinkles skin of nose

Nasalis

Maxilla, nasal Alar cartilage, bone, and lateral skin of forenasal cartilage head

Flares nostrils, wrinkles skin of nose

Levator Maxilla labii superioris alaeque nasii

Alar cartilage

Flares nostrils

Orbicularis Maxilla and oris mandible; skin around mouth

Lips

Closes mouth, protrudes lips

Levator Maxilla labii superioris

Skin of upper lip

Opens mouth; elevates upper lip

Depressor Platysma, body labii inferi- of mandible oris

Skin of lower lip

Opens mouth; depresses angle of mouth

Buccinator Pterygomandi- Angle of bular raphe; mouth alveolar processes of maxilla and mandible

Presses cheek against teeth to keep food out of oral vestibule when chewing

Zygomati- Zygomatic bone cus major

Opens mouth; elevates angle of mouth

Zygomaticus minor

Skin of upper lip

Levator Infraorbital anguli oris maxilla

Angle of mouth (continued)

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Muscles of the face (continued) Proximal Attachment

Muscle

Distal Attachment

Innervation

Main Actions

Depressor Base of mandible anguli oris

Opens mouth; depresses angle of mouth

Risorius

Fascia of parotid gland and skin of cheek

Opens mouth

Platysma

Skin of supraMandible, skin clavicular region of cheek and mouth, orbicularis oris

Depresses mandible, tenses skin of neck

Mentalis

Body of mandible

Elevates skin of chin; elevates and protrudes lower lip

Skin of chin

Supratrochlear nerve

Procerus

Levator labii superioris alaeque nasii

Supraorbital nerve Zygomaticofacial nerve

Levator labii superioris Levator anguli oris

Infraorbital nerve

Masseter

Parotid duct

Mentalis

Depressor anguli oris Mental nerve

FIGURE 7-3. Anterior view of the face showing the cutaneous branches of the trigeminal nerve, muscles of facial expression, and eyelid (Image from Grant’s Atlas of Anatomy.)

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Vasculature of the face (Figure 7-4) Vessel Arteries Facial Labial (superior and inferior) Lateral nasal Angular Superficial temporal Transverse facial

Origin

Supplies/Gives Rise To

External carotid Face Facial Lips and nose Nose Nose and inferior eyelid External carotid Lateral aspect of face and temporal region Superficial Face and parotid region temporal External carotid Back of head Auricle and area posterior to auricle Inferior alveolar Chin Ophthalmic Forehead and scalp

Occipital Posterior auricular Mental Supraorbital Supratrochlear Venous drainage parallels arterial supply.

Lymphatics of the Head Lymphatic vessels from the head drain into deep cervical lymph nodes, which drain to the jugular lymphatic trunk. Collections of lymphatic tissue—tonsils, are found near the opening of the auditory tube—tubal tonsils, between the anterior and posterior pillars of the oral cavity—palatine tonsils, on the posterior aspect of the tongue—lingual tonsils and on the posterior aspect of the nasopharynx—pharyngeal tonsils. Together these accumulations of lymphatic tissue form Waldeyer’s Ring. Nerves of the face (Figure 7-3) Nerve Origin Structures Innervated Sensory Branches of the Ophthalmic Nerve Supraorbital Frontal • Anterolateral scalp and forehead • Frontal sinus • Upper eyelid Supratrochlear • Anteromedial scalp and forehead • Upper eyelid (continued)

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Nerves of the face (continued) Nerve Infratrochlear

Origin Nasociliary

Lacrimal

Ophthalmic

External nasal

Structures Innervated • Medial aspect of both eyelids • Lacrimal sac and caruncle • Lateral aspect of nose • Conveys parasympathetics to the lacrimal gland • Conjunctiva and skin of upper eyelid Majority of nose

Anterior ethmoidal— branch of nasociliary Branches of the Maxillary Nerve Infraorbital Maxillary • Cheek, upper lip, lower eyelid • Maxillary sinus and teeth Zygomaticofacial Zygomatic Cheek Zygomaticotemporal Anterior aspect of temporal region Branches of Mandibular Nerve Buccal Mandibular • Cheek—skin and mucosa • Buccal gingivae Mental Inferior • Chin alveolar • Mucosa of lower lip Auriculotemporal Mandibular—2 • Posterior aspect of temporal region roots encircle • Anterior parts of ear, external auditory middle meninmeatus and tympanic membrane geal artery • Conveys secretomotor fibers to the parotid gland from the otic ganglion Branches from Cervical Spinal Nerves Great auricular Anterior rami— • Angle of mandible C2 and C3 • Lobe of ear • Parotid sheath Lesser occipital Scalp posterior to ear Greater occipital Posterior Scalp of occipital region ramus—C2 3rd occipital Posterior Scalp of occipital and suboccipital ramus—C3 regions Motor Branches of the Facial (CN VII) Muscles of facial expression facial nerve— temporal, zygomatic, buccal, mandibular, and cervical Mandibular (V3) Trigeminal Muscles of mastication

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Additional Concept Trigeminal Nerve Branches of the trigeminal nerve (CN V) provide most sensory innervation of the face. The three divisions of the trigeminal nerve are the ophthalmic (V1), maxillary (V2), and mandibular (V3) nerves.

TEMPORAL REGION Temporal region structure Structure

Description

Significance

Temporal fossa

• Bounded superiorly and posteriorly by superior and inferior temporal lines of the parietal bones • Floor formed by 4 bones that make up the pterion

• Proximal attachment of temporalis • 4 bones forming pterion: frontal, parietal, temporal, and greater wing of sphenoid

Infratemporal fossa

• Bounded laterally by the zygomatic arch and mandible • Medial border: lateral pterygoid plate • Found posterior to the maxilla

Contains: • Part of temporalis • Medial and lateral pterygoid muscles • Pterygoid plexus of veins • Maxillary artery • Branches of mandibular nerve

Additional Concept The temporal region includes the temporal—superior to the zygomatic arch and infratemporal fossae—inferior to the zygomatic arch.

Clinical Significance Mandibular Nerve A needle is passed through the mandibular notch of the mandible into the infratemporal fossa to anesthetize the mandibular nerve as it emerges from the cranial cavity.

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Vasculature of the temporal region Vessel Arteries

Origin

Maxillary

External carotid Supplies structures of the temporal region

Deep auricular

Maxillary— 1st part

Anterior tympanic

Supplies/Gives Rise To

Supplies external auditory meatus Supplies tympanic membrane

Middle meningeal

Supplies dura mater

Inferior alveolar

• Supplies mandible, floor of mouth, gingivae, and mandibular teeth • Gives rise to mental—supplies chin

Deep temporal Muscular (masseteric, buccal and pterygoid branches) Posterior superior alveolar

Maxillary— 2nd part

Maxillary— 3rd part

Supplies temporalis Supply masseter, buccinator and cheek, and the medial and lateral pterygoids

Supplies posterior maxillary teeth and gingivae

Infraorbital

• Supplies lower eyelid, lacrimal sac, upper lip, and infraorbital region of face • Gives rise to anterior superior alveolar—supplies anterior maxillary teeth and gingivae

Descending palatine

Supplies palate and gingivae

Pharyngeal

Supplies superior aspect of pharynx

Sphenopalatine

Supplies lateral nasal wall and septum Drains

Vessel Veins

Termination

Pterygoid venous plexus

Facial and Structures in the infratemporal fossa maxillary veins

Venous drainage generally parallels arterial supply in the temporal region.

Additional Concept The maxillary artery is divided into 3 parts by its relation to the lateral pterygoid muscle.

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Nerves of the temporal region Nerve Mandibular (V3)

Origin Trigeminal

Structures Innervated • Sensory to structures in the temporal region • Branches convey parasympathetic fibers • Motor to muscles of mastication Buccal Mandibular • Cheek—skin and mucosa • Buccal gingivae Auriculotemporal • Posterior aspect of temporal region • Anterior parts of ear, external auditory meatus, and tympanic membrane • Conveys secretomotor fibers to the parotid gland from the otic ganglion Inferior alveolar • Forms inferior dental plexus that innervates mandibular teeth • Emerges from mental foramen as mental nerve Lingual • Anterior 2⁄3 of tongue and lingual gingivae • Conveys secretomotor fibers to the submandibular ganglion and submandibular and sublingual glands • Conveys special sense of taste from anterior 2⁄3 of tongue to chorda tympani Nerve to mylohyoid Inferior alveolar Mylohyoid Chorda tympani Facial • Receives taste fibers from anterior 2 ⁄3 of tongue from lingual nerve • Conveys presynaptic parasympathetics from CN VII to lingual nerve Otic ganglion Innervated by Postsynaptic fibers ride on the auriculoinferior saliva- temporal nerve to innervate the parotid tory nucleus gland

PTERYGOPALATINE FOSSA Pterygopalatine fossa The pterygopalatine fossa is a small, inverted rain drop shaped fossa, which is positioned for access to multiple areas of the head for distribution of neurovascular elements. Structure Overall

Description Borders: • Superior—greater wing of sphenoid

Significance Openings and communications: • Superior/anterior—orbit through inferior orbital fissure (continued)

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Pterygopalatine fossa (continued) Structure

Description • Anterior—maxilla • Inferior—pyramidal process of palatine • Medial—perpendicular plate of palatine • Lateral—continuous with infratemporal fossa

Contents

Maxillary nerve

Pterygopalatine ganglion

Maxillary artery

Significance • Inferior/posterior—middle cranial fossa through foramen rotundum • Medial—nasal cavity through sphenopalatine foramen • Lateral—infratemporal fossa through pterygomaxillary fissure • Enters fossa via foramen rotundum • Gives off zygomatic nerve in fossa—conveys postsynaptic parasympathetic fibers from pterygopalatine ganglion to lacrimal nerve—to lacrimal gland • Gives off pterygopalatine nerves that suspend pterygopalatine ganglion—convey general sense through ganglion to branches of V2—supply nasal and oral cavities • Leaves fossa via infraorbital fissure and changes name to infraorbital nerve • Parasympathetic ganglion • Presynaptic innervation is from superior salivatory nucleus via the greater petrosal nerve— a branch of CN VII • Greater petrosal joins the deep petrosal—sympathetic, to form the nerve of the pterygoid canal • Autonomics leave ganglion to innervate lacrimal, nasal, and oral cavity glands • Enters fossa via pterygomaxillary fissure • Gives rise to following branches in fossa: 1. Posterior superior alveolar 2. Descending palatine 3. Sphenopalatine 4. Infraorbital—gives rise to anterior superior alveolar in infraorbital canal

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ORAL REGION Oral region (Figure 7-4) The oral region includes the oral cavity, which extends to the palate superiorly and the palatopharyngeal fold posteriorly, tongue, teeth, and gingivae (gums). The oral cavity receives ingested substances, begins digestion, and forms a bolus that can be swallowed. Structure Description Oral vestibule Space between the teeth and gingivae and the lips

Oral cavity proper

Gingivae (gums)

Teeth

Significance • Oral fissure—space between upper and lower lips, size varies by orbicularis oris and labial muscles • Lips—muscular folds surrounding oral fissure; upper lip sensory by V2, lower by V3; philtrum—vertical groove in upper lip • Cheeks—contain buccinator muscles that function to keep food out of oral vestibule between the occlusal surfaces of teeth • Continuous posteriorly with the Space contained within oropharynx superior and inferior dental • Space occupied by the tongue arches—formed of the maxillary and mandibular alveolar processes that contain the teeth • Mandibular gingivae innervated • Mucous membrane by buccal and lingual nerves covered fibrous tissue • Maxillary gingivae innervated • Adherent to alveolar by greater palatine, processes and necks of nasopalatine, and superior teeth alveolar nerves—anterior, middle, and posterior • Used in mastication • Hard, enamel-covered • 20 deciduous teeth in children • Set in alveolar • Maxillary teeth innervated by processes of maxilla superior dental plexus, formed and mandible by branches of V2 • Possess crown, root, and neck • Mandibular teeth innervated by • 32 total in adult: 6 inferior dental plexus, formed molars, 4 premolars, 2 by branches of V3 canine, and 4 incisors in each dental arch (continued)

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Oral region (continued) Structure Tongue

Description • Muscular organ, mostly contained within oral cavity proper • Divided into right and left halves by midline groove • Possesses: • Root—posterior 1⁄3 • Body—anterior 2⁄3 • Apex—tip • Dorsum—site of lingual papillae: vallate, foliate, filiform and fungiform • Inferior surface—has lingual frenulum

Palate

• Forms roof of oral cavity and floor of nasal cavities • Hard palate—bony anterior portion, formed by palatine processes of maxilla and horizontal plates of palatine bones • Soft palate—moveable posterior portion of palate; anterior part— composed of palatine aponeurosis, posterior part—muscular • Articular disk with anterior and • Synovial joint posterior bands divides the joint cavity into 2 separate compartments

Temporomandibular joint

Significance • Functions in mastication, deglutition, articulation and taste • V-shaped groove on dorsum— terminal groove divides tongue into anterior 2⁄3 and posterior 1⁄3 parts, center of groove possesses small pit— foramen cecum that was the opening of the thyroglossal duct in the embryo • Vallate, foliate, and fungiform papillae have taste buds • Lingual frenulum connects tongue to floor of mouth • Innervation: • Motor—hypoglossal to all muscles except palatoglossus: pharyngeal plexus • Sensory to anterior 2⁄3: general sense—lingual, taste—chorda tympani • Posterior 1⁄3: general sense and taste— glossopharyngeal • Blood supply: lingual artery, veins parallel arteries • Hard palate has 3 foramina: 1. Incisive fossa: conveys nasopalatine nerve to anterior aspect of hard palate 2. Greater palatine foramen: conveys greater palatine vessels and nerves to posterior aspect of hard palate 3. Lesser palatine foramen: conveys lesser palatine vessels and nerves to soft palate • Soft palate: uvula assists in closing oropharynx from nasopharynx during swallowing

(continued)

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Oral region (continued) Structure

Description Significance • Joint supported by a strong • Between head of lateral ligament—a mandible with thickening of the joint capsule mandibular fossa and and by 2 extrinsic ligaments: articular tubercle of the (1) stylomandibular temporal bone ligament and (2) sphenomandibular ligament • Movements: elevation, depression, protrusion, retrusion, and side-to-side grinding movements

Clinical Significance Temporomandibular Joint The temporomandibular joint may become arthritic, leading to problems with dental occlusion and joint clicking (crepitus).

