MDCT Anatomy - Body

MDCT Anatomy – Body

Luigia Romano · Massimo Silva · Sonia Fulciniti · Antonio Pinto (Eds.)

MDCT Anatomy – Body Foreword by Giuseppe Brancato

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L. Romano et al. Editors Luigia Romano, MD Director of Diagnostic Imaging Department Cardarelli Hospital Naples, Italy

Sonia Fulciniti, MRT Diagnostic Imaging Department Cardarelli Hospital Naples, Italy

Massimo Silva, MRT Diagnostic Imaging Department Cardarelli Hospital Naples, Italy

Antonio Pinto, MD Diagnostic Imaging Department Cardarelli Hospital Naples, Italy

The contents of this book are based on: Anatomia TC multidetettore – Body. L. Romano, M. Silva, S. Fulciniti (Eds.) © Springer-Verlag Italia 2010

ISBN 978-88-470-1877-8

e-ISBN 978-88-470-1878-5

DOI 10.1007/978-88-470-1878-5

Springer Milan Dordrecht Heidelberg London New York Library of Congress Control Number: 2010939862 © Springer-Verlag Italia 2011 This work is subject to copyright. All rights are reserved, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilm or in any other way, and storage in data banks. Duplication of this publication or parts thereof is permitted only under the provisions of the Italian Copyright Law in its current version, and permission for use must always be obtained from Springer. Violations are liable to prosecution under the Italian Copyright Law. The use of general descriptive names, registered names, trademarks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. Product liability: The publishers cannot guarantee the accuracy of any information about dosage and application contained in this book. In every individual case the user must check such information by consulting the relevant literature. 9 8 7 6 5 4 3 2 1 Cover design: Ikona S.r.l., Milano Typesetting: C & G di Cerri e Galassi, Cremona Printing and binding: Printer Trento S.r.l., Trento Printed in Italy Springer-Verlag Italia S.r.l., Via Decembrio 28, I-20137 Milano Springer is part of Springer Science+Business Media (www.springer.com)

Foreword

My initial curiosity upon receiving this atlas was quickly satisfied: the images and accompanying text clearly reflect the professionalism of the authors, who with MDCT Anatomy - Body have produced a very important book. The detailed MDCT images were carefully chosen, guided by the authors’ extensive knowledge and experience. The authors have chosen a highly methodical approach to human MDCT anatomy, as evidenced by their selection of images, the clarity of the accompanying legends, and their presentation of the various anatomical correlations. The resulting volume is a very useful reference, combining clinical aspects with technical applications. It will be appreciated not only by residents and technologists but by students as well. For these reasons, it is an honor for me to recommend this book, and I am very grateful to the authors for their time and efforts spent in its realization. Florence, November 2010

Giuseppe Brancato Director Technical Health University Hospital Meyer Florence, Italy President of the Italian Federation of Radiology Technologists (TSRM)

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Preface

Multidetector CT (MDCT), or multidetector-row CT, multislice CT, or volume CT, as it is also called, represents the next breakthrough in computed tomography technology. The MDCT body atlas is a useful reference for radiology technologists, familiarizing them with state-of-the-art MDCT imaging of the thorax, abdomen, and pelvis. Since its introduction in 1990, MDCT has been of enormous clinical advantage, resolving diagnostic challenges that could not be adequately addressed with the images generated by a spiral single-slice machine. The increasing slice capability, from 4 (8, 16, 32) to 64 slices, has tremendously improved imaging resolution. Moreover, acquisition speeds are now fast enough such that many slices can be acquired within a single tube rotation, allowing three anatomical regions to be studied within one imaging session. This enormous increase in performance has been realized in shorter scan durations, longer scan ranges, and thinner sections. MDCT also enhances the contrast power, with the possibility to study anatomical regions in several vascular phases. During the arterial phase of a multiphase study, only the arterial vessels opacify, with a resolution comparable to that achieved with arteriography. Enhancement of the parenchyma, bowel wall, and portal vessels occurs during the portal phase, while during the equilibrium or late capillary phase, venous structures are maximally enhanced, revealing the superior and inferior caval systems. Bi- and tridimensional reconstructions with a very small collimation (< 1 cm) and the same resolution as obtained with axial images are another advantage of MDCT. The enhancement of small anatomical structures in great detail and from different angles of view results in visualizations of very high fidelity. This atlas offers a practical and useful guide to human MDCT anatomy. To facilitate the use of this reference, the thorax, abdomen, and pelvis are presented in three separate sections; with image selection in each one based upon the best contrast phase, plane, and reconstruction. The legends accompanying the images provide a brief synthesis of the anatomical correlations among the spaces, parenchyma, vessels, and thoracic, abdominal, and pelvic structures. We extend our thanks to the authors for their excellent efforts and suggestions during the preparation of the atlas. Naples, November 2010

Luigia Romano Massimo Silva Sonia Fulciniti Antonio Pinto

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Contents

Part I

Thorax . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1

1

Lungs and Interstitial Network . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Antonio Pinto, Sonia Fulciniti, Rosa Ignarra

3

2

Airways . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Antonio Pinto, Sonia Fulciniti, Mariano Pepe

9

3

Pulmonary Arteries and Veins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Giovanna Russo, Cesare Giglio

15

4

Aorta and Supra-aortic Trunks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Amelia Sparano, Gennaro Barbato

23

5

Bronchial Arteries and Vena Cava . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Giovanna Russo, Cesare Giglio

29

6

Pleura and Pericardium . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Silvana Nicotra, Raffaella Marino

37

7

Mediastinal Compartments, Lymphatic System, and Esophagus . . . . . . . . . . . . . Natale Minervino, Francesco Varchetta, Mariano Scaglione

45

8

Heart and Coronary Arteries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Francesco Varchetta, Natale Minervino, Mariano Scaglione

53

9

Chest Wall . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Silvana Nicotra, Gennaro Barbato

61

Part II

Abdomen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

69

10

Diaphragm and Abdominal and Pelvic Walls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gianluca Ponticiello, Giuseppina Perrotta

71

11

Peritoneal Cavity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Luigia Romano, Massimo Silva, Ciro Acampora

79

ix

x

Contents 12

Splanchnic Arteries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Daniela Vecchione, Gennaro Barbato

89

13

Iliac Arteries and Abdominal Aorta . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Stefania Daniele, Paolo Iovine

95

14

Renal Arteries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Daniela Vecchione, Paolo Iovine

103

15

Inferior Vena Caval System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ciro Stavolo, Raffaella Marino

105

16

Venous Portal Circle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ciro Stavolo, Raffaella Marino

111

17

Abdominal Lymphatic System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Teresa Cinque, Anna Maria Di Costanzo

117

18

Gastroduodenal Tract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Luigia Romano, Ciro Petrella, Raffaella Niola

123

19

Small Intestine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Luigia Romano, Ciro Petrella, Maria Giuseppina Scuderi

129

20

Colon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Luigia Romano, Ciro Petrella, Loredana Di Nuzzo

135

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Liver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Nicola Gagliardi, Sonia Fulciniti, Giuseppe Ruggiero

141

22

Biliary System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Francesco Di Pietto, Rosaria De Ritis, Anna Elia

147

23

Spleen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gianluca Ponticiello, Giuseppina Perrotta

151

24

Extraperitoneal Spaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Luigia Romano, Maria Marino, Roberto Farina

155

25

Pancreas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Nicola Gagliardi, Sonia Fulciniti, Angelo Rizzo

163

26

Adrenal Glands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Antonio Pinto, Massimo Silva, Carlo Muzj

167

27

Kidneys and Ureters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Stefanella Merola, Ugo Ponticelli, Crescenzo Cacciutto

169

Contents

Part III

xi

Pelvis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

177

28

Urinary Bladder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Stefanella Merola, Ugo Ponticelli, Raffaele Mazzeo

179

29

Bony Pelvis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rosaria De Ritis, Francesco Di Pietto, Vincenzo Braun

183

30

Muscular Pelvis and Pelvic Floor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rosaria De Ritis, Francesco Di Pietto, Ciro Anatrella

187

31

Pelvic Space . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Luigia Romano, Fabio Pinto, Antonio Fusco

191

32

Female Pelvis: Uterus, Ovaries, and Ligaments . . . . . . . . . . . . . . . . . . . . . . . . . . . Rosaria De Ritis, Francesco Di Pietto, Ciro Anatrella

197

33

Prostate and Seminal Vescicles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Stefanella Merola, Paolo Iovine, Giuseppe Apolito

201

List of Authors

Ciro Acampora, MD Diagnostic Imaging Department Cardarelli Hospital Naples, Italy

Anna Maria Di Costanzo, MRT Diagnostic Imaging Department Cardarelli Hospital Naples, Italy

Giuseppe Apolito, MD Diagnostic Imaging Department Cardarelli Hospital Naples, Italy

Loredana Di Nuzzo, MD Diagnostic Imaging Department Cardarelli Hospital Naples, Italy

Ciro Anatrella, MRT Diagnostic Imaging Department Cardarelli Hospital Naples, Italy

Francesco Di Pietto, MD Diagnostic Imaging Department Cardarelli Hospital Naples, Italy

Gennaro Barbato, MRT Diagnostic Imaging Department Cardarelli Hospital Naples, Italy

Anna Elia, MRT Diagnostic Imaging Department Cardarelli Hospital Naples, Italy

Vincenzo Braun, MRT Diagnostic Imaging Department Cardarelli Hospital Naples, Italy

Roberto Farina, MD Diagnostic Imaging Department Cardarelli Hospital Naples, Italy

Crescenzo Cacciutto, MD Diagnostic Imaging Department Cardarelli Hospital Naples, Italy

Sonia Fulciniti, MRT Diagnostic Imaging Department Cardarelli Hospital Naples, Italy

Teresa Cinque, MD Diagnostic Imaging Department Cardarelli Hospital Naples, Italy

Antonio Fusco, MPN Diagnostic Imaging Department Cardarelli Hospital Naples, Italy

Stefania Daniele, MD Diagnostic Imaging Department Cardarelli Hospital Naples, Italy

Nicola Gagliardi, MD Diagnostic Imaging Department Cardarelli Hospital Naples, Italy

Rosaria De Ritis, MD Diagnostic Imaging Department Cardarelli Hospital Naples, Italy

Cesare Giglio, MRT Diagnostic Imaging Department Cardarelli Hospital Naples, Italy

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xiv

List of Authors Rosa Ignarra, MD Diagnostic Imaging Department Cardarelli Hospital Naples, Italy

Antonio Pinto, MD Diagnostic Imaging Department Cardarelli Hospital Naples, Italy

Paolo Iovine, MRT Diagnostic Imaging Department Cardarelli Hospital Naples, Italy

Fabio Pinto, MD Diagnostic Imaging Department Cardarelli Hospital Naples, Italy

Raffaella Marino, MRT Diagnostic Imaging Department Cardarelli Hospital Naples, Italy

Ugo Ponticelli, MRT Diagnostic Imaging Department Cardarelli Hospital Naples, Italy

Raffaele Mazzeo, MD Diagnostic Imaging Department Cardarelli Hospital Naples, Italy

Gianluca Ponticiello, MD Diagnostic Imaging Department Cardarelli Hospital Naples, Italy

Stefanella Merola, MD Diagnostic Imaging Department Cardarelli Hospital Naples, Italy