Frontal sinus Nasal conchae

Hypophysial fossa Sphenoid sinus Pharyngeal tonsil

Hard palate

Auditory tube Palatoglossal arch

Genioglossus

Palatine tonsil

Geniohyoid

Palatopharyngeal arch

Mandible

Epiglottis Vestibular fold Ventricle Vocal fold

FIGURE 7-4. Nasopharynx, oropharynx, and laryngopharynx. (From Moore KL, Agur AMR. Essential Clinical Anatomy. 3rd ed. Baltimore: Lippincott Williams & Wilkins; 2007:621.)

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Deep Lingual Veins The deep lingual veins on the inferior surface of the tongue provide a rapid entry for drugs, such as nitroglycerin for treatment of angina pectoris. Tongue Tied An overlarge lingual frenulum (tongue tie) interferes with tongue movement and speech. Frenectomy may be performed to free the tongue. Salivary glands There are three pairs of salivary glands: ■ ■ ■

parotid submandibular sublingual

All glands received secretomotor fibers from the parasympathetic nervous system. They function to produce saliva, which binds ingested foot into a bolus and begin the digestive process. Gland Parotid

Description • Possesses tough fascial sheath—parotid sheath • Located anteroinferior to external auditory meatus • Parotid duct passes anteriorly to convey secretions into the oral cavity near the 2nd maxillary molar

Submandibular • Located deep to body of mandible • Submandibular duct passes anteriorly to convey secretions into the oral cavity on the surface of sublingual papilla— located on either side of the lingual frenulum • Located between the Sublingual mandible and genioglossus muscle in floor of mouth • Convey secretions into oral cavity via multiple sublingual ducts

Significance • Parasympathetic innervation from cells in otic ganglion reach target via auriculotemporal nerve • Sympathetic innervation from carotid plexus inhibit secretion • Sensory innervation via auriculotemporal nerve • Parasympathetic innervation from cells in the submandibular ganglion reach target via the lingual nerve • Sympathetic innervation from carotid plexus inhibit secretion

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Clinical Significance Sialography In a sialography, contrast is injected into the submandibular duct to reveal the duct and some of the secretory units of the gland. Muscles of mastication Proximal Muscle Attachment Temporalis Temporal fossa

Masseter

Zygomatic arch

Medial pterygoid

Medial surface of lateral pterygoid plate

Lateral pterygoid

Lateral surface of lateral pterygoid plate

Distal Main Attachment Innervation Actions Mandibular Elevate and Coronoid retract mandible process of mandible Elevate Lateral aspect mandible of angle and ramus of mandible Elevate Medial aspect mandible, of angle and produces sideramus of to-side grinding mandible motion Protrudes Disk of mandible, sidetemporomandi to-side grinding bular joint and motion condyloid process of mandible

Additional Concept The masseter and medial pterygoid essentially form a sling attached to the angle of the mandible that elevates the mandible. Extrinsic muscles of the tongue (Figure 7-4) Extrinsic Proximal Muscle Attachment Genioglossus Superior mental spine of mandible Hyoglossus

Hyoid bone

Distal Attachment Dorsum of tongue and hyoid

Main Innervation Actions Hypoglossal Depresses, protrudes and moves tongue from side to side Depresses and Lateral aspect retrudes tongue of tongue (continued)

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Muscles of the tongue (continued) Extrinsic Muscle Styloglossus

Proximal Distal Attachment Attachment Styloid process

Dorsum of Palatoglossus Palatine aponeurosis tongue

Main Innervation Actions Retrudes tongue, elevates sides Pharyngeal Draws soft plexus palate and tongue together

Additional Concept The intrinsic muscles of the tongue—superior and inferior longitudinal, transverse, and vertical—have no bony attachments and function to alter the shape of the tongue; they are all innervated by the hypoglossal nerve. The extrinsic muscles of the tongue alter the position of the tongue. Muscles of the palate Muscle Tensor palati

Proximal Attachment Scaphoid fossa between medial and lateral pterygoid plates

Levator palati

Cartilage of auditory tube

Distal Attachment Palatine aponeurosis

Palatoglos- Palatine aponeurosis sus

Tongue

Palatopharyngeus

Pharynx

Musculus uvulae

Uvula

Main Innervation Actions Mandibular • Tenses soft (V3) palate and opens auditory tube during swallowing • Changes direction of pull by wrapping around hamulus of medial pterygoid plate Pharyngeal Elevates soft palate plexus Draws soft palate and tongue together Tenses soft palate, elevates pharynx Elevates uvula

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Additional Concept The palatoglossus and palatopharyngeus are covered by mucosa and are often referred to as the anterior and posterior pillars in dentistry. Between them lies the tonsillar fossa for the palatine tonsil.

NOSE AND EAR Nose (Figure 7-4) The nasal apparatus includes the external nose, nasal cavities, and paranasal air sinuses. It functions in olfaction, respiration, filtration and humidification of inspired air. Structure Description External nose • Composed of a dorsum (bridge) and apex (tip) • Nares (nostrils)—are bounded laterally by the alae of the nose and medially separated by the nasal septum; open into the nasal cavities • Possesses bony and cartilaginous parts Nasal cavities • Mucosal-lined cavities separated by nasal septum • Superior 1⁄3 is olfactory—contains olfactory receptor cells • Inferior 2⁄3 is respiratory • Arterial supply: sphenopalatine, ethmoidal (anterior and posterior), greater palatine, superior labial, and branches of the facial arteries • Veins parallel the arteries • Sensory innervation is via nasopalatine, greater palatine, and anterior ethmoidal nerves

Significance • Bony skeleton: • Nasal bones • Frontal bone—nasal part and nasal spine • Nasal septum • Maxillae—frontal process • Cartilaginous skeleton: • Lateral cartilages (2) • Alar cartilages (2) • Septal cartilage • Nasal septum composed of: perpendicular plate of ethmoid, vomer, and septal cartilage • Lateral walls possess superior, middle, and inferior nasal conchae—act as turbinates • Spaces inferior to conchae— superior, middle, and inferior meatuses • Space superior to superior concha is sphenoethmoidal recess • The nasal cavities are continuous with the nasopharynx posteriorly at the choanae

(continued)

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Nose (continued) Structure Paranasal sinuses

Description Extensions of the nasal cavity into the surrounding bones: • Frontal • Ethmoidal—divided into anterior, middle, and posterior air cells • Sphenoidal • Maxillary

Significance Function as resonant chambers for the voice and in lightening the skull

Clinical Significance Bloody Nose Kiesselbach’s area is an area on the anterior aspect of the nasal septum where all five arteries supplying the nasal cavity anastomose. It is an area from which may come profuse bleeding. Deviated Septum The nasal septum is usually deviated to one side or the other, either naturally or as a result of trauma. Deviation can be corrected if it is severe and interferes with breathing or exacerbates snoring.

Additional Concept The meatuses and sphenoethmoidal recess are spaces that communicate with sinuses where structures empty into the nasal cavity: ■ ■ ■

■

sphenoethmoidal recess: sphenoid sinus superior meatus: posterior ethmoid air cells middle meatus: middle ethmoid air cells onto the ethmoid bulla—an expanded ethmoid air cell in the meatus; anterior ethmoid air cell and maxillary sinus into the semilunar hiatus—a depression surrounding the ethmoid bulla; frontal sinus via frontonasal duct into the infundibulum— leads to the semilunar hiatus inferior meatus: nasolacrimal duct

Ear (Figure 7-5) The ear is divided into external, middle, and inner parts. The external and middle ear transfer sound to the inner ear.

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The inner ear contains the organs of hearing and equilibrium. Part Description External • Composed of auricle and external auditory meatus—bony cartilaginous S-shaped tube • Innervated primarily by auriculotemporal and great auricular nerves • Arterial supply: posterior auricular and superficial temporal arteries • Veins parallel arteries Middle • Air-filled chamber between the tympanic membrane and inner ear • Connected to nasopharynx by auditory tube and mastoid air cells through aditus • Contains malleus, incus, and stapes • Stapedius and tensor tympani connect to stapes and malleus, respectively • Chorda tympani travels through middle ear cavity • Spiraling series of periInner lymph-containing channels through the petrous part of temporal bone— bony labyrinth contains endolymph-filled membranous labyrinth • Organs of membranous labyrinth: saccule, utricle, semicircular canals (3), and cochlea • Cochlea is innervated by the cochlear division of CN VIII • Saccule, utricle, and semicircular canals are innervated by the vestibular division of CN VIII

Significance • Auricle funnels sound into external auditory meatus • External auditory meatus: • Ends at tympanic membrane (eardrum)—border between external and middle ear • Filled with hairs and cerumen (wax)

• Auditory tube equalizes middle ear pressure with atmospheric pressure for optimal hearing • Tympanic membrane vibrations are transferred along the malleus, incus and stapes—the movement of the stapes in the oval window transfers the vibration to the inner ear • Stapedius and tensor tympani dampen sound—innervation: stapedius—CN VII, tensor tympani— CN V

• Saccule and utricle: located in vestibule of bony labyrinth; contain macula—receptor organ that responds to changes in head position • Semicircular canals: 3 on each side, contain crista ampullari— receptor organs that respond to head acceleration • Cochlea: transduces vibrations of stapes in oval window to excitation of CN VIII using organ of Corti— receptor organ of membranous labyrinth for hearing

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Tympanic membrane Stapes

Semicircular canals Vestibular nerve

Auricle

Cochlear nerve Vestibulocochlear nerve

External acoustic meatus

Internal acoustic meatus Cochlea

Opening of external acoustic meatus

Auriculotemporal nerve

Anterior view

Parotid gland Pharyngotympanic tube

FIGURE 7-5. Anatomy of ear. (From Dudek RW, Louis TM. High-Yield Gross Anatomy. 3rd ed. Baltimore: Lippincott Williams & Wilkins; 2008:302.)

Clinical Significance Ear Infection Otitis media, an infection of the middle ear cavity, can be secondary to an upper respiratory tract infection. The bulging, red tympanic membrane may perforate as a result of pressure from infection or trauma.

ORBIT Orbit structure (Figures 7-3 and 7-6) The orbits are a pair of bony, pyramidal-shaped cavities in the face that contain: ■ ■ ■ ■

eye extraocular muscles lacrimal apparatus neurovascular elements

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Orbit structure (continued) Structure Orbit

Palpebrae (eyelids)

Eye

Description Bony walls: • Superior—orbital part of frontal and lesser wing of sphenoid • Inferior—maxilla and zygomatic and palatine • Medial—ethmoid and frontal, lacrimal and sphenoid • Lateral—frontal process of zygomatic and greater wing of sphenoid Apex: optic canal Base: orbital margin • Outer surface—thin skin • Inner surface—palpebral conjunctiva • Middle—orbicularis oculi and tarsal plates: superior and inferior and tarsal glands • Medial and lateral palpebral ligaments attach tarsal plates to orbit • Eyelashes and ciliary glands • Lacrimal puncta open on summit of lacrimal papilla on the upper and lower eyelids • Orbital septum—an extension of periosteum that connects to the tarsal plates • 3 layers of eyeball: 1. Outer—fibrous: sclera and cornea 2. Middle—vascular: choroid, ciliary body composed of ciliaris and ciliary processes and iris that contains dilator pupillae and sphincter pupillae

Significance • Superior wall contains fossa for lacrimal gland • Medial wall contains lacrimal groove and fossa for lacrimal sac • Inferior wall is separated from lateral by inferior orbital fissure, which conveys the continuation of the maxillary nerve • Optic canal conveys the optic nerve (CN II)

• Overall: the eyelids protect and moisten the eye, sweeping lacrimal secretions inferomedially toward medial canthus of eye • Tarsal plates strengthen eyelids and act as skeleton; the superior tarsal muscle attaches to superior tarsal plate • Tarsal glands associated with tarsal plates secrete lipids to prevent eyelids from sticking together and leaking of lacrimal fluid • Palpebral ligaments provide attachment for orbicularis oculi • Orbital septum helps stop the spread of infection and maintains the orbital fat in place

• Outer layer: sclera—white, opaque posterior 5⁄6, fibrous skeleton of eye; cornea— anterior 1⁄6, transparent, avascular part of refractive media • Middle layer: choroid—contains blood vessels; ciliary body—contraction of ciliaris by CN III parasympathetics produces accommodation, ciliary processes secrete (continued)

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Orbit structure (continued) Structure

Lacrimal apparatus

Description Significance aqueous humor and via 3. Inner—retina: suspensory ligaments hold the divided into outer lens; iris—continually varies pigmented layer and in size to alter size of pupil, inner neural layer dilator under sympathetic con• Spaces within eyeball trol, and sphincter under divided into 3 parts: parasympathetic control (CN III) 1. Anterior chamber— between cornea and • Inner layer: retina inner neural layer contains photoreceptors iris and the ganglion cells that form 2. Posterior chamber— CN II, ends anteriorly at ora between iris and lens serrata; area of highest visual 3. Vitreous body—fills acuity—macula lutea the cenarea posterior to lens ter of which has a small pit— • Lens—flexible avascular fovea centralis, located at the part of refractive media center of the visual axis; optic of eye; surrounded by disk is a blind spot medial to lens capsule that is macula lutea where CN II tensed by suspensory leaves the eye and the central ligaments artery of the retina enters • Lacrimal glands—produce • Lacrimal glands— lacrimal secretions (tears); located in the fossa for secretomotor from facial nerve the lacrimal gland parasympathetics, sympathet• Lacrimal ducts— ics inhibit production empty into superior • Lacrimal ducts—convey fornix lacrimal secretions to conjunc• Lacrimal canaliculi tival sac convey tears to the lacrimal sac via capil- • Lacrimal sac is the dilated proximal end of the lary action nasolacrimal duct that conveys lacrimal secretions to the inferior nasal meatus

Additional Concept Conjunctiva The conjunctiva is a mucous membrane that is loosely adherent to the sclera, known as bulbar conjunctiva, where it is invested with blood vessels and on the inner surface of the eyelids as palpebral conjunctiva. At the medial canthus of the eye—the junction of the upper and lower eyelids on the medial side, the remnant of a human nictitating membrane is evident as a semilunar fold of conjunctiva. The semilunar fold lines the lacrimal lake, at the center of which is an elevation, the lacrimal caruncle that functions

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Branches of retinal vessels Macula

Optic disc

FIGURE 7-6. Retina. (From Dudek RW, Louis TM. High-Yield Gross Anatomy. 3rd ed. Baltimore: Lippincott Williams & Wilkins; 2008:298.)

to push the lacrimal secretions to the edge of the lake so that they can be removed by lacrimal canaliculi. The lines of reflection between bulbar and palpebral conjunctiva are the superior and inferior fornices. The conjunctiva line a sac, the conjunctival sac the opening of which is the palpebral fissure—the space between the upper and lower eyelids. It is into this sac that contact lenses are inserted and eyedrops deposited and into the superior fornix of the sac where lacrimal secretions are emptied via excretory ducts.