Angelo Rizzo, MD Diagnostic Imaging Department Cardarelli Hospital Naples, Italy

Natale Minervino, MRT Department of Diagnostic Imaging Pineta Grande Medical Center Castel Volturno (CE), Italy

Luigia Romano, MD Director of Diagnostic Imaging Department Cardarelli Hospital Naples, Italy

Carlo Muzj, MD Diagnostic Imaging Department Cardarelli Hospital Naples, Italy

Giuseppe Ruggiero, MD Diagnostic Imaging Department Cardarelli Hospital Naples, Italy

Silvana Nicotra, MD Diagnostic Imaging Department Cardarelli Hospital Naples, Italy

Giovanna Russo, MD Diagnostic Imaging Department Cardarelli Hospital Naples, Italy

Raffaella Niola, MD Diagnostic Imaging Department Cardarelli Hospital Naples, Italy

Mariano Scaglione, MD Director of Diagnostic Imaging Department Pineta Grande Medical Center Castel Volturno (CE), Italy

Mariano Pepe, MD Diagnostic Imaging Department Cardarelli Hospital Naples, Italy

Maria Giuseppina Scuderi, MD Diagnostic Imaging Department Cardarelli Hospital Naples, Italy

Giuseppina Perrotta, MRT Diagnostic Imaging Department Cardarelli Hospital Naples, Italy

Massimo Silva, MRT Diagnostic Imaging Department Cardarelli Hospital Naples, Italy

Ciro Petrella, MRT Diagnostic Imaging Department Cardarelli Hospital Naples, Italy

Amelia Sparano, MD Diagnostic Imaging Department Cardarelli Hospital Naples, Italy

List of Authors Ciro Stavolo, MD Diagnostic Imaging Department Cardarelli Hospital Naples, Italy Francesco Varchetta, MRT Department of Diagnostic Imaging Pineta Grande Medical Center Castel Volturno (CE), Italy

xv Daniela Vecchione, MD Diagnostic Imaging Department Cardarelli Hospital Naples, Italy

Part Thorax

I

Lungs and Interstitial Network

1

Antonio Pinto, Sonia Fulciniti, Rosa Ignarra

L. Romano, M. Silva, S. Fulciniti, A. Pinto (eds.) MDCT Anatomy – Body © Springer-Verlag Italia 2011

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A. Pinto et al.

Trachea Right lung

Left lung Left main bronchus

Right main bronchus

a

Right lung

Left lung Upper lobe of the left lung

Upper lobe of the right lung

Oblique fissure

Major fissure

b

Upper lobe of the left lung

Oblique fissure Minor fissure

Lower lobe of the left lung

Major fissure Lower lobe of the right lung c

Fig. 1.1 a The lungs are situated on either side of the heart and other mediastinal contents. Each lung is free in its pleural cavity, except for its attachment to the heart and trachea at the hilum and pulmonary ligament. b The presence of two fissures in the right lung and one in the left lung defines three lobes at the level of the right lung and two lobes at the level of the left lung. c The right lung is divided into upper, middle, and lower lobes by two fissures. The upper, oblique fissure (or major fissure) separates the lower lobe from the middle and upper lobes. The short horizontal fissure (or minor fissure) separates the superior and middle lobes. The left lung is divided into a superior and an inferior lobe by an oblique fissure

1 Lungs and Interstitial Network

5

Anterior segment of the right upper lobe

Left lung

Aortic arch Apical segment of the right upper lobe Oblique fissure Posterior segment of the right upper lobe a

Medial segment of the middle lobe

Left lung

Lateral segment of the middle lobe

Oblique fissure

Descending thoracic aorta

Superior segment of the right lower lobe b

Oblique fissure Anterior basal segment of the right pulmonary lower lobe Left pulmonary lower lobe

Lateral basal segment of the right pulmonary lower lobe Posterior basal segment of the right pulmonary lower lobe

Medial basal segment of the right pulmonary lower lobe c

Fig. 1.2 a There are ten pulmonary segments in the right lung. The upper lobe of the right lung comprises three segments: apical (S1), posterior (S2), and anterior (S3). b The middle lobe consists of two segments: lateral (S4) and medial (S5). c The following segments make up the right lower pulmonary lobe: superior (S6), medial basal (S7), anterior basal (S8), lateral basal (S9), and posterior basal (S10)

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A. Pinto et al.

Aortic arch

Anterior segment of the left upper lobe

Right pulmonary upper lobe

Apicoposterior segment of the left upper lobe

Trachea

Oblique fissure

a Superior segment of the lingula Ascending thoracic aorta Oblique fissure Superior segment of the left lower lobe

Descending thoracic aorta Superior segment of the right lower lobe

b Inferior segment of the lingula

Middle lobe

Anteromedial basal segment of the left lower lobe

Right lower lobe

Lateral basal segment of the left lower lobe Posterior basal segment of the left lower lobe

c

Fig. 1.3 a The following segments comprise the upper lobe of the left lung: apicoposterior (S1+S2), anterior (S3), and b superior segment of the lingula (S4). c Inferior segment of the lingula. The lower lobe of the left lung consists of the following segments: superior (S6), anteromedial basal (S7+S8), lateral basal (S9), and posterior basal (S10)

1 Lungs and Interstitial Network

7

Interlobular septa

Interlobular septa

a Interlobular septum

Interlobular septum

b

Oblique fissure Minor fissure Major fissure

c

Fig. 1.4 a, b The septa of the lungs are contiguous visceral pleural membranes that enclose each lung. The secondary lobule is the smallest discrete portion of the lung surrounded by connective tissue. It is also the smallest anatomical unit that can be clearly identified on high-resolution CT. The interlobular septa are thickest and most numerous at the apical, anterior, and lateral aspects of the upper lobes, the anterior and lateral aspects of the middle lobe, and the lingula. c Pulmonary fissures are visible as avascular bands

Airways

2

Antonio Pinto, Sonia Fulciniti, Mariano Pepe

L. Romano, M. Silva, S. Fulciniti, A. Pinto (eds.) MDCT Anatomy – Body © Springer-Verlag Italia 2011

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A. Pinto et al.