Clinical Significance Blowout Fracture A blow to the orbit is most likely to fracture the relatively thin inferior and medial walls, leading to a blowout fracture with the stronger bony margin intact. Exophthalmos Tumors within the orbit or deposition of retrobulbar fat (as in Grave’s disease) produce exophthalmos or protrusion of the eye.

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Conjunctivitis The conjunctiva is colorless except when its vessels are dilated (bloodshot eyes) or inflamed from infection (conjunctivitis, or pinkeye). Extraocular muscles (Figures 7-7 and 7-8) Proximal Muscle Attachment Lesser wing of Levator palpebrae sphenoid superioris

Superior rectus

Common tendinous ring

Distal Attachment Superior tarsal plate, skin of upper eyelid

Innervation Oculomotor and sympathetics— superior tarsal muscle Anterior hemi- Oculomotor sphere of sclera

Inferior rectus

Medial rectus Lateral rectus Superior oblique

Inferior oblique

Abducens Sphenoid

Anterior aspect of floor of orbit

Passes anteri- Trochlear orly through trochlea, changes direction and attaches to posterior hemisphere of sclera Oculomotor Posterior hemisphere of sclera

Main Actions Elevate upper eyelid

Elevates, adducts, and medially rotates eye Depresses, adducts, and laterally rotates eye Adducts eye Abducts eye Depresses, abducts, and medially rotates eye

Elevates, abducts, and laterally rotates eye

Additional Concept Superior Tarsal Muscle The anterior-most fibers of levator palpebrae superioris are smooth muscle—the superior tarsal muscle. This smooth muscle component is primarily responsible for keeping the upper eyelid raised.

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CHAPTER 7 | HEAD Levator palpebrae superioris Superior oblique

233

Superior rectus

Optic nerve in sheath transversing optic canal Tendinous ring Superior orbital fissure Oculomotor nerve (CN III) Trochlear nerve (CN IV) Pons

Inferior oblique

Abducent nerve (CN VI)

Trigeminal ganglion (CN V)

Medial rectus Lateral rectus

Ciliary ganglion

Inferior rectus

FIGURE 7-7. Innervation of muscles of eyeball.The oculomotor (CN III), trochlear (CN IV), and abducent (CN VI) nerves are distributed to the muscles of the eyeball. The nerves enter the orbit through the superior orbital fissure. CN IV supplies the superior oblique, CN VI supplies the lateral rectus, and CN III supplies the remaining five muscles. (From Moore KL, Dalley AF. Clinically Oriented Anatomy. 5th ed. Baltimore: Lippincott Williams & Wilkins; 2006:970.)

IO

IO

LR

MR MR

LR

SO

IR IR Adduction Abduction

SO

Elevation

Abduction Adduction SR SR

Depression

Depression

Elevation

Abduction

Abduction

FIGURE 7-8. Eye movements. Large arrows indicate the direction of eye movements caused by the various extraocular muscles. Small arrows indicate either intorsion (medial rotation of the superior pole of the eyeball) or extorsion (lateral rotation of the superior pole of the eyeball). IO ⫽ inferior oblique, LR ⫽ lateral rectus, SO ⫽ superior oblique, MR ⫽ medial rectus, IR ⫽ inferior rectus. (From Dudek RW, Louis TM. High-Yield Gross Anatomy. 3rd ed. Baltimore: Lippincott Williams & Wilkins; 2008:289.)

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Clinical Significance Eye Movements The medial walls of the orbits are parallel; therefore, the axis of the eye is not in line with the axis of the orbit. The recti muscles attach via a common tendinous ring at the apex of the orbit and so produce unwanted movements of the eye when they contract—adduction and rotation. The superior and inferior oblique muscles offset the rotation and adduction of the eye by the recti to get a more straightforward elevation or depression. Fascial Sheath of the Eyeball The eye is surrounded by the fascial sheath of the eyeball, which forms a “socket” into which the eyeball sits and that is attached to and pierced by the extraocular muscles. Extensions of the sheath are attached to the orbit as medial and lateral check ligaments that limit adduction and abduction of the eye. The check ligaments blend with the fascia of the inferior rectus and inferior oblique muscles to form the suspensory ligament of the eyeball, a hammocklike sling that supports the eye.The fascial sheath of the eyeball forms the socket into which a prosthetic eye is inserted, still allowing for relatively natural movement because of the connection to the extraocular muscles. Mnemonic To recall the innervation pattern of the extraocular muscles use this “formula”: [SO4LR6]3 Superior Oblique by CN IV; Lateral Rectus by CN VI and all the rest by CN III. Vasculature of the orbit Vessel Arteries Ophthalmic

Origin

Supplies/Gives Rise To

Internal carotid

Central artery of the retina Supraorbital Supratrochlear Dorsal nasal

Ophthalmic

Supplies structures of orbit, face, and scalp Supplies retina Supplies forehead and scalp Supplies nose (continued)

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Vasculature of the orbit (continued) Vessel Lacrimal Ethmoidal (anterior and posterior) Posterior ciliary (short and long) Anterior ciliary Vessel Veins Scleral venous sinus Vorticose Central vein of the retina Superior ophthalmic Inferior ophthalmic

Origin

Supplies/Gives Rise To Supplies eyelids, conjunctiva, and lacrimal gland Supplies ethmoidal air cells and nasal cavity Supplies middle layer of eye

Termination

Drains

Vorticose vein

Aqueous humor from anterior chamber Middle layer of eye Retina

Ophthalmic veins Cavernous sinus or inferior ophthalmic vein Cavernous sinus and Eye and orbit the inferior ophthalmic also drains into the pterygoid venous plexus

Nerves of the orbit (Figure 7-7) Nerve Frontal

Origin Ophthalmic

Nasociliary Ethmoidal (anterior and posterior) Long ciliary

Ophthalmic Nasociliary

Structures Innervated Upper eyelid, scalp, and forehead via two terminal branches—supraorbital and supratrochlear Eye, face, and nasal cavity Sphenoid and ethmoid air cells and nasal cavity

• Eye • Conveys sympathetics to iris and sensation from cornea Ciliary ganglion • Eye Short ciliary • Conveys sympathetics and parasympathetics from CN III to iris and ciliaris • Conveys parasympathetics to the Ophthalmic Lacrimal lacrimal gland from V2 • Conjunctiva and skin of upper eyelid • Presynaptic parasympathetics are conCiliary ganglion Innervated by veyed via CN III accessory oculo• Postganglionics are conveyed via motor nucleus short ciliary nerves to ciliaris and sphincter pupillae

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PARASYMPATHETIC GANGLIA IN THE HEAD Parasympathetic ganglia in the head Ganglia Ciliary

Afferents Accessory oculomotor nucleus via CN III Otic Inferior salivatory nucleus via CN IX Pterygopalatine Superior salivatory nucleus via CN VII branch—greater petrosal nerve Submandibular Superior salivatory nucleus via CN VII branch—chorda tympani

Efferents Postsynaptics innervate sphincter pupillae and ciliaris Postsynaptics innervate parotid gland Postsynaptics innervate oral and nasal mucosa and the lacrimal gland Postsynaptics innervate the sublingual and submandibular glands

Mnemonic The acronym C-O-P-S is a useful way to remember the four parasympathetic ganglia of the head.

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Neck

8

INTRODUCTION The neck supports the head and connects it to the trunk. It not only houses organs of its own, but serves as a passageway for structures coursing between the head and trunk.

NECK Skeleton of the Neck The skeleton of the neck consists of the seven cervical vertebrae—presented with the back, the sternum—presented with the thorax, the clavicles—presented with the upper limb and the hyoid bone. The hyoid bone does not articulate with any other bones. It functions primarily as a muscle attachment for muscles of the tongue and larynx.

Clinical Significance Hyoid Fracture Fractures of the hyoid are common in persons who are strangled. The result is an inability to elevate the hyoid, which makes swallowing and the prevention of ingested substances from entering the airway difficult. Fascia and spaces of the neck (Figure 8-1) The neck is surrounded by a fatty layer of superficial fascia; the deep fascia of the neck divides it into compartments, facilitates movement, and determines the spread of infection.

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Fascia and spaces of the neck (continued) Structure

Description

Superficial cervical fascia • Overlies the deep cervical fascia • Contains the platysma • Contains neurovascular, lymphatic, and fat Deep Cervical Fascia Investing

• Surrounds entire neck like a sleeve • Splits to enclose the sternocleidomastoid and trapezius muscles and submandibular and parotid gland—forms fibrous capsule • Continuous with nuchal ligament

Prevertebral

• Encloses the vertebral column, longus coli, scalenes—anterior, middle and posterior, longus capitis, and deep cervical muscles • An extension of prevertebral fascia forms the axillary sheath—that surrounds the axillary vessels and brachial plexus

Pretracheal

• Encloses the infrahyoid muscles, thyroid gland, trachea, and esophagus • Continuous with buccopharyngeal fascia

Carotid sheath

• Encloses the common carotid artery, internal jugular vein, and vagus nerve • Composed of contributions from investing, prevertebral and pretracheal fascia

Buccopharyngeal fascia

• Encloses the pharynx • Continuous with pretracheal fascia

Spaces of the Neck Retropharyngeal space

• Between prevertebral and buccopharyngeal fascia • Subdivided by alar fascia • Permits movement of the viscera during swallowing • Also called—danger space, because it is a pathway for infection to spread between the neck and posterior mediastinum

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Occipital bone

Pharynx Mandible Hyoid Investing fascia Larynx Superficial cervical fascia (subcutaneous tissue) Pretracheal fascia Trachea Manubrium of sternum

Esophagus

Medial view

Anterior longitudinal ligament Body of vertebra Buccopharyngeal fascia Intervertebral disc Longus colli muscle Prevertebral fascia Pharynx Pharyngeal muscle Retropharyngeal space

FIGURE 8-1. Sections of head and neck demonstrating cervical fascia. (From Moore KL, Dalley AF. Clinically Oriented Anatomy. 5th ed. Baltimore: Lippincott Williams & Wilkins; 2006:1050.)

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Regions of the neck (Figures 8-2, 8-3, and 8-6) The neck is divided into four regions. Region Anterior cervical (anterior triangle of the neck)

Description and Contents • Borders: • Anterior—midline of neck • Posterior—anterior border of sternocleidomastoid • Inferior—junction of midline of neck and sternocleidomastoid • Superior—mandible • Roof—investing layer of deep cervical fascia • Floor—pretracheal fascia investing pharynx, larynx, and thyroid • Nerves in region: • Transverse cervical—sensory to skin of region • Hypoglossal—supplies tongue • Vagus • Glossopharyngeal • Arteries in region: • Common carotid—terminate in region to form internal and external carotid arteries • Internal carotid—no branches in neck; enter cranium via carotid canal • External carotid—terminates as maxillary and superficial temporal arteries; before termination gives: 1. Ascending pharyngeal 2. Occipital 3. Posterior auricular 4. Superior thyroid 5. Lingual 6. Facial • Veins in region: • Internal jugular—begins at jugular foramen as continuation of sigmoid sinus, joins subclavian to form brachiocephalic vein, receives—inferior petrosal sinus, facial, lingual, pharyngeal, and thyroid veins—superior and middle • Anterior jugular • Subdivided by digastric and omohyoid into: • Submental triangle—unpaired; between anterior bellies of digastrics, mandibular symphysis and hyoid; contains—submental nodes (continued)

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Regions of the neck (continued) Region

Lateral cervical (posterior triangle of the neck)

Description and Contents • Submandibular triangle—between mandible and anterior and posterior bellies of digastric; contains—submandibular gland and nodes, hypoglossal nerve (CN XII), facial artery, and vein • Carotid triangle—between superior belly of omohyoid, posterior belly of digastric, and anterior border of sternocleidomastoid; contains—common carotid artery and branches, vagus, spinal accessory and hypoglossal nerves, cervical plexus, thyroid gland, larynx, pharynx, and cervical nodes • Muscular triangle—between superior belly of omohyoid, anterior border of sternocleidomastoid, and midline of neck; contains— infrahyoid muscles, thyroid, and parathyroid glands • Borders: • Anterior—posterior border of sternocleidomastoid • Posterior—anterior border of trapezius • Inferior—clavicle • Superior—junction of sternocleidomastoid and trapezius • Roof—investing layer of deep cervical fascia • Floor—prevertebral layer of deep cervical fascia that covers the middle and posterior scalenes, levator scapulae, and splenius capitis • Nerves in region: • Spinal accessory (CN XI), supplies sternocleidomastoid and trapezius • Brachial plexus—roots and trunks, supplies upper limb • Suprascapular nerve—supplies supra- and infraspinatus • Cervical plexus—C1–C4: give rise to phrenic nerve (C3–C5) that supplies the diaphragm, ansa cervicalis that supplies infrahyoid muscles, and cutaneous branches: lesser occipital, great auricular, transverse cervical, and supraclavicular, emerge from nerve point of the neck—a quarter-sized area midway along the posterior border of sternocleidomastoid (continued)

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Regions of the neck (continued) Region

Description and Contents • Arteries in region: • Transverse cervical—from thyrocervical trunk • Suprascapular—from thyrocervical trunk • Occipital—from external carotid artery • Subclavian—3rd part, supplies upper limb • Veins in the region: • External jugular—formed by junction of retromandibular and posterior auricular veins, terminates in subclavian • Subclavian—drains upper limb, joins internal jugular to form brachiocephalic vein • Subdivided by inferior belly of omohyoid into: • Occipital triangle—superior to omohyoid • Omoclavicular triangle—inferior to omohyoid

Posterior cervical

• Located posterior to anterior border of trapezius • Contains trapezius, suboccipital triangle—lies deep

Additional Concept Subclavian Artery The subclavian artery passes posterior to the anterior scalene, whereas the vein passes anterior. Carotid Artery In the carotid triangle, the common carotid artery divides into internal and external carotid arteries. At the bifurcation is the carotid sinus—a dilation of the internal carotid that functions as a baroreceptor—measures blood pressure, innervated by CN IX. The carotid body also lies near the bifurcation and functions as a chemoreceptor— measures oxygen levels in blood, it is also innervated by CN IX.

Clinical Significance External Jugular Vein The external jugular vein may become prominent and evident throughout its course as a result of increased venous pressure as occurs in heart failure.

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Superficial temporal

Occipital

Facial

Lingual

Internal carotid Carotid sinus

Superior thyroid

FIGURE 8-2. Lateral arteriogram (digital subtraction) of the head and neck region with a blocked internal carotid artery. The most common location of atherosclerosis in the carotid artery is at the bifurcation of the common carotid artery. Carotid artery plaques are usually ulcerated plaques. (From Dudek RW, Louis TM. HighYield Gross Anatomy. 3rd ed. Baltimore: Lippincott Williams & Wilkins; 2008:268.)

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Muscles of the neck (Figures 8-3 and 8-6) Proximal Muscle Attachment Sternocle- Manubrium and idomastoid clavicle

Distal Attachment Mastoid process and superior nuchal line Suprahyoids—Superior to the Hyoid Mylohyoid Mylohyoid line Mylohyoid raof mandible phe and hyoid Digastric Anterior belly— Intermediate mandible; post- tendon aterior belly— tached to hyoid temporal bone by connective tissue Geniohyoid Inferior mental Hyoid spine of mandible Stylohyoid Styloid process Infrahyoids—Inferior to the Hyoid Omohyoid Scapula Hyoid SternoSternum Thyroid thyroid cartilage SternoHyoid hyoid Thyrohyoid Thyroid cartilage Prevertebral Longus coli C1–C6 vertebrae C3–T3 vertebrae Longus Occipital bone C3–C6 capitis vertebrae Rectus C1 vertebra capitis (anterior and lateral) Anterior C4–C6 1st rib scalene vertebrae Middle scalene Posterior 2nd rib scalene

Innervation Spinal accessory

Main Actions Laterally flexes and extends neck; rotates head

Nerve to mylohyoid (V3) Anterior belly—nerve to mylohyoid (V3); posterior belly—facial C1 via hypoglossal

Elevates hyoid Depresses mandible, elevates hyoid

Elevates hyoid

Facial Ansa cervicalis Depresses hyoid

C1 via hypoglossal Anterior rami Flexes and of C2–C6 rotates neck Anterior rami Flexes head of C1–C3 Anterior rami of C1–C2

Anterior rami cervical spinal nerves Laterally flexes neck

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The trapezius is described with the shoulder region of the upper limb.The platysma is described with the muscles of the face.

Additional Concept Innervation The ansa cervicalis is a loop in the cervical plexus consisting of fibers from the first three cervical nerves. Fibers from C1–C2 form the superior root, whereas fibers from C2–C3 form the inferior root that unite to form the ansa cervicalis.

Clinical Significance Torticollis Torticollis is a contraction of the cervical muscles, most commonly the sternocleidomastoid, which produces a twisting of the neck and slanting of the head. Root of the neck The root of the neck is the area of junction between the inferior aspect of the neck and the superior aspect of the thorax. Feature Description Nerves • Vagus • Right recurrent laryngeal • Left recurrent laryngeal • Phrenic • Sympathetic trunks

Arteries

• Brachiocephalic trunk • Subclavian— right and left

Veins

• External jugular • Anterior jugular • Subclavian

Significance • Vagus—located in carotid sheath; right recurrent laryngeal arises after right vagus passes over subclavian artery, left recurrent laryngeal arises after left vagus nerve passes over arch of aorta; recurrent laryngeals ascend in tracheoesophageal groove to supply trachea, esophagus and larynx • Phrenic—C3–C5; sensory and motor to diaphragm • Sympathetic trunks—3 ganglia: superior, middle, and inferior; postsynaptics conveyed via gray communicating branches to cervical spinal nerves, cardiopulmonary splanchnic nerves to thoracic viscera, and the periarterial plexus to head and neck viscera • Brachiocephalic trunk terminates by dividing into right common carotid and right subclavian arteries • Right subclavian is a branch of brachiocephalic trunk; left is a branch of the arch of the aorta • External jugular drains scalp and face; empties into subclavian (continued)

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Root of the neck (continued) Feature Description

Significance • Anterior jugular formed by submandibular veins, unites with contralateral counterpart to form the jugular venous arch superior to sternum; empties into external jugular • Subclavian vein begins as axillary vein crosses 1st rib; ends by joining internal jugular vein to form brachiocephalic at the venous angle—place where thoracic duct and right lymphatic duct typically join venous system on left and right sides respectively

Styloglossus Hypoglossal nerve (CN XII) Nerve roots of cervical plexus

Hypoglossus

C1 C2

Genioglossus

C3

Geniohyoid

Internal carotid artery Hypoglossal nerve (CN XII) Ansa Inferior root cervicalis Superior root

Thyrohyoid Omohyoid

Sternohyoid

Lateral view Sternothyroid

FIGURE 8-3. Distribution of hypoglossal nerve (CN XII). CN XII leaves the cranium through the hypoglossal canal and passes deep to the mandible to enter the tongue, where it supplies all intrinsic and extrinsic lingual muscles, except the palatoglossus. CN XII is joined immediately distal to the hypoglossal canal by a branch conveying fibers from the C1 and C2 loop of the cervical plexus. These fibers hitch a ride with CN XII, leaving it as the superior root of the ansa cervicalis and the nerve to the thyrohyoid muscle. (From Moore KL, Dalley AF. Clinically Oriented Anatomy. 5th ed. Baltimore: Lippincott Williams & Wilkins; 2006:1105.)

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Additional Concept Subclavian Arteries The subclavian arteries are divided into three parts by the anterior scalene muscle. Part 1 is proximal, Part 2 is deep, and Part 3 is distal to the muscle. Part 1 branches— ■ ■ ■

vertebral—runs superiorly in transverse cervical foramina, enters cranium through foramen magnum to supply brain internal thoracic—supplies structures in thorax thyrocervical—gives rise to inferior thyroid artery: to neck viscera, suprascapular: to scapular region, transverse cervical: to lateral cervical region, and ascending cervical: to neck musculature

Part 2 branches— ■

costocervical trunk—gives rise to superior intercostal: to first two intercostal spaces and deep cervical: to neck musculature

Part 3 branches— ■

dorsal scapular—supplies rhomboids and levator scapulae and the scapular region

Sympathetic Trunks The inferior cervical and first thoracic sympathetic ganglia often fuse to form the cervicothoracic or stellate ganglion. Mnemonic Phrenic Nerve Nerve roots in the phrenic nerve: C3, C4, and C5 keep the diaphragm alive.

Clinical Significance Subclavian Vein The subclavian vein is a common point of entry for central line placement. Lymphatics of the neck Superficial lymphatic drainage of the neck is to superficial cervical lymph nodes located along the external jugular vein. Superficial drainage and drainage from deep structures is conveyed to deep cervical lymph nodes, generally

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found along the internal jugular vein. Efferents from the deep cervical nodes form the jugular lymphatic trunks that empty lymph into the right lymphatic or thoracic duct. Structure Thyroid

Description Lymphatic vessels communicate in a network around the fibrous capsule of the gland

Drainage The network of vessels drain to prelaryngeal, pretracheal, and paratracheal nodes, which drain into deep cervical nodes

Parathyroid

Lymphatic vessels drain glands

Parathyroid vessels drain into deep cervical and paratracheal nodes

Larynx

Lymphatic vessels accompany laryngeal arteries

• Vessels superior to vocal folds follow superior laryngeal artery to the deep cervical nodes • Vessels inferior to vocal folds drain into pretracheal or paratracheal nodes, which drain to deep cervical nodes

Pharynx

Lymphatic vessels from the tonsils drain to nodes near the angle of the mandible

The lymph from the tonsils is referred to the jugulodigastric node

Additional Concept Tonsillar Ring The palatine, lingual, tubal, and pharyngeal tonsils form the tonsillar ring (Waldeyer’s Ring)—a ring of lymphatic tissue around the superior aspect of the pharynx.

Clinical Significance Tonsillectomy Tonsillectomy is performed by removing the palatine tonsil and its fascia from the tonsillar bed. Inflammation of the pharyngeal tonsils is adenoiditis. Inflamed adenoids may interfere with nasal breathing and allow infection to spread to the middle ear cavity through the auditory tube.

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ENDOCRINE ORGANS IN THE NECK Thyroid and parathyroid (Figures 8-2 and 8-6) The endocrine organs of the neck include the thyroid and parathyroid glands. The thyroid gland—located in the anterior aspect of the neck, produces thyroid hormone and calcitonin, whereas the four parathyroid glands—embedded in the posterior aspect of the thyroid gland—produce parathyroid hormone. Gland Thyroid

Parathyroid

Feature Description • Lobes—right and left are • Gland is surrounded by a connected by an isthmus fibrous capsule and the • Arterial supply—superior pretracheal layer of deep and inferior thyroid cervical fascia arteries • Superior and middle thyroid • Venous drainage— veins drain into the internal superior, middle and jugular veins, whereas the inferior thyroid veins inferior veins drain the • Innervation—sympathetic brachiocephalic veins • Sympathetic innervation is from the cervical sympathetic ganglia; the postganglionics follow arteries to the gland and cause vasoconstriction • Arterial supply—inferior Sympathetic innervation is thyroid glands from the cervical sympathetic • Venous drainage—drain ganglia; the postganglionics into the thyroid veins follow arteries to the gland • Innervation—sympathetic and cause vasoconstriction

Additional Concept Thyroid Ima Artery The thyroid ima artery is present in approximately 10% of people. It has a variable origin, often from the aorta, and, when present, supplies the trachea and isthmus of the thyroid. This midline artery must be considered during procedures in the midline of the neck.

Clinical Significance Goiter Enlargement of the thyroid gland—goiter, results from iodine deficiency. The enlarged gland may compress nearby structures.

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Epiglottis Vestibular fold Vocal fold Aryepiglottic fold

Rima glottidis

FIGURE 8-4. Laryngeal cartilages. Photograph depicting the structures observed during inspection of the vocal cords using a laryngeal mirror. (From Dudek RW, Louis TM. High-Yield Gross Anatomy. 3rd ed. Baltimore: Lippincott Williams & Wilkins; 2008:280.)

RESPIRATORY STRUCTURES IN THE NECK Larynx and trachea (Figures 8-2, 8-4, and 8-5) The larynx routes air into the respiratory tract, food into the esophagus, blocks the airway during swallowing, and produces the voice. The trachea, presented in detail in the thorax chapter (see Chapter 1), extends from the inferior border of the cricoid cartilage of the larynx to its termination in the thorax at the level of the sternal angle as the right and left primary bronchi. Structure Laryngeal inlet

Laryngeal vestibule

Description Space bounded by aryepiglottic folds and epiglottis

Significance Entrance into the larynx at which point the vestibule of the larynx is continuous with the laryngopharynx Space bounded by laryngeal Space contained between inlet superiorly and vestithe quadrangular membrane bular folds inferiorly (continued)

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Larynx and trachea (continued) Structure

Description

Significance

Laryngeal ventricle

Lateral extension of laryngeal cavity between vestibular and vocal folds Space bounded by vocal folds superiorly and inferior border of cricoid cartilage inferiorly Mucosa covered folds that project into laryngeal cavity

Laryngeal saccule—blindended, mucous-secreting pocket that opens into ventricle Continuous inferiorly with lumen of trachea

Infraglottic cavity

Vestibular folds

Vocal folds

Glottis

• Contain vestibular ligament • Space between—rima vestibuli • Adducting vestibular folds prevents ingested substances from entering airway • Contain vocal ligament and vocalis: lateral to vocal ligaments, involved in whispering • Adducting vocal folds prevents ingested subances from entering airway Vocal folds and space betVarying the tension and ween them—rima glottidis length of the vocal folds varies size of rima glottidis to produce varying pitch for speech

Additional Concept Blood Supply to the Larynx The superior laryngeal artery, a branch of the superior thyroid artery, passes through the thyrohyoid membrane with the internal laryngeal nerve to anastomose with the internal laryngeal artery, a branch of the inferior thyroid artery that accompanies the inferior laryngeal nerve. The venous drainage parallels arterial supply.

Clinical Significance Valsalva Maneuver In the Valsalva maneuver, the vestibular and vocal folds are tightly adducted after a deep inspiration. Contraction of the abdominal muscles increases intrathoracic and intraabdominal pressures, thereby impeding venous return to the heart.

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Skeleton of the larynx (Figure 8-5) The skeleton of the larynx consists of nine cartilages that are connected by membranes and ligaments. Structure Description Significance Thyroid cartilage Composed of 2 laminae— • The anterior junction of possess a set of superior the laminae form the and inferior horns on their laryngeal prominence posterior borders or Adam’s apple • The superior horn and border of the cartilage attach to the hyoid by the thyrohyoid membrane • The inferior horns articulate with the cricoid cartilage at the cricothyroid joint Cricoid cartilage Complete cartilaginous ring • Connected to thyroid inferior to thyroid cartilage cartilage by median cricothyroid ligament • Connected to 1st tracheal ring by cricotracheal ligament Epiglottic Mucous covered, leaf• Inferior aspect attached to cartilage shaped anterior border of thyroid by thyroepiglottic the laryngeal inlet ligament • Anterior aspect attached to hyoid by hypoepiglottic ligament Arytenoid • 3 sided, pyramidal-shaped: • Apex: articulates with cartilages (2) 1. Apex corniculate cartilages and 2. Vocal process is embedded within the 3. Muscular process aryepiglottic fold • Articulate with cricoid • Vocal process: posterior cartilage at cricoaryteattachment for vocal noid joints ligament • Muscular process: attachment for lateral and posterior cricoarytenoid muscles Corniculate • Articulate with apex of Provide structure to aryepicartilages (2) arytenoid cartilages glottic folds • Embedded within aryepiglottic fold Cuneiform Embedded within aryepicartilages (2) glottic fold (continued)

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Skeleton of the larynx (continued) Structure Thyrohyoid membrane

Description Attaches thyroid cartilage to hyoid

Vocal ligament

Extend from laryngeal prominence anteriorly to vocal process of arytenoid cartilages posteriorly Extends from arytenoid cartilages to sides of epiglottic cartilages

Quadrangular membrane

Conus elasticus • Superior border—vocal ligaments • Lateral extensions— lateral cricothyroid ligaments Joints Cricothyroid

Cricoarytenoid

Articulation between inferior horns of thyroid and cricoid cartilage Articulation between arytenoid cartilages and cricoid cartilage

Significance • Midline thickening is median thyrohyoid ligament • Lateral thickenings form lateral thyrohyoid ligaments • Thickened, free superior border of conus elasticus • Covered by mucosa to form vocal fold • Free inferior border— vestibular ligament, covered by mucosa to form vestibular fold • Free superior border— aryepiglottic ligament, covered by mucosa to form aryepiglottic fold • Continuous anteriorly with median cricothyroid ligament • Close tracheal inlet when vocal ligaments are approximated Movements: rotation and gliding of thyroid on the cricoid Movements: sliding of arytenoid cartilages—toward or away from each other, tilting and rotation of arytenoids

Clinical Significance Fracture Laryngeal fractures are common. They may produce hemorrhage and edema, obstruction of the airway, and hoarseness. Muscles of the larynx The extrinsic muscles of the larynx include the supra- and infrahyoid musculature described with the muscles of the neck and are involved in moving the larynx as a whole— suprahyoids elevate the larynx; infrahyoids depress the larynx.