Trachea

Right lung

Left lung

Oblique fissure

a

Trachea Right lung

Left lung

Major fissure

b

Calcification of the anterior tracheal wall in an elderly individual Posterior tracheal wall

c

Fig. 2.1 a The trachea descends from the larynx, extending from the level of the sixth cervical to the upper border of the fifth thoracic vertebra. b The normal tracheal wall is relatively thin and is defined internally by the central airway. c There is marked variability in the CT appearance of the trachea. The trachea tends to be more uniformly round in children and young adults, while in the elderly it may be horse-shoe shaped. The trachea tends to be transversely ovoid near the carina. The ring cartilages may be irregularly calcified in the elderly

2 Airways

11

Trachea Right main bronchus Left main bronchus

a

Right main bronchus Right upper lobe bronchus

Bronchus intermedius

b

Left main bronchus

Left upper lobe bronchus

c

Fig. 2.2 a At the level of the fifth thoracic vertebra, the trachea divides into the right and left main bronchi. b The right main bronchus is wider, shorter, and more vertical than the left. It gives rise to its first branch, the upper lobe bronchus. c The left main bronchus is narrower and less vertical than the right. After entering the hilum, the left main bronchus divides into upper and lower lobe bronchi

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A. Pinto et al.

Right main bronchus

Apical segmental bronchus of the right upper lobe bronchus a

Right upper lobe bronchus

Anterior segmental bronchus of the right upper lobe bronchus

Posterior segmental bronchus of the right upper lobe bronchus

b

Bronchus intermedius

c

Fig. 2.3 a The right upper lobe bronchus arises from the lateral aspect of the right main bronchus and runs superolaterally to enter the hilum. b About 1 cm from its origin, it divides into three segments: the apical, posterior, and anterior segmental bronchi. c The bronchus intermedius starts approximately 2 cm below the upper bronchus and runs 3-4 cm distally, presenting an elliptical section on CT scan

2 Airways

13

Right middle lobe bronchus

Right lower lobe bronchus

a Medial segmental bronchus of the middle lobe bronchus

Lateral segmental bronchus of the middle lobe bronchus Right lower lobe bronchus

b

Anterior basal segmental bronchus of the right lower lobe bronchus Lateral basal segmental bronchus of the right lower lobe bronchus Posterior basal segmental bronchus of the right lower lobe bronchus

c

Fig. 2.4 a The bronchus intermedius terminates on CT section where the middle and right lower lobe bronchi are visible. b The middle lobe bronchus divides into lateral and medial segmental bronchi, passing to the lateral and medial parts of the middle lobe, respectively. The right lower lobe bronchus is the continuation of the main bronchus beyond the origin of the middle lobe bronchus. At or slightly below its origin from the main bronchus, it gives off a superior segmental bronchus posteriorly. c Caudally, the basal (medial, anterior, lateral, and posterior) segments arising from the right lower lobe bronchus are visible

14

A. Pinto et al. Posterior basal segmental bronchus of the left lower lobe bronchus Posterior basal segmental bronchus of the left lower lobe bronchus

a

Left upper lobe bronchus Left lower lobe bronchus

b

Superior segmental bronchus of the left lower lobe bronchus

Anteromedial segmental bronchus of the left lower lobe bronchus Lateral basal segmental bronchus of the left lower lobe bronchus

Posterior basal segmental bronchus of the left lower lobe bronchus

c Fig. 2.5 a The left upper lobe bronchus arises from the anterolateral aspect of the left main bronchus to curve laterally and soon divides into two bronchi. The superior division gives off an anterior segmental bronchus, then continues as the apicoposterior segmental bronchus. The inferior division descends anterolaterally to the anteroinferior part of the left superior lobe (the lingula) forming the lingular bronchus, which divides into superior and inferior lingular segmental bronchi. b The left lower lobe bronchus arises from the left main bronchus and then descends posterolaterally for 1 cm, posteriorly giving rise to the superior segmental bronchus. c Caudally, after a further 1-2 cm, the left lower lobe bronchus divides into anteromedial and posterolateral branches. The latter then divides into the lateral and posterior basal segmental bronchi

Pulmonary Arteries and Veins

3

Giovanna Russo, Cesare Giglio

L. Romano, M. Silva, S. Fulciniti, A. Pinto (eds.) MDCT Anatomy – Body © Springer-Verlag Italia 2011

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G. Russo, C. Giglio

Superior vena cava

Common trunk of the PA

Right upper PV Left upper PV Right main PA

Left apical-dorsal segmental bronchus a

Common trunk of the PA Right upper PV

Left upper PV

Right main PA

Left main PA

b

Right upper lobe PA

Anterior segmental PA of the left upper lobe

Right descending PA

Left descending PA

c Fig. 3.1 a Axial image taken at a plane passing through the common trunk of the pulmonary artery shows the course of the right and left upper pulmonary veins. The right upper pulmonary vein is localized in front of the horizontal section of the right main pulmonary artery; the left upper pulmonary vein is localized anteromedially with respect to the left apical-dorsal segmental bronchus of the lung’s upper lobe. b Axial maximum-intensity projection (MIP) image shows the upper pulmonary veins localized in front of the main branches of the pulmonary artery. c Axial MIP image shows the posterior course of the left descending branch of the pulmonary artery. PA, Pulmonary artery; PV, Pulmonary vein

3 Pulmonary Arteries and Veins

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Right ascending PA Apical bronchus of the right upper lobe