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Epiglottis Lesser horn of hyoid

Greater horn of hyoid

Body of hyoid Thyrohyoid membrane

Superior horn Thyroid cartilage Oblique line Inferior horn

Cricoid cartilage

Laryngeal prominence

Median cricothyroid ligament Cricotracheal ligament

Lamina Arch

1st 2nd

Tracheal cartilages

3rd

Right lateral view

FIGURE 8-5. Skeleton of larynx, right lateral view. (From Moore KL, Dalley AF. Clinically Oriented Anatomy. 5th ed. Baltimore: Lippincott Williams & Wilkins; 2006:1090.)

The intrinsic muscles of the larynx move the skeleton of the larynx to alter tension on the vocal folds and the size of the rima glottidis.

Muscle Vocalis

Proximal Attachment Arytenoid cartilage

Distal Attachment Vocal ligament

Cricothyroid Cricoid cartilage Thyroid cartilage

Innervation Inferior laryngeal

External laryngeal

Main Actions Alter tension on vocal ligament for whispering Tenses vocal ligament (continued)

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Muscles of the larynx (continued) Muscle Thyroarytenoid Lateral cricoarytenoid

Proximal Distal Attachment Attachment Innervation Thyroid cartilage Arytenoid Inferior cartilage laryngeal

Main Actions Relaxes vocal ligament

Cricoid cartilage

Adducts vocal folds

Posterior cricoary tenoid Transverse Arytenoid and oblique cartilage arytenoids

Abducts vocal folds Contralateral arytenoid cartilage

Alter tension on vocal ligament

Additional Concept Innervation All intrinsic laryngeal musculature is innervated by branches of CN X. The external and internal laryngeal nerves are branches of the superior laryngeal nerve, which is a branch of CN X. The internal laryngeal nerves supplies sensory innervation superior to the vocal folds, whereas the external laryngeal nerves supplies the cricothyroid muscle. Sensory innervation inferior to the vocal folds and all of the remaining intrinsic musculature is supplied by the recurrent laryngeal nerve, via the inferior laryngeal branch.

ALIMENTARY STRUCTURES IN THE NECK Pharynx and esophagus (Figure 8-1) The pharynx is the fibromuscular tube that serves as a common route for air and ingested substances. It extends from the base of the cranium to the inferior border of the cricoid cartilage of the larynx. It is divided into three parts based on what region/structure it lies posterior to and communicates with: (1) nasopharynx, (2) oropharynx, and (3) laryngopharynx. The esophagus, presented in the thorax chapter (see Chapter 1), extends from the pharyngoesophageal junction

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to its termination in the abdomen at the cardial orifice of the stomach. It is composed of voluntary, skeletal muscle in its upper third, a mixture of skeletal and smooth muscle in its middle third, and involuntary, smooth muscle as its inferior third. The innervation mirrors the musculature—the superior half receives somatic motor and sensory innervation, whereas the inferior half receives autonomic (vagal parasympathetic and sympathetic) and visceral sensory innervation. Structure Nasopharynx

Description • Posterior to nasal cavity • Extends inferiorly to level of soft palate • Pharyngeal tonsils— located on posterior wall • Auditory tube—opens on posterolateral wall • Salpingopharyngeal fold—extends from torus tubaris to blends with pharyngeal muscles

Oropharynx

• Posterior to oral cavity • Between soft palate and epiglottis • Palatine tonsils— located between palatoglossal and palatopharyngeal arches

Laryngopharynx • Posterior to larynx • Between epiglottis and cricoid cartilage • Communicates anteriorly with larynx at laryngeal inlet

Significance • Communicates with nasal cavity via posterior choanae • Pharyngeal tonsils— aggregate of lymphatic tissue • Auditory tube (pharyngotympanic tube)—opening surrounded by cartilaginous torus tubaris and lymphatic elements—the tubal tonsil • Salpingopharyngeus underlies the mucosal that forms the fold; its contraction opens the auditory tube during swallowing • Receives bolus of food from oral cavity during swallowing • Palatine tonsils (tonsils)— aggregate of lymphatic tissue that lie in the tonsillar bed: formed by the superior constrictor and pharyngobasilar fascia—that fascia that fills space between the superior constrictor and the cranium • Walls formed by middle and inferior constrictor, palatopharyngeus, and stylopharyngeus muscles • Piriform recess— depression on each side of laryngeal inlet between pharyngeal wall and aryepiglottic fold

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Additional Concept Swallowing Swallowing has three phases: 1. Stage 1: voluntary; food is formed into bolus and pushed into oropharynx 2. Stage 2: involuntary; soft palate elevates, pharynx widens and shortens 3. Stage 3: involuntary; pharyngeal constrictors force food inferiorly into esophagus Blood Supply to the Pharynx The longitudinally oriented pharynx receives branches from a host of arteries throughout its course, including tonsillar, ascending and descending palatine, lingual, and ascending pharyngeal arteries.Venous drainage parallels arterial supply.

Clinical Significance Piriform Fossa The superior laryngeal artery and internal and inferior laryngeal nerves lie just deep to the mucosa of the piriform fossa and are subject to damage when ingested objects become lodged here. Muscles of the pharynx (Figures 8-3 and 8-6) The muscles of the pharynx are arranged into an external circular layer and an internal longitudinal layer. All laryngeal muscles are voluntary. Proximal Muscle Attachment External Superior Pterygomandiconstrictor bular raphe, mandible, tongue, pterygoid hamulus Middle Stylohyoid constrictor ligament and hyoid bone Inferior Thyroid and constrictor cricoid cartilage

Distal Attachment

Innervation

Pharyngeal Pharyngeal tubercle of plexus occipital bone and pharyngeal raphe Pharyngeal raphe

Main Actions Constricts pharynx

(continued)

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Muscles of the pharynx (continued) Proximal Muscle Attachment Internal PalatoPalatine pharyngeus aponeurosis Stylopharyngeus Salpingopharyngeus

Distal Attachment Pharynx

Styloid process of temporal bone Torus tubaris of of auditory tube

Innervation

Main Actions

Pharyngeal plexus

Tenses soft palate, elevates pharynx Elevates pharynx

CN IX Pharyngeal plexus

Additional Concept Fascia of the Pharynx The fascia covering the internal aspect of the pharyngeal constrictors is pharyngobasilar fascia, whereas the fascia on their external surface is buccopharyngeal fascia. The pharyngobasilar fascia combines with the buccopharyngeal

Pharyngobasilar fascia

Superior constrictor

CN IX

Glossopharyngeal nerve (CN IX)

CN XI

Internal jugular vein Internal carotid artery

CN XII Spinal accessory nerve (CN XI) Sternocleidomastoid

Styloid process Stylohyoid Digastric, posterior belly

Sensory ganglion of vagus nerve (CN X)

Stylopharyngeus

Hypoglossal nerve (CN XII) Superior cervical sympathetic ganglion

Pharyngeal plexus Middle constrictor

Superior laryngeal nerve Common carotid artery Sympathetic trunk and plexus Vagus nerve (CN X)

Pharyngeal raphe Inferior constrictor Thyroid gland Inferior thyroid artery Cricopharyngeal part of inferior constrictor

Left recurrent laryngeal nerve

Right recurrent laryngeal nerve Esophagus

Posterior view

FIGURE 8-6. Pharynx and cranial nerves, posterior view. (From Moore KL, Dalley AF. Clinically Oriented Anatomy. 5th ed. Baltimore: Lippincott Williams & Wilkins; 2006:1105.)

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fascia superior to the superior constrictor to fill the gap between the superior constrictor and the cranium. Innervation The musculature of the pharynx, with the exception of the stylopharyngeus, is supplied by the pharyngeal plexus. Motor fibers in the pharyngeal plexus are from CN X, whereas sensory fibers are from CN IX. The superiormost part of the nasopharynx receives sensory innervation from V2. Constrictor Muscles The constrictors are arranged like a stack of nested flower pots, with gaps between each. The gaps allow structures to enter and leave the pharynx. The four gaps between: 1. superior constrictor and cranium—conveys levator palati, auditory tube, and ascending palatine artery 2. superior and middle constrictors—conveys stylopharyngeus, stylohyoid ligament, and the glossopharyngeal nerve 3. middle and inferior constrictors—conveys internal laryngeal nerve and superior laryngeal artery 4. inferior constrictor and esophagus—conveys recurrent laryngeal nerve and inferior laryngeal artery; the recurrent laryngeal nerve changes names to the inferior laryngeal nerve upon entering the larynx.

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List of Mnemonics Abdominal wall muscles, 38 Anterior forearm flexors, 175–176 Arterial anastomosis at elbow, 178 Axillary artery branches, 167 Back muscles, 124 Biceps brachii attachments, 170 Brachial plexus, 189 Carpal bones, 180 Cubital fossa, 185 Elbow movement, 195f Eye innervation, 234 Femoral triangle, 147, 148 Hand musculature innervation, 182 Inhaled objects, 30 Intercostal neurovascular elements, 13

260

Interossei function, 182 Intertubercular groove muscle attachments, 169 Lateral rotators of hip joint, 130 Leg muscles, 140 Long thoracic nerve, 165 Lower limb, 157 Lumbar plexus, 40 Pectoral nerves, 190 Pelvis nerves, 88 Peritoneal cavity, 47 Phrenic nerves, 247 Popliteal fossa, 147 Radial nerve, 177 Scalp, 202 Thigh muscles, 135 Thoracoacromial trunk branches, 167 Thorax, 15

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Index Abdomen area, 33–34 cavity, 33 embryologic arterial supply, 53 hernia direct inguinal, 44, 47 indirect inguinal, 44, 47 intraperitoneal organs, 47 jejunum, 46f lymphatics, 74–76 quadrants, 34 regions, 33 Abdominal wall anterolateral, 37 arcuate line, 36 conjoint tendon, 36 endoabdominal fascia, 35 guarding reflex, 38 iliopubic tract, 36 inguinal canal, 34 deep inguinal ring, 34 inguinal ligament, 36 lacunar ligament, 36 pectineal ligament, 36 subinguinal space, 34 superficial inguinal ring, 35 investing fascia, 35 parietal peritoneum, 35 posterior, 37–38 rectus sheath, 35, 36 structures, 35–36 superficial fascia, 35 Aorta abdominal, 22f, 39, 72 arch of, 17, 22f thoracic, 13 Arm, 167–172. See also Upper limb Artery(ies), 60f alveolar inferior, 216 posterior superior, 216

angular, 213 appendicular, 57 arcuate, 145 arterial arcades, 53 atrioventricular nodal branch, 25 auricular deep, 216 posterior, 213 axillary, 166, 171 basilar, 209 brachial, 172 compression of, 172 deep, 172 brachiocephalic trunk, 17, 22f, 245 bronchial, 14 right/left, 31 carotid, 242 common, 240 external, 240 internal, 208, 240, 243f left common, 17, 22f carpal arch dorsal, 183 palmar, 183 celiac trunk, 50, 61, 62f, 65, 67, 69 cerebral anterior, 209 arterial circle, 209, 210 middle, 209 posterior, 209 circumflex branch, left, 25 colic left, 57 middle, 57 right, 57 communicating anterior, 209 posterior, 209 coronary, 26 left, 25 right, 22f, 25 cremasteric, 39, 40, 42

261

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262

INDEX

Artery(ies) (continued) costocervical trunk, 247 cystic, 60f, 65 digitals, dorsal, 146 dorsalis pedis, 145 dorsal scapular, 247 ductus deferens, 39, 42, 102 epigastric inferior, 38 superficial, 39, 136 superior, 38 esophageal, 14 ethmoidal, 235 facial, 213 femoral, 136, 137 deep, 136 femoral circumflex lateral, 137 medial, 137 fibular, 142 gastric left, 50 right, 50 short, 50 gastroduodenal, 50, 67 gastro-omental left, 50 right, 50 genicular, 141 descending, 137 gluteal inferior, 89, 93, 130 superior, 89, 130 gonadal, 89 right/left, 72 hepatic, 50, 60f, 61, 65, 67 common, 60f left branches, 60f right branches, 60f right/left, 61, 65 humeral, circumflex, 166, 172 ileocolic, 57 iliac deep circumflex, 39 internal, 89 anterior, 89 posterior, 89 superficial circumflex, 39, 136 iliolumbar, 89 inferior epigastric, 45 infraorbital, 216

intercostal anterior, 6, 10 posterior, 6, 10, 14 interosseous anterior, 177 common, 177 posterior, 177 recurrent, 177 interventricular anterior, 22f, 25 posterior, 25 lacrimal, 235 lower limb, 131f lumbar, 39 mammary branch lateral, 10 medial, 10 marginal, 57 left, 25 right, 25 maxillary, 216, 218 medullary, 120 meningeal, middle, 205, 216 mental, 213 mesenteric inferior, 57, 62f superior, 53, 57, 60f, 62f, 67 metatarsals, dorsal, 146 musculophrenic, 38 nasal dorsal, 234 lateral, 213 obturator, 89, 93, 136 occipital, 213, 242 ophthalmic, 234 palatine, descending, 216 palmar arch deep, 182 superficial, 182 palmar digitals common, 183 proper, 183 pancreatic caudal, 67 dorsal, 67 great, 67 pancreaticoduodenal anterior/posterior inferior, 67 anterior/posterior superior, 67

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INDEX inferior, 53 superior, 52–53 pericardial, 14 phrenic inferior, 74 superior, 14 plantar arch, 146 deep, 146 digitals, 146 lateral, 146 medial, 146 metatarsals, 146 popliteal, 141 posterior ciliary, 235 princeps pollicis, 183 pudendal, 110 deep external, 137 internal, 89, 94, 130, 136 superficial external, 137 pulmonary, right/left, 31 pulmonary trunk, 22f radial, 177 radialis indicis, 183 radicular, anterior/posterior, 120 rectal inferior, 57 middle, 57, 89, 94 superior, 57 renal, 74 right/left, 72 retina, central artery of, 234 sacral, lateral, 89 scapular, circumflex, 166, 172 scrotal anterior, 40 posterior, 40 segmental, 72, 119 sigmoid, 57 sinuatrial nodal branch, 25 sphenopalatine, 216 spinal anterior, 119 posterior, 119 splenic, 50, 60f, 67, 69 subclavian, 242 left, 17, 22f right/left, 165, 245 subcostal, 6, 14, 39 subscapular, 166, 172 supraorbital, 213, 234

263

suprarenal inferior, 74 middle, 74 superior, 74 suprascapular, 166, 242 supratrochlear, 213, 234 tarsal, lateral, 145 temporal deep, 216 superficial, 213 testicular, 39, 42 thoracic internal, 6, 166 lateral, 166 superior, 166 thoracoacromial, 10, 166 thoracodorsal, 166, 172 thyrocervical trunk, 166 thyroid ima, 249 tibial anterior, 142 posterior, 142 transverse cervical, 166 transverse facial, 213 tympanic, anterior, 216 ulnar, 177 anterior recurrent, 177 inferior collateral, 172 posterior recurrent, 177 superior collateral, 172 umbilical, 89 upper limb, 161f uterine, 89 vaginal, 89, 93, 94, 96 vertebral, 116, 209 vesical inferior, 89, 93, 94 superior, 89, 93 Back suboccipital triangle, 124–125 Biliary tree, cholangiograph, 64f Bone marrow harvesting, with sternal puncture, 3 Bones calcaneus, 142 capitate, 178 clavicle, 157 fracture, 162 coccyx, 126 Colles’ fracture, 173 coxal, 126–127 cuboid, 143

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264

INDEX

Bones (continued) cuneiform intermediate, 143 lateral, 143 medial, 143 epiphysial rim, 114 ethmoid, 197 fibula, 138 fracture, 139 frontal, 197 hamate, 178 hard palate, 196 hip, 79–81, 126–127 gluteal lines, 79 hip pointer, 129 iliac crest, 79 ilium, 79 ischium, 79 humerus, 160f, 167–169 fracture, 169 ilium, 126–127 incus, 227 inferior nasal concha, 200 inferior articular processes, 115 ischium, 127 lacrimal, 200 lamina, 115 lower limb, 128f bones, 132 lunate, 178 malleus, 227 mandible, 198–199 fractures, 201 lingula, 199 maxilla, 198 metacarpals, 179 fracture, 180 metatarsals, 143 nasal, 200 navicular, 143 occipital, 197 palatine, 200 parietal, 197 pedicle, 115 pelvic, 126–127 pelvis, 78–81 acetabular notch, 79 acetabulum, 79 gluteal lines, posterior, 80 radiograph, 82f phalanges distal, 143, 179 middle, 143 proximal, 143

pisiform, 178 pubic arch, 79 pubis, 81, 127 radius, 160f, 173 sacrum, 126 scaphoid, 178 fracture, 179f scapula, 157–158 shoulder, 157–159, 160f sphenoid, 197–198 spinous process, 115 stapes, 227 sternum, 2 superior articular processes, 115 talus, 142 temporal, 199–200 styloid process, 173 thoracic vertebrae, 2 tibia, 137–138 fracture, 138 transverse processes, 115 trapezium, 178 trapezoid, 178 triquetrum, 178 typical ribs of, 1 ulna, 160f olecranon fracture, 173 uncinate process, 115 upper limb, 160f vertebral arch, 114, 116 vertebral canal, 116 vertebral foramen, 114, 116 vertebral notches, 115 vomer, 200 zygomatic, 200 zygomatic arch, 196 Brain, 202–210. See also Cranium; Head apertures lateral, 208 median, 208 areas, 202 brainstem, 202 cerebellum, 202 cerebral aqueduct, 208 cerebrovascular accident, 209 choroid plexus, 208 concussion, 202 contusion, 202 diencephalon, 202 dural folds cerebellar falx, 206 cerebellar tentorium, 206

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INDEX cerebral falx, 206 sellar diaphragm, 206 dural sinuses, 206–207 cavernous, 207, 208 confluence, 207 inferior sagittal, 207 occipital, 207 petrosal, 207 sigmoid, 207 straight, 207 superior sagittal, 206 transverse, 207 epidural space, 205 interventricular foramina, 208 meninges, 204, 205 arachnoid mater, 204, 205 granulations, 205, 208 trabeculae, 205 dura mater, 204, 205 pia mater, 204, 205 stroke, 209 subarachnoid cisterns, 208 subarachnoid space, 205, 208 subdural space, 205 ventricular system, 208 fourth ventricle, 208 lateral ventricles, 208 third ventricle, 208 Breast area, 8 areola, 8 axillary process, 9 lactiferous duct, 9 lactiferous sinus, 9 mammary glands, 8 nipple, 8 quadrants, 10 retromammary space, 10 structure, 8–9, 9f suspensory ligaments, 9 Clitoris, 100 Cranium, 196–202 bones, 196–201 neurocranium, 196 scalp, 201 viscerocranium, 196–201 Ear, 226–228f auditory tube, 227 bony labyrinth, 227

cochlea, 227 external, 227 infection, 228 inner, 227 membranous labyrinth, 227 middle, 227 organ of Corti, 227 saccule, 227 semicircular canals, 227 tympanic membrane, 227 utricle, 227 Esophagus, 13, 16, 239f, 255 constrictions, 14 pyrosis, 48 sphincters, 48 structure, 48 varices, 48 Eye. See Orbit Face, 209–215, 212f Foot, 142–146 arches of, 147 avulsion, 143 fourth compartment, 151 inversion injury, 156f plantar aponeurosis, 152 plantar fasciitis, 152 Forearm, 173–178 elbow tendonitis, 176 tennis elbow, 176 Gallbladder, 60f bile duct, common, 63 body, 63 cholangiograph, 64f cystic duct, 63 fundus, 63 gall stones, 64f hepatopancreatic ampulla, 63 sphincter, 63 neck, 63 spiral valve, 63 Genitalia, female, 101f external, 99 external os, 95, 96 frenulum of the clitoris, 99 of the labia minora, 99

265

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266

INDEX

Genitalia, female (continued) internal, 95–96 internal os, 96 labia major, 99, 111 minora, 99, 111 mons pubis, 99, 111 ovaries, 98 prepuce of the clitoris, 99 pudendal cleft, 102 uterine tubes, 97 uterus, 96 vagina, 95 vaginal fornices, 95 vaginal vestibule, 95, 102 vulva, 102 Genitalia, male bulbourethral glands, 104 ductus deferens, 102 ejaculatory ducts, 102, 103 external, 106 internal, 102–104 prostate, 102, 103–104, 105f fibrous capsule of, 103 prostatic sinuses, 103 prostatic utricle, 103 seminal colliculus, 103 seminal glands, 102–103 vasectomy, 104 Gluteal region, 126–132 acetabulum, 129 Hand, 178–183 Head. See also Brain; Cranium connective tissue, 201 loose, 201 headache, 205 parasympathetic ganglia ciliary, 236 otic, 236 pterygopalatine, 236 submandibular, 236 pericranium, 201 pterygopalatine fossa, 217–218 pterygomaxillary fissure, 218 sphenopalatine foramen, 218 scalp, 201 scalp trauma, 201 skin, 201 sphenomandibular ligament, 199

temporal region intertemporal fossa, 215 structure, 215 temporal fossa, 215 Heart, 19–21 aortic sinuses, 21 aortic valve, 21, 23 aortic vestibule, 21 apex of, 22f atrioventricular valves, right/left, 20 atrium left, 21 right, 20 auricle, 21 left, 22f, 22f right, 22f auscultation of, 23 bicuspid valve, 23 chordae tendineae, 20, 22f conus arteriosus, 21, 22f coronary artery disease, 26 crista terminalis, 20 ductus arteriosus, 32 endocardium, 22 epicardium, 22 fibrous skeleton, 20 foramen ovale, 23 interatrial septum, 20 interventricular septum, 20 ligamentum arteriosum, 16, 22f, 32 muscular interventricular septum, 22f myocardium, 22 papillary muscles, 20, 22f pectinate muscles, 19 pulmonary sinuses, 21 pulmonary valve, 21, 23 septal defects, 23 septomarginal trabecula, 21 sinus venarum, 20 sulcus terminalis, 20 supraventricular crest, 21 surfaces, 19 trabeculae carneae, 19 tricuspid valve, 22f, 23 ventricle, 23 left, 21, 22f right, 21 walls of, 22

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INDEX Joint(s) acromioclavicular, 192 dislocation, 195 ankle, 154 atlantoaxial, 117 atlanto-occipital, 117 carpometacarpal, 194 costochondral, 7 costotransverse, 8 costovertebral, 8 cricoarytenoid, 253 cricothyroid, 253 elbow, 193, 195f femorotibial, 153 glenohumeral, 192–193 dislocation, 195 hip, 153 humeroradial, 193 humeroulnar, 193 intercarpal, 194 interchondral, 7 intercostal 1st, 7 2nd-7th, 7 interphalangeal, 155, 194 intertarsal, 155 intervertebral, 7, 117 knee, 153, 157f injuries, 157 lower limb, 153–155 manubriosternal, 7 metacarpophalangeal, 194 metatarsophalangeal, 155 pelvis, 82–83 pubic symphysis, 79, 83 radiocarpal, 194 radioulnar, 193 sacroiliac, 82 sacrotuberous, 82 scapulothoracic, 193 shoulder, 192–193 sternoclavicular, 7, 192 superior tibiofibular, 154 talocalcaneal, 155 talocrural, 154 tarsometatarsal, 155 temporomandibular, 220, 221 lateral ligament, 221 thoracic wall, 7–8 tibiofibular syndesmosis, 154 uncovertebral, 117 upper limb, 192–194 xiphisternal, 7 zygapophysial, 117

267

Kidney(s), 69–70 longitudinal section, 71f major calyces, 70 minor calyces, 70 pararenal fat, 70 perirenal fat, 70 renal capsule, 70 cortex, 70 fascia, 70 hilum, 70 medulla, 70 papilla, 70 pelvis, 70 pyramid, 70 sinus, 70 stones, 72 transplantation, 72 urogram of, 71f Large intestine, 54–55 anal canal, 55 sphincters, 56 appendix, 54 barium radiograph, anteroposterior, 56f cecum, 54 colon, 54 haustra, 55 McBurney’s point, 56 omental appendices, 55 pectinate line, 56 rectum, 55 teniae coli, 55, 57 Larynx, 250–255 arytenoid cartilages, 252 conus elasticus, 253 corniculate cartilages, 252 cricoid cartilage, 252, 254f cricothyroid ligament lateral, 253 median, 252 cricotracheal ligament, 252 cuneiform cartilages, 252 epiglottic cartilage, 252 hypoepiglottic ligament, 252 infraglottic cavity, 251 laryngeal cartilages, 250f fractures, 253 inlet, 250 prominence, 252

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268

INDEX

Larynx (continued) saccule, 251 ventricle, 251 vestibule, 250 quadrangular membrane, 253 skeleton, 252–253, 254f thyroepiglottic ligament, 252 thyrohyoid ligament lateral, 253 median, 253 thyrohyoid membrane, 252, 253 thyroid cartilage, 252, 254f horns inferior, 252 superior, 252 laminae, 252 Valsalva maneuver, 251 vocal ligament, 253 Leg, 137–142. See also Lower limb compartment syndrome, 140 gastrocnemius strain, 140 plantarflexion, 141 shin splints, 140 Liver, 46f anatomic lobes, 59 caudate, 59 left, 59 right, 59 quadrate, 59 anterior view, 60f bare area of, 45, 59 cirrhosis, 60 extrahepatic duct system, 63 falciform ligament, 45, 46f, 60f functional divisions, 60 Glisson’s capsule, 58 hepatic ducts, 60f right/left, 59 common, 163 hepatic lobules, 58 peritoneum and, 45 porta hepatis, 59 portal hypertension, 61 portal triads, 58 round ligament, 60f sagittal fissure left, 59 right, 59 structure, 58–59 Lower limb, 128f, 131f adductor canal, 147 areas, 146–147

compartment syndrome, 152 cribriform fascia, 151 crural fascia, 151 extensor retinacula, 151 falciform margin, 151 fascia lata, 150 fascia/connective tissue, 150–151 femoral canal, 151 ring, 148 sheath, 151 triangle, 146, 147, 148, 148f iliotibial tract, 150 joints, 153–155 plantar aponeurosis, 151 plantar fascia, 151 popliteal fascia, 151 fossa, 147 saphenous opening, 151 superficial structures, 149–150 Lung(s), 30 cardiac notch, 30 fissures, horizontal/oblique, 30 hilum of, 30 left, 30 lingula, 30 right, 30 root of, 30 Lymphatics abdominal, 74–76 lymph nodes, 11 wall, 74 axillary lymph nodes, 11 breast, 11 bronchopulmonary lymph nodes, 32 cervical, deep, 213 cisterna chyli, 76 esophagus, 74 gall bladder, 76 head, 213 infraclavicular lymph nodes, 11 jugular angle, 17 jugular lymphatic trunk, 213 jugulodigastric node, 248 kidney, 76 large intestine, 75 larynx, 248

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INDEX lingual tonsils, 213 liver, 76 lower limb, 149 lungs, 32 lymphatic duct, right, 17, 76 lymphatic plexus, deep, 32 neck, 247–248 ovaries, 91 palatine tonsils, 213, 256 pancreas, 76 parasternal lymph nodes, 11 parathyroid, 248 pelvis, 90–91 penis, 91, 109 pharyngeal tonsils, 213, 256 pharynx, 248 prostate, 91 pulmonary lymph nodes, 32 seminal glands, 91 small intestine, 75 spleen, 75 stomach, 74 subareolar lymphatic plexus, 11 subclavian lymphatic trunk, 11 superficial lymphatic plexus, 32 supraclavicular lymph nodes, 11 suprarenal glands, 76 thoracic duct, 14, 17 thyroid, 248 tracheobronchial lymph nodes, superior/inferior, 32 tubal tonsils, 213, 256 upper limb, 185 ureters, 76, 91 urethrae, 91 urinary bladder, 90 uterus, 91 vagina, 91 Waldeyer’s Ring, 213 Mediastinum, 18–26 Mouth. See Oral region Muscle(s) abdominal wall cremaster, 37, 42 dartos, 37, 42 external oblique, 37 iliacus, 38 internal oblique, 37 psoas major, 38 psoas minor, 37