Left main PA

Left upper PV

Right upper PV a

Left upper lobe PA

Left main PA

Right interlobar PA Right lower PV

b

Left descending PA

c Fig. 3.2 a Coronal MIP image in a scan plane passing through the horizontal section of the right main pulmonary artery shows the anatomical relationships between the right upper lobe pulmonary artery and right upper lobe pulmonary vein with respect to the bronchi. The ascending branch of the pulmonary artery is medial to the apical and anterior segmental bronchi, and the right upper pulmonary vein lateral to them. b Coronal MIP image shows the vertical course of the right interlobar pulmonary artery with respect to the horizontal course of the right lower pulmonary vein. The left main pulmonary artery is higher than the right one. c Sagittal MIP image shows the vertical course of the left interlobar pulmonary artery

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G. Russo, C. Giglio

Common trunk of the PA

Right main PA

Left lower lobe PA

a

Left lower segmental PA

Right lower lobe PA

b

Right lower PV Right lower segmental PA

Left lower segmental PA

c

Fig. 3.3 a This axial image was taken at a plane passing through the common trunk of the pulmonary artery. The left main pulmonary artery is higher than the right. The right main pulmonary artery is lower than the right main bronchus. b The axial image shows that the branches of the pulmonary artery closely follow the course of the corresponding bronchi; the pulmonary arteries are located in a posterolateral position relative to the bronchi. c Axial image shows the horizontal course of the lower pulmonary veins with respect to the vertical course of the pulmonary arteries. The latter are located in a posterolateral position relative to the corresponding segmental bronchi of the lower lobes

3 Pulmonary Arteries and Veins

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Apical segmental PA of the RUL Apical segmental bronchus of the RUL

Tributaries of the right upper PV a

Anterior segmental bronchus of the RUL

Right upper lobe PA

Posterior segmental bronchus of the RUL

Posterior segmental PA of the RUL

b

Posterior segmental PV of the RUL

Anterior segmental of the RUL

Posterior segmental PA of the RUL

c Fig. 3.4 a Axial image of the right lung in a scan plane passing through the tracheal carina shows the normal anatomy of the segmental pulmonary arteries. The apical segmental pulmonary artery of the right upper lobe is located medial to the apical bronchus. The tributaries branches of the upper pulmonary vein are located lateral to the corresponding upper bronchus. b Axial image at the level of right upper lobe reveals the anatomical relationships between the anterior and posterior segmental bronchi and the pulmonary arterial branches. c Axial image at the level of the anterior segmental bronchus of the right upper lobe shows the posterior segmental pulmonary artery, which typically arises from the interlobar pulmonary artery. RUL, Right upper lobe

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Anterior segmental PA of the LUL

Apical-dorsal segmental PA of the LUL

a

Upper lingular bronchus Upper lingular segmental PA of the LUL

b

Lower lingular bronchus

Medial segmental PA of the ML

Lower lingular segmental PA of the LUL

Lateral segmental PA of the ML

Left lower lobe PA

c Fig. 3.5 a Axial image of the left lung at a scanning plane passing above the tracheal carina shows the anatomical relationships between the apical-dorsal and anterior segmental bronchi of the left upper lung and the corresponding segmental pulmonary arteries located medially. b The upper lingular pulmonary artery arises from the left interlobar pulmonary artery and typically runs higher than the corresponding lingular bronchus. c The axial image shows the lower lingular segmental pulmonary artery running laterally with respect to the corresponding bronchus. The image also shows the medial and lateral segmental pulmonary arteries of the middle lobe running laterally relative to the corresponding bronchial branches. LUL, Left upper lobe; ML, Middle lobe

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Medial segmental PA of the ML Lateral segmental PA of the ML

Medial bronchus of the ML

Lateral bronchus of the ML a

Right lower lobe PA Left lower lobe PA Apical bronchus of the RLL

Apical bronchus of the LLL

b

Medial basal segmental PA of the RLL Anterior-medial and lateral basal segmental PA of the LLL

Anterior basal segmental PA of the RLL Lateral basal segmental PA of the RLL c

Posterior basal segmental PA of the lower lobes

Fig. 3.6 a The axial image shows the lateral location of the medial and lateral segmental pulmonary arteries of the middle lobe with respect to the corresponding bronchi. b Both the lower lobar pulmonary arteries and the apical segmental bronchi of both lower lobes are seen on this image. c The axial image at the level of the lower lobes shows the basal segmental pulmonary arteries running laterally relative to the corresponding bronchi, on both sides. LLL, Left lower lobe; RLL, Right lower lobe

Aorta and Supra-aortic Trunks

4

Amelia Sparano, Gennaro Barbato

L. Romano, M. Silva, S. Fulciniti, A. Pinto (eds.) MDCT Anatomy – Body © Springer-Verlag Italia 2011

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Anonymous trunk

Ascending aorta

Descending thoracic aorta

a

Pulmonary trunk Aortic root Left ventricle

b

Anonymous trunk Left subclavian artery

Aortic arch

c Fig. 4.1 a The thoracic aorta arises from the left cardiac ventricle through the semilunar valve, at the level of the lower border of the third left costal cartilage. b The ascending aorta passes upwards towards the right until it reaches the level of the lower border of the right second costal cartilage. From above downwards, it is related anteriorly with the right ventricle and posteriorly with the left atrium and right pulmonary artery. c The aortic arch describes a curve that is concave forwards; it passes behind to the left, remaining in front of the trachea on its left side. The supra-aortic trunks arise from the aortic arch

4 Aorta and Supra-aortic Trunks

Aorta

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Aortopulmonary window

a

Esophagus

Descending aorta

b

Liver dome Descending aorta

c

Fig. 4.2 a The aortic arch begins at the level of the second costal cartilage and runs behind the trachea until it reaches the fourth thoracic vertebra (TIV). b The descending thoracic aorta is continuous with the aortic arch. c It runs from the body of TIV to TXII, where it is continuous with the abdominal aorta. The descending aorta gives rise to visceral (bronchial, pericardial, esophageal, and mediastinal) and parietal (intercostal, subcostal, superior phrenic) branches

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Right common carotid Left common carotid

Anonymous trunk

a

Right common carotid

Left common carotid

b

Right external carotid Carotid bulb Right common carotid

c Fig. 4.3 a The supra-aortic trunks are the principal arteries supplying the head, neck, arms, and part of the thorax. The first branch arising from the right side of the aortic arch is the brachiocephalic (or anonymous) trunk; it ascends obliquely to the right and divides into the right subclavian and right common carotid arteries. b Both common carotid arteries arise from the superior thoracic outlet and run upwards through the neck. c At the level of the upper border of the thyroid cartilage, the common carotid artery divides into the internal and external carotid arteries. The bifurcation of the common carotid artery is somewhat dilated and is called the carotid bulb

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Right external carotid

Superior thyroid artery

a

Right internal carotid

b

Right vertebral artery

c Fig. 4.4 a The external carotid artery initially lies more medially and anteriorly to the internal carotid artery, then posteriorly and somewhat laterally, passing through the mastoid process and mandibular angle. b The vessel gives off multiple branches to both deep and superficial neck structures. The internal carotid is the principal artery supplying the brain; it enters the skull through the carotid foramen, at the apex of the os petrosum, and runs upwards into the cavernous sinus. c The vertebral arteries arise from the subclavian artery, on the left side, and the brachiocephalic trunk, on the right side. These arteries run upwards and back, laterally through the vertebral foramina, from C6 to C1, and then enter the skull through the occipital foramen. They finally join at the base of the skull to form the basilar artery

Bronchial Arteries and Vena Cava

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Giovanna Russo, Cesare Giglio

L. Romano, M. Silva, S. Fulciniti, A. Pinto (eds.) MDCT Anatomy – Body © Springer-Verlag Italia 2011

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Ascending aorta Right main pulmonary artery

Left upper pulmonary vein

Right bronchial artery Descending aorta

a

Aortic arch Superior vena cava Left bronchial artery

b

Aortic arch Left bronchial artery Pulmonary artery (common trunk)

Left atrium

Left main bronchus c

Fig. 5.1 a Axial maximum-intensity projection (MIP) image shows the right bronchial artery. The bronchial arteries provide nutritive elements to support airway structures through the vasa vasorum. b Axial MIP image shows the left bronchial artery originating from the descending aorta. c Sagittal MIP image shows the tortuous left bronchial artery. The bronchial arteries are located in the posterior mediastinum, below the aortic arch. Since their course is not parallel to the axial scan plane, they are not always easy recognized on axial images. Thus, MIP and sagittal multiplanar reconstruction (MPR) images are very important for their identification

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Right brachiocephalic vein

Left brachiocephalic vein

Right brachiocephalic artery

Left common carotid artery

Trachea

Left subclavian artery

a

Left brachiocephalic vein

Right brachiocephalic vein

Aortic arch

Esophagus

b

Superior vena cava

Aortic arch

Trachea

Esophagus

c Fig. 5.2 a Axial MIP image of the superior mediastinum at the level of a plane passing through the manubriosternal joint shows the anatomical relationships between systemic arterial and venous vascular structures. Brachiocephalic veins lie anteriorly with respect to the right brachiocephalic, left common carotid, and left subclavian arteries. The axial image also shows the origins of the right brachiocephalic artery, left common carotid artery, and left subclavian artery. b Axial MIP image shows the oblique course of the left brachiocephalic vein and the vertical course of the right brachiocephalic vein. c Axial image identifies the origin of the superior vena cava at the confluence of the brachiocephalic veins and aortic arch, which runs above the left main bronchus

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Ascending aorta

Superior vena cava Right upper lobe pulmonary artery

Left main pulmonary artery

Azygos vein Descending aorta a

Right brachiocephalic vein

Left brachiocephalic vein

Right brachiocephalic artery

Left common carotid artery

Superior vena cava

Right atrium b

Right brachiocephalic vein

Arch of the azygos vein

Superior vena cava Right upper pulmonary artery Right upper pulmonary vein

Right main pulmonary artery c

Fig. 5.3 a An axial plane below the aortic arch shows the azygos vein and superior vena cava running, respectively, behind and above the right main bronchus. b Coronal MIP image shows the anatomical relationships between the mediastinal vascular structures: the brachiocephalic veins are anteriorly located and anastomose to create the superior vena cava. The image also shows the aortic arch and the first two supra-aortic branches: the brachiocephalic and left common carotid arteries. c Sagittal MIP image shows the arch of the azygos vein, which runs above the right main bronchus to emerge at the superior vena cava. The image also shows the right pulmonary hilum and the anatomical relationships between vascular and bronchial structures

5 Bronchial Arteries and Vena Cava

Superior vena cava

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Ascending aorta

Arch of the azygos vein

Descending aorta

Esophagus

a

Arch of the azygos vein

Superior vena cava

Pulmonary artery

Inferior vena cava

Right atrium b

Descending aorta Intercostal veins Hemiazygos vein Azygos vein c Fig. 5.4 a Axial image at a scanning plane passing below the aortic arch shows the arch of the azygos vein, which runs above the right main bronchus to emerge at the superior vena cava. The image also shows the ascending and descending aorta. b Sagittal MIP image shows the course of the arch of the azygos vein and the entrance of the superior and inferior vena cava in the right atrium. The relationships between right pulmonary vascular-bronchial hilum structures are appreciated as well. c Coronal MIP image shows the anatomy of the systemic thoracic veins: the course of the azygos vein and the confluence of the hemiazygos vein, which is partially obscured by the descending aorta. Intercostal veins are also visible