269

pyramidalis, 37 quadratus lumborum, 38 rectus abdominis, 37 transverse abdominal, 37 arm, 169–170 anconeus, 170 biceps brachii, 169 brachialis, 169 coracobrachialis, 169 tendonitis of biceps brachii, 170 triceps brachii, 170 back, 122–124 deep layer, 123–124 extrinsic, 122 iliocostalis, 122 inferior oblique of the head, 125 intermediate layer, 122–123 interspinales, 123 intertransversarii, 124 intrinsic, 122–124 levator costarum, 124 longissimus, 122 multifidus, 123 rectus capitis posterior major, 125 rectus capitis posterior minor, 125 rotators, 123 semispinalis, 123 spinalis, 123 splenius, 122 suboccipital triangle, 124–125 superficial layer, 122 superior oblique of the head, 125 face, 210–212 buccinator, 211 corrugator supercilii, 211 depressor anguli oris, 212 depressor labii inferioris, 211 levator anguli oris, 211 levator labii superioris, 211 levator labii superioris alaeque nasii, 211 mentalis, 212 nasalis, 211 occipitofrontalis, 210 orbicularis oculi, 211

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270

INDEX

Muscle(s) (continued) orbicularis oris, 211 platysma, 212 procerus, 211 risorius, 212 zygomaticus major, 211 minor, 211 foot, 143–144 abductor digiti minimi, 144 abductor hallucis, 144 adductor hallucis, 144 dorsal interossei, 144 dorsum, 143 extensor digitorum brevis, 143, 145 extensor hallucis brevis, 144 flexor digiti minimi brevis, 144 flexor digitorum brevis, 144 flexor hallucis brevis, 144 lumbricals, 144 plantar interossei, 144 plantar surface, 144 quadratus plantae, 144 forearm, 174–175 abductor pollicis longus, 175 brachioradialis, 174 extensor carpi radialis brevis, 175 extensor carpi radialis longus, 174 extensor carpi ulnaris, 175 extensor digiti minimi, 175 extensor digitorum, 175 extensor indicis, 175 extensor pollicis brevis, 175 extensor pollicis longus, 175 flexor carpi radialis, 174 flexor carpi ulnaris, 174 flexor digitorum profundus, 174 flexor digitorum superficialis, 174 flexor pollicis longus, 174 palmaris longus, 174 pronator quadratus, 174

pronator teres, 174 supinator, 175 gluteal region, 129 gluteus maximus, 129 medius, 129 minimus, 129 inferior gemellus, 129 obturator internus, 129 piriformis, 129 quadratus femoris, 129 superior gemellus, 129 tensor of fascia lata, 129 hand, 180–181 abductor digiti minimi, 181 abductor pollicis, 180 adductor pollicis, 180 dorsal interossei, 181 flexor digiti minimi, 181 flexor pollicis brevis, 180 hypothenar, 181 lumbricals, 181 opponens digiti minimi, 181 opponens pollicis, 180 palmar interossei, 181 thenar, 180–181 head eyeball muscles, 233f facial expression, 203 mastication, 203 larynx, 253, 254–255 cricothyroid, 254 cricopharyngeus, 48 lateral cricoarytenoid, 255 oblique arytenoid, 255 posterior cricoarytenoid, 255 thyroarytenoid, 255 transverse arytenoid, 255 vocalis, 254 leg, 139–140 anterior compartment, 139 extensor digitorum longus, 139 extensor hallucis longus, 139 fibularis brevis, 139 longus, 139 tertius, 139

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INDEX flexor digitorum longus, 140 gastrocnemius, 139, 140 lateral compartment, 139 plantaris, 139 popliteus, 139 posterior compartment, 139 soleus, 139 tibialis anterior, 139 triceps surae, 140 levator ani, 86 tendinous arch of, 86 neck, 244 anterior scalene, 244 digastric, 244 geniohyoid, 244 infrahyoids, 244 longus capitis, 244 longus coli, 244 middle scalene, 244 mylohyoid, 244 omohyoid, 244 posterior scalene, 244 prevertebral, 244 rectus capitis, 244 sternocleidomastoid, 244 sternohyoid, 244 sternothyroid, 244 stylohyoid, 244 suprahyoids, 244 thyrohyoid, 244 torticollis, 245 oral region lateral pterygoid, 223 masseter, 223 mastication, 223 medial pterygoid, 223 temporalis, 223 orbit, 232 inferior oblique, 232 inferior rectus, 232 levator palpebrae superioris, 232 medial rectus, 232 superior oblique, 232 superior rectus, 232 superior tarsal, 232 palate, 224 levator palati, 224 musculus uvulae, 224 palatoglossus, 224 palatopharyngeus, 224 tensor palati, 224

271

papillary, 20, 22f pectinate, 19 pelvis, 85 coccygeus, 85 iliococcygeus, 85 levator ani, 85 obturator internus, 85 piriformis, 85 pubococcygeus, 85 puborectalis, 85 perineum, 112 bulbospongiosus, 112 deep transverse perineal, 112 external anal sphincter, 112 external urethral sphincter, 106, 112 ischiocavernosus, 112 superficial transverse perineal, 112 pharynx, 257–258, 259 constrictor, 259 inferior, 257 middle, 257 superior, 257 palatopharyngeus, 258 salpingopharyngeus, 256, 258 stylopharyngeus, 258 piriformis, 86 shoulder, 162–164 deltoid, 164, 165 infraspinatus, 164 latissimus dorsi, 163 levator scapulae, 163 pectoralis major, 162 pectoralis minor, 163 rhomboids, 163–164 serratus anterior, 163 paralysis, 164 subclavius, 163 subscapularis, 164 supraspinatus, 164 teres major, 164 teres minor, 164 trapezius, 163 teniae coli, 55, 57 thigh, 133–134 adductor brevis, 134 longus, 134 magnus, 134, 135

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272

INDEX

Muscle(s) (continued) anterior compartment, 133 biceps femoris, 134 cramp, 135 gracilis, 134, 135 groin pull, 135 hamstrings, 135 iliacus, 133 medial compartment, 134 obturator externus, 134 pectineus, 133 pes anserinus, 135 posterior compartment, 134 psoas major, 133 psoas minor, 133 quadriceps femoris, 135 rectus femoris, 133 sartorius, 133 semimembranosus, 134 semitendinosus, 134 vastus intermedius, 133 lateralis, 133 medialis, 133 thoracic wall, 3–4 diaphragm, 4 holes in, 5f intercostal external, 3 innermost, 3 internal, 3 levator costarum, 4 proximal attachment, 4 serratus posterior inferior, 4 superior, 4 subcostal, 3 transverse thoracic, 3 tongue, 223–224 extrinsic, 223–224 genioglossus, 223 hyoglossus, 223 intrinsic, 224 palatoglossus, 224 styloglossus, 224 Neck alimentary structures, 255–259 axillary sheath, 238 carotid sheath, 238 cervical region anterior, 240–241

lateral, 241–242 posterior, 241 superficial, 238 endocrine organs, 249–250 fascia, 237, 238, 239 deep cervical, 238 investing, 238 pretracheal, 238 prevertebral, 238 goiter, 249 hyoid, fracture, 237 parathyroid, 249 respiratory structures, 250–255 root, 245–246 skeleton, 237 spaces, 237, 238 retropharyngeal, 238 thyroid, 249 tonsillectomy, 248 veins, 240, 242, 245, 246, 247 Waldeyer’s Ring, 248 Nerve(s) abdominal wall, 39–40 femoral, 40 genitofemoral, 40 iliohypogastric, 40 ilioinguinal, 40 lateral cutaneous nerve of the thigh, 40 lumbar plexus, 39 lumbosacral trunk, 40 obturator, 40 subcostal, 39 thoracoabdominals, 39 arm, 170–171 axillary, 171 dorsal scapular, 170 lateral cutaneous, 186 lateral pectoral, 171 long thoracic, 170 lower subscapular, 171 medial cutaneous, 186 medial pectoral, 171 median, 171 musculocutaneous, 171 radial, 171 to subclavius, 170 suprascapular, 170 thoracodorsal, 171 thoracodorsal injury, 171 ulnar, 171 upper subscapular, 171 brachial plexus, 188–189 diagram, 190f

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INDEX divisions, 189 inferior trunk, 189 lateral cord, 189 medial cord, 189 middle trunk, 189 posterior cord, 189 roots, 188 superior trunk, 189 breast, 10 anterior cutaneous branch, 10 lateral cutaneous branch, 10 cranial, 203, 204f abducens, 203 facial, 203, 204 buccal branches, 214 cervical branches, 214 chorda tympani, 227 mandibular branches, 214 temporal branches, 214 zygomatic branches, 214 glossopharyngeal, 203 hypoglossal, 203 oculomotor, 203 olfactory, 203 optic, 203 spinal accessory, 203 trigeminal, 203, 204 trochlear, 203 vagus, 203 vestibulocochlear, 203 esophageal plexus, 48 esophagus, 48 face, 213–214 auriculotemporal, 214 buccal, 214 cervical spinal, 214 external nasal, 214 great auricular, 214 infraorbital, 214 infratrochlear, 214 lacrimal, 214 lesser auricular, 214 mandibular, 214 mental, 214 ophthalmic branches, 213–214 supraorbital, 213 supratrochlear, 213

273

zygomaticofacial, 214 zygomaticotemporal, 214 foot, 145 calcaneal, 145 deep fibular, 145 lateral plantar, 145 medial plantar, 145 medial sural cutaneous, 145 saphenous, 145 superficial fibular, 145 sural, 145 forearm, 176–177 anterior interosseous, 176 deep branch radial, 176 lateral cutaneous, 177, 186 medial cutaneous, 177 median, 176 posterior cutaneous, 176, 186 posterior interosseous, 176 radial, 176 ulnar, 176 gallbladder, 65 genitalia, female, 96, 97, 98, 99, 100 genitalia, male, 41, 102, 103, 104, 106 anterior scrotal, 41 genital branch of genitofemoral, 41, 42 perineal branches of posterior femoral cutaneous, 41 gluteal region, 130 clunial inferior, 130 middle, 130 superior, 130 gluteal inferior, 130 superior, 130 iliohypogastric, 130 to obturator internus, 130 posterior femoral cutaneous, 130 pudendal, 130 to quadratus femoris, 130 sciatic, 130 hand, 182 median, 182 ulnar, 182 heart, 23–24 atrioventricular bundle, 24

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274

INDEX

Nerve(s) (continued) atrioventricular nodes, 24 deep cardiac plexus, 24 right/left bundle branches, 24 sinuatrial nodes, 24 superficial cardiac plexus, 23 visceral afferents of cardiac plexus, 24 kidneys, 73 large intestine, 58 inferior rectal, 58 larynx, 255 leg, 141 common fibular, 141 deep fibular, 141 lateral sural cutaneous, 141 medial sural cutaneous, 141 posterior femoral cutaneous, 141 saphenous, 141 superficial fibular, 141 sural, 141 tibial, 141 liver, 61 lower limb, 149–150, 152 common fibular, 152 deep fibular, 150 femoral, 149, 152 genitofemoral, 149 iliohypogastric, 149 ilioinguinal, 149 inferior gluteal, 153 lateral plantar, 150 lateral sural cutaneous, 149 medial plantar, 150 medial sural cutaneous, 149 obturator, 149 saphenous, 149 subcostal, 149 superficial fibular, 150 superior gluteal, 152 sural, 149 tibial, 150 lungs, 31 neck, 240, 245 ansa cervicalis, 245 brachial plexus, 241 cervical plexus, 241 hypoglossal distribution, 246f

left recurrent laryngeal, 245 nerve point, 241 phrenic, 245 right recurrent laryngeal, 245 spinal accessory, 241 suprascapular, 241 sympathetic ganglia, 247 sympathetic trunks, 245, 247 vagus, 245 orbit, 235 ciliary ganglion, 235 ethmoidal, 235 frontal, 235 lacrimal, 235 long ciliary, 235 nasociliary, 235 short ciliary, 235 pancreas, 68 pelvis, 86–87 inferior gluteal, 86 to levator ani, 87 to obturator internus, 87 to piriformis, 87 posterior femoral cutaneous, 87 pudendal, 86 to quadratus femoris, 87 sacral plexus, 86, 88 sciatic, 86 superior gluteal, 86 perineum pudendal, 110 pharynx, 258f, 259 posterior mediastinum, 13 pterygopalatine fossa, 218 deep petrosal, 218 greater petrosal, 218 maxillary, 218 pterygoid canal, 218 pterygopalatine ganglion, 218 sacral plexus, 86 shoulder, 164, 165 axillary, 165 dorsal scapular, 165 long thoracic, 164, 165 spinal accessory, 165 supraclavicular, 165 small intestine, 53–54 spinal cord, 118–119 spleen, 69 stomach, 51

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INDEX superior mediastinum left phrenic, 16 left recurrent laryngeal, 16 left vagus, 16 right phrenic, 16 right recurrent laryngeal, 16 right vagus, 16 suprarenal glands, 74 temporal region, 215, 217 auriculotemporal, 217 buccal, 217 inferior alveolar, 217 lingual, 217 mandibular, 215, 217 to mylohyoid, 217 otic ganglion, 217 thigh, 135–136 femoral, 135 genitofemoral, 136 lateral cutaneous, 149 lateral femoral cutaneous, 136 obturator, 135 posterior cutaneous, 150 posterior femoral cutaneous, 136 sciatic, 136 thoracic wall intercostal, 6 phrenic nerve injury, 5f rami communicantes, 6 subcostal, 6 sympathetic trunk, 6 thoracic splanchnic, 6 upper limb, 186 brachial branches variations, 191 brachial cord variations, 191 brachial division variations, 191 brachial plexus variations, 191 inferior lateral cutaneous, 186 intercostobrachial, 186 medial cutaneous, 186 median nerve injury, 191 musculocutaneous nerve injury, 191 pectoral, 190 radial nerve injury, 191