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Right upper pulmonary vein

Left atrium Left upper pulmonary vein

Right interlobar pulmonary artery

Left interlobar pulmonary artery Azygos vein a

Right atrium Right upper pulmonary vein

Left atrium Left lower pulmonary vein

Right lower pulmonary vein

b

Left main pulmonary artery Right main pulmonary artery Right upper pulmonary vein

Left upper pulmonary vein

Left atrium

Left ventricle

c

Fig. 5.5 a Axial image at a plane passing below the carina shows the outlet of the upper pulmonary veins into the left atrium. Note the independent course of the pulmonary veins relative to the bronchial course, in contrast to the pulmonary arterial branches running in the posterolateral position with respect to the corresponding bronchi. b Axial MIP image shows the outlet of the two right pulmonary veins and the left lower pulmonary vein into the left atrium. c Coronal MIP image shows the anatomical relationships between the pulmonary arteries and veins: the main branches of the arteries run higher than the upper pulmonary veins

5 Bronchial Arteries and Vena Cava

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Left atrium Right lower pulmonary vein

Left lower pulmonary vein

Left lower segmental pulmonary artery a

Right interlobar pulmonary artery

Right interlobar pulmonary artery

Right lower pulmonary vein

Left upper pulmonary vein

Left atrium

b

Right main artery pulmonary

Left lower pulmonary vein

Left upper pulmonary vein

Right upper pulmonary vein

Left atrium

c

Fig. 5.6 a Axial MIP image shows the outlet of the pulmonary veins at the posterior wall of the left atrium, The lower pulmonary artery segmental branches have a dorsolateral course relative to the corresponding bronchi. b At the level of the tracheal carina, a coronal MIP image shows the vertical course of the right and left interlobar pulmonary arteries and the relatively horizontal course of the lower pulmonary vein. c Coronal MIP image shows the outlet of the upper pulmonary veins at the posterior wall of the left atrium

Pleura and Pericardium

6

Silvana Nicotra, Raffaella Marino

L. Romano, M. Silva, S. Fulciniti, A. Pinto (eds.) MDCT Anatomy – Body © Springer-Verlag Italia 2011

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Upper lobe Middle lobe

Upper section of the right major fissure

Upper section of the left major fissure Inferior lobe

Inferior lobe a

Middle region of the left major fissure

Right major fissure

b

Middle lobe

Lingula Inferior region of the left major fissure

Inferior region of the right major fissure

Inferior lobe

Inferior lobe c

Fig. 6.1 a Pleuras are serous membranes enveloping each lung and are composed of visceral and parietal layers. The space between the two pulmonary lobes, where the visceral pleural layer reflects, is called the “interlobar fissure”. On the right, the major fissure divides the middle and upper pulmonary lobes from the inferior lobe; on the left, it divides the upper lobe from the inferior lobe. In the upper region of the chest, the upper section of the major fissure has a curvilinear aspect with a frontal concavity. b The middle region of the fissure has a rectilinear course. c At the level of the lower region of the chest, the major fissure changes course, with the curvilinear aspect becoming a line with an anterior convexity. In the case of pulmonary lobe collapse, this aspect may change

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Minor fissure (curvilinear “ground glass” opacity)

a

Minor fissure (thin curvilinear opacity)

b

Minor fissure (avascular zone with triangular pattern)

c Fig. 6.2 a The minor fissure, on the right side of the chest, separates the upper lobe from the middle pulmonary lobe. It usually has a horizontal course, but in some cases the anterior region of the fissure tends to deviate downwards. When anatomically incomplete, there is direct communication between the upper and middle lobes. Sometimes, the minor fissure is found on the left, between the lingula and the remaining upper lobe. The minor fissure has different appearances on axial scanning of the chest. In some individuals, it shows a curvilinear “ground glass” opacity. b In others, the minor fissure appears as a thin curvilinear opacity or c as a relatively avascular zone, with a triangular pattern

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Upper lobe Upper lobe

Minor fissure Major fissure

Major fissure

Inferior lobe

a

Right upper lobe Upper secondary fissure Minor fissure Right major fissure Middle lobe

Right inferior lobe b

Left upper lobe Upper secondary fissure Left major fissure

Left inferior lobe c Fig. 6.3 a The major fissure has an oblique course downwards and forwards, starting behind the level of the fifth thoracic vertebra, towards the diaphragm. The minor fissure shows a lightly oblique course. b In the sagittal plane of the right lung, the minor fissure appears as a curvilinear opacity with a horizontal course, and the major fissure as a curvilinear opacity with an oblique course. In some individuals, a secondary fissure, the “upper secondary fissure”, is observed at the same level and behind the minor fissure. c In the sagittal plane of the left lung, the major fissure appears as a curvilinear opacity with an oblique course downwards and forwards. On the left side, an “upper secondary fissure” is seen

6 Pleura and Pericardium

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Pericardium

Mediastinal fat Epicardial fat

a

Mediastinal fat

Epicardial fat Right atrium

Pericardium Left atrium

b

Right ventricle

Mediastinal fat

Pericardium

Epicardial fat Left ventricle

c Fig. 6.4 a The pericardium is a serous sac containing the heart and initial sections of the great cardiac vessels. It is composed of an external layer, or “fibrous pericardium”, and an internal layer, or “serous pericardium”. The usual appearance of the pericardium is a thin, light linear structure, between the posterior epicardial fat (localized between the myocardium and the pericardium) and the anterior mediastinal fat (external to the pericardium). b Under normal conditions, the pericardium forms a thin linear structure, 2- to 4-mm thick. c In more caudal sections, a slight increase in pericardial thickness is observed