275

supraclavicular, 186 terminal branches injury, 191 terminal branches of median, 186 terminal branches of radial, 186 terminal branches of ulnar, 186 ulnar nerve injury, 191 ureters, 73 urethrae, 95 urinary bladder, 93 Nose, 225–226 bloody, 226 choanae, 225 deviated septum, 226 external, 225 Kiesselbach’s area, 226 lateral walls, 225 meatuses, 225, 226 nares, 225 nasal cavities, 225 conchae, 225 septum, 225, 226 paranasal sinuses, 226 sphenoethmoidal recess, 225, 226 Oral region, 219–225 cheeks, 219 dental arches, 219 gingivae, 219 lingual frenulum, 220 lips, 219 oral cavity proper, 219 fissure, 219 vestibule, 219 palate, 220 palatine aponeurosis, 220 parotid duct, 222 glands, 222 sheath, 222 pharynx laryngopharynx, 221f nasopharynx, 221f oropharynx, 221f philtrum, 219 salivary glands, 222

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276

INDEX

Oral region (continued) sialography, 223 sphenomandibular ligament, 221 stylomandibular ligament, 221 sublingual ducts, 222 glands, 222 papilla, 222 submandibular duct, 222 ganglion, 222 glands, 222 teeth, 219 tongue foramen cecum, 220 midline groove, 220 terminal groove, 220 tongue tie, 222 uvula, 220 Orbit, 229–230 blowout fracture, 231 bulbar conjunctiva, 230 common tendinous ring, 234 conjunctivitis, 230, 232 exophthalmos, 231 eye, 229–230 choroid, 229 ciliary body, 229 ciliary process, 229 cornea, 229 fovea centralis, 230 iris, 230 macula lutea, 230 movements, 233f, 234 optic disk, 230 ora serrata, 230 sclera, 229 suspensory ligament, 234 eyelids, 228–230 lacrimal papilla, 229 puncta, 229 medial canthus, 230 orbital septum, 229 palpebrae, 229 palpebral conjunctiva, 230 ligament, 229 tarsal glands, 229 tarsal plates, 229 fascial sheath, 234 lacrimal apparatus, 230

canaliculi, 230 caruncle, 230 ducts, 230 glands, 230 lake, 230 sac, 230 lateral check ligament, 234 retina, 231f Ovaries, 98 broad ligament, 98 ligament of, 98 mesovarium ligament, 98 pampiniform plexus, 98 suspensory ligament, 98 vulva, 91 Pancreas, 46f, 66 accessory pancreatic duct, 66 body, 66 cancer, 67 head of, 60f, 66 hepatopancreatic ampulla, 66 main pancreatic duct, 66 major duodenal papilla, 66 minor duodenal papilla, 66 neck, 66 pancreatic duct sphincter, 66 tail, 66 uncinate process, 66 Pelvis anorectal junction, 85 area, 77–78 connective tissue, 84–85 fascia, 84–85 endopelvic, 84 parietal layer, 84 prostatic sheath, 85 puboprostatic ligament, 84 pubovesical ligament, 84 rectovesical septum, 85 tendinous arch, 84 visceral layer, 84 female, 101f radiograph, 101f greater, 78 greater sciatic foramen, 79, 81 ischiopubic ramus, 81 lesser, 78 lesser sciatic foramen, 79 male, midsagittal, 108f obturator canal, 79

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INDEX fascia, 86 foramen, 79 pelvic diaphragm, 86 floor trauma, 86 girdle, 78 inlet, 77 peritoneum of, 83–84 pregnancy and, 78 rectouterine pouch, 83, 84 retropubic space, 78 retrorectal space, 78 sacrospinous ligament, 81, 83 sex differences, 82 supravesical fossa, 83, 84 transverse acetabular ligament, 79 transverse cervical ligament, 85 vesicouterine pouch, 83 Penile urethra, 106 bulbourethral glands, 106 external urethral sphincter, 106 membranous urethra, 106 urethral glands, 106 Penis, 107, 108 body, 108 corona, 109 corpora cavernosa, 107 corpus spongiosum, 107 deep fascia, 107 ejaculation, 109 erection, 109 fundiform ligament, 109 glans, 109 prepuce, 109 root, 108 suspensory ligament, 109 Pericardial cavity, 18 fibrous pericardium, 18 oblique sinus, 18 parietal layer of serous pericardium, 18 pericarditis, 19 pericardium, 18 sac, 18 tamponade, 19 transverse sinus, 18 visceral layer of serous pericardium, 18

277

Perineum anal triangle, 110 area, 110 deep perineal pouch, 110 episiotomy, 111 fascia/connective tissue, 111 ischioanal fossae, 110 perineal body, 111 perineal membrane, 111 pudendal canal, 110 superficial fascia, membranous layer, 111 superficial perineal pouch, 110, 111 urogenital triangle, 110 Peritoneal cavity, 42–44 ascending colon, 46f colic flexure left, 46f right, 46f descending colon, 46f greater omentum, 46f greater sac, 43 hepatorenal recess, 43 inferior epigastric vessels, 45 inferior recess of omental bursa, 46f infracolic compartment, 43 infracolic spaces, 46f lesser omentum, 46f lesser sac, 43 inferior recess of, 43 superior recess of, 43 ligament(s) coronary, 45 falciform, 45, 46f, 60f gastrocolic, 45 gastrophrenic, 45 gastrosplenic, 45 hepatoduodenal, 45 hepatogastric, 45 medial umbilical, 47 median umbilical, 47 medial inguinal fossa, 47 mesentery, 46f omental bursa, 43 omental foramen, 43 paracolic gutters, 43, 46f parietal peritoneum, 46f peritoneal folds lateral umbilical, 45 medial umbilical, 44 median umbilical, 44

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278

INDEX

Peritoneal cavity (continued) peritoneal fossae lateral inguinal, 44 medial inguinal, 44 supravesical, 44 peritoneal relations, 47 phrenicocolic ligament, 46f rectovesical pouch, 46f rectum, 46f, 55 subdivisions of, 46f subhepatic space, 46f subphrenic spaces, 43 supracolic compartment, 43, 46f tenia coli, 46f transverse colon, 46f transverse mesocolon, 46f triangular ligaments, 45 urachus, 47 urinary bladder, 46f visceral peritoneum, 46f Peritoneum, 44–45 greater omenta, 45 lesser omenta, 45 liver and, 45 mesentery, 44 parietal peritoneum, 44 peritoneal folds, 44 portal triad, 45 round ligament of liver, 45 visceral peritoneum, 44 Pharynx, 256 auditory tube, 256 fascia, 258 pharyngobasilar, 256, 258 piriform fossa, 257 piriform recess, 256 salpingopharyngeal fold, 256 salpingopharyngeus, 256 swallowing, 257 tonsillar bed, 256 Pleural cavities, 26–27 cervical pleura, 26, 28 costal pleura, 26 costodiaphragmatic recesses, right/left, 27 costomediastinal recess, right/left, 27 diaphragmatic pleura, 26

endothoracic fascia, 26 mediastinal pleura, 26 pneumothorax, 28f pulmonary ligament, 26 visceral pleura, 27 Posterior mediastinum, 13–14 Prostate, 102–104, 105f enlargement, 105f, 106 Ribs, 1, 3 Scrotum, 37 Seminal glands, 102–103 Shoulder, 157–167 radiograph, 162f rotator cuff, 165 Small intestine, 51–52 duodenojejunal junction, 52 duodenum, 46f, 51, 60f ileocecal junction, 52 ileum, 52 jejunum, 52 Spermatic cord, 37, 41–42 autonomics of, 42 ductus deferens, 42 fascial coverings, 41 sensory innervation, 41 Spinal cord cauda equina, 118 cervical enlargement, 118 dural sac, 118 epidural anesthesia, 121 gray matter, 119 lumbar cistern, 118 enlargement, 118 puncture, 122 lumbosacral plexus, 118 medullary cone, 118 meninges, 120–121 arachnoid mater, 120, 121 arachnoid trabeculae, 121 denticulate ligaments, 121 dura mater, 120 dural root sheaths, 120 dural sac, 120, 121 epidural space, 120 filum terminale, 121 lumbar cistern, 121 pia mater, 120, 121 subarachnoid space, 121 subdural space, 121

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INDEX rami, anterior/posterior, 119 roots, anterior/posterior, 119 spinal block, 122 spinal ganglion, 119 white matter, 119 Spleen, 60f, 68 gastrosplenic ligament, 68 hilum, 68 splenomegaly, 68 splenorenal ligament, 68 Stomach, 46f, 49, 60f angular incisure, 49 body, 49 cardia, 49 cardial orifice, 49 fundus, 49 greater curvature, 49 lesser curvature, 49 pyloric antrum, 49 pyloric canal, 49 pyloric orifice, 49 pyloric sphincter, 49 pylorospasm, 50 pylorus, 49 rugae, 49 Superior mediastinum, 16–17 Suprarenal glands, 73 cortex, 73 medulla, 73 Testes, 105f, 106–107 pampiniform plexus, 107 tunica vaginalis, 106 Thigh, 132–137 bones, 132 coxa valga, 133 coxa vara, 133 femur, 132 fracture, 133 Thoracic cavity, 11, 12 anterior mediastinum, 12 inferior mediastinum, 12 inferior thoracic aperture, 12 intercostal space, 12 middle mediastinum, 12 posterior mediastinum, 12 superior mediastinum, 12 superior thoracic aperture, 12 thoracic outlet syndrome, 13 Thoracic wall, 1–8 intercostal nerve block, 4f sternal puncture, 3 thoracocentesis, 4f

279

Thorax anteroposterior chest radiograph, 27f Thymus, 16 Trachea, 16 cartilages, 254f glottis, 251 rima glottidis, 251 rima vestibuli, 251 vestibular folds, 251 vocal folds, 251, 253 Tracheobronchial tree, 28–29 bronchopulmonary segments, 29 carina, 29 lobar bronchi, right, 29 left, 29 main bronchi, right/left, 29 segmental bronchi, 29 tracheal rings, 28 trachealis, 29 Upper limb, 185–186 anatomic snuff-box, 184 areas, 183–184 arteries, 161f axilla, 183–184 axilla wounds, 185 bones, 160f carpal tunnel, 184 syndrome, 185 cubital fossa, 184 deltopectoral triangle, 184 dermatome maps, 187f fascia/connective tissue, 188 antebrachial, 188 axillary, 188 brachial, 188 clavipectoral, 188 costocoracoid membrane, 188 deltoid, 188 extensor retinaculum, 188 flexor retinaculum, 188 palmar, 188 pectoral, 188 superficial transverse carpal ligament, 188 suspensory ligament of the axilla, 188 lower triangular space, 184 quadrangular space, 184 upper triangular space, 184

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280

INDEX

Ureters, 72 Urethrae, 94 catheterization, 94 female, 94 male, 94 Urinary bladder, 46f, 91–92 apex, 92 body, 91 detrusor muscle, 92 fundus, 92 internal urethral orifice, 92 sphincter, 92 lymphatics, 90 median umbilical fold, 92 neck, 92 peritoneal relations, 92 urinary trigone, 92 Uterine tubes, 97 Uterus, 97 Vagina, 95, 96 Vein(s) abdominal wall, 39 arm, 172 azygos, 14 basilic, 185 brachiocephalic left, 17, 22f right, 17, 22f brain, 209 breast, 10 bronchial, right/left, 32 bulbourethral glands, 104 cardiac anterior, 25 great, 25 middle, 25 small, 25 smallest, 25 cephalic, 185 clitoris, 100 coronary sinus, 25 cubital, median, 185, 186 ductus deferens, 102 ejaculatory ducts, 103 esophagus, 48 face, 213 female genitalia external, 99 internal, 96 foot, 146 forearm, 177 median, 185

gallbladder, 65 gastric left, 50 right, 50 gastro-omental left, 50 right, 50 genitalia, female, 96, 97, 98, 99, 100 genitalia, male, 102, 103, 104, 106 gluteal region, 132 gonadal, 72 hand, 183 hemiazygos, 14 accessory, 14 hepatic, 61 inferior epigastric vessels, 45 jugular anterior, 240 external, 242 internal, 240 jugular venous arch, 246 large intestine, 57 larynx, 251 leg, 142 lingual, deep, 222 lower limb, 149 lungs, 31–32 marginal, left, 25 medullary, 120 mesenteric inferior, 60f superior, 60f, 62f neck, 240, 242, 245, 246, 247 oblique vein of left atrium, 25 ophthalmic inferior, 235 superior, 235 orbit, 235 ovaries, 98 pampiniform plexus, 39, 42 pancreas, 67 pelvis, 89 penile urethra, 106 penis, 107 perforating, 149 portal, 60f, 61, 62f left branches, 60f right branches, 60f prostate, 104 pterygoid venous plexus, 216 pudendal, 110 pulmonary, right/left, 31

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INDEX radicular, 120 renal, 72 retina, central, 235 saphenous great, 149, 150 small, 149 scleral venous sinus, 235 seminal glands, 102 short, 50 small intestine, 53 spinal anterior, 120 posterior, 120 spinal cord, 120 splenic, 60f, 62f, 69 stomach, 50 subclavian, 240, 242, 247 suprarenal left, 74 right, 74 temporal region, 216 testes, 107 thigh, 137 thoracic wall, 6 upper limb, 185 urethrae, 95 urinary bladder, 93 uterine tubes, 97 uterus, 96 vagina, 96 vena cava inferior, 22f superior, 17 venous angle, 246 venous arch, dorsal, 149 venous network, dorsal, 185 ventricular, left posterior, 25 vertebral venous plexus, internal, 120 vestibule bulbs, 100 vorticose, 235 Vertebrae column, 113, 114–115 alar ligaments, 117

281

anulus fibrosis, 117 appendicular skeleton, 113 atlanto-occipital membranes, anterior/posterior, 117 axial skeleton, 113 cervical, 115 coccygeal, 115 cruciform ligament, 117 curvatures, 113, 114f cervical, 113 excess, 114 lumbar, 113 sacral, 113 thoracic, 113 diagram, 116f interspinous ligament, 118 intertransverse ligaments, 118 intervertebral discs, 117 intervertebral foramina, 115 kyphosis, 114, 114f ligamentum flavum, 117 ligamentum nuchae, 118 longitudinal bands, 117 longitudinal ligaments, anterior/ posterior, 117 lordosis, 114, 114f lumbar, 115 nucleus pulposus, 117 ruptured disc, 118 sacral, 115 scoliosis, 114, 114f slipped disc, 118 spina bifida, 116 supraspinous ligament, 118 tectorial membrane, 117 thoracic, 115 transverse ligament of the atlas, 117 vertebra prominens, 115 Vestibular glands, 100 Vestibule bulbs, 100 Vulva, ovaries, 91

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