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Aortic arch

Superior aortic recess Anterior pericardial wall

a

Pericardium

b

Anterior pericardial wall

Posterior pericardial wall

c

Fig. 6.5 a The fibrous pericardium appears as a top-upwards cone surrounding the great vessels, which originate from the heart. The base of the cone lies on the phrenic center of the diaphragm. The pericardial cone is slightly flattened anteroposteriorly and has an anterior and a posterior surface. Anterior to the ascending aorta is the superior aortic recess of the pericardium. b In coronal sections, particularly if there is fluid in the pericardial sac, the cone shape of the pericardium is clearly evident as a thin linear opacity enveloping the heart and the origin of the great cardiac vessels. c The posterior surface of the pericardial sac is located in front of the descending thoracic aorta

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Ascending aorta

Superior aortic recess

Pulmonary artery trunk

Left pulmonary recess Pulmonary artery left branch a

Superior aortic recess Ascending aorta

Pulmonary artery trunk

Transverse sinus

Descending aorta b

Upper section of the superior aortic recess

Ascending aorta Pulmonary artery right branch

Left superior pulmonary vein

Oblique sinus

c Fig. 6.6 a This axial image shows the pericardial recesses among the great cardiac vessels, where the visceral layer folds directly into the parietal one. The superior aortic and left pulmonary recesses are extensions of the transverse sinus. The triangular anterior region of the superior aortic recess is localized between the ascending aorta and the pulmonary artery trunk. The left pulmonary recess is in front of the left branch of the pulmonary artery. b The transverse sinus, behind the ascending aorta, occupies the most anterior portion of the precarinal adipose tissue, running from right to left among the main pulmonary arteries. c The oblique sinus lies behind the left atrium, between the pulmonary veins. Pericardial recesses must be distinguished from lymph nodes, according to position, morphology, and densitometric characteristics

Mediastinal Compartments, Lymphatic System, and Esophagus

7

Natale Minervino, Francesco Varchetta, Mariano Scaglione

L. Romano, M. Silva, S. Fulciniti, A. Pinto (eds.) MDCT Anatomy – Body © Springer-Verlag Italia 2011

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Left carotid artery Anonymous artery

Left subclavian artery

Trachea Esophagus

a

Brachiocephalic vein trunk Sternum Left carotid artery Superior vena cava Left subclavian artery

Trachea

b

Thymus Anterior mediastinum

Superior vena cava Arch of the azygos vein

Aortic arch Trachea

c Fig. 7.1 a The anterior mediastinum extends from the thoracic inlet to an axial plane passing through the superior aspect of the aortic arch and corresponds to the retrosternal space. At this level, three major arterial vascular branches, the epiaortic vessels, arise from the aortic arch, left subclavian artery, left carotid artery, and anonymous artery. b Another anatomical landmark is the left brachiocephalic vein trunk, located in front of the epiaortic vessels. c The anterior mediastinal space, which consists of a variable quantity of fatty tissue containing the prevascular lymph node chain, is the site of the thymus, whose size varies with age. The gland is bordered inferiorly by the aortic arch

7 Mediastinal Compartments, Lymphatic System, and Esophagus

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Sternum Aortic arch Anterior mediastinum (retrosternal space)

a

Prevascular lymph nodes

Internal mammary artery

Anterior mediastinum (retrosternal space) Pulmonary artery

b

Mediastinal aditus

Brachiocephalic vein trunk

Prevascular lymph node Adipose tissue of the anterior mediastinum

Mediastinal pleura

Mediastinal pleura

c Fig. 7.2 a Multiplanar reconstruction (MPR) in the sagittal plane allows optimal visualization of the anterior mediastinal space in the cranio-caudal direction and corresponds to the space between the upper 2/3 of the sternum and root of the aortic arch. b Sagittal reconstruction allows longitudinal representation of the internal mammary artery and displays several prevascular lymph nodes immersed in the normal adipose tissue matrix of the anterior mediastinum. c MPR in the coronal plane allows visualization of the anterior mediastinal space, bounded laterally by mediastinal pleural layers

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Superior vena cava Aortic arch Lymph nodes of Barety’s space Esophagus Trachea a

Ascending aorta

Pulmonary artery

Right paratracheal lymph node

Descending aorta

Arch of the azygos vein Trachea b Right brachiocephalic arterial trunk

Lymph node of Barety’s space

Aortic arch

Superior vena cava Pulmonary artery Right pulmonary artery

c Fig. 7.3 a The middle mediastinum extends from the aortic arch to the heart and consists of numerous structures, recesses, and spaces. Barety’s space, or the right paratracheal space, is located below the superior vena cava and the trachea wall posteriorly; it is occupied by the right paratracheal lymph nodes, which form an important draining station for both lungs. b This space is bounded laterally by the azygos vein, an important vascular anatomical landmark. c Barety’s space has a parallelepiped shape and extends in a cranio-caudal direction. It develops along the right wall profile of the trachea, from a plane passing through the right subclavian artery up to a plane passing through the right pulmonary artery

7 Mediastinal Compartments, Lymphatic System, and Esophagus

Ascending aorta

49

Pulmonary artery trunk

Superior vena cava

Aortopulmonary window Descending aorta

a

Aortic arch Lymph node of the aortopulmonary window

Barety’s space

Pulmonary artery Carinal space

b

Barety’s space

Lymph nodes of Barety’s space

Aortopulmonary window

Communication between Barety’s space and the aortopulmonary window c

Fig. 7.4 a The aortopulmonary window is another important space in the middle mediastinum. This area, located between the concave bottom of the aortic arch and the upper convexity of the pulmonary trunk and left pulmonary artery on the left side, is larger than Barety’s space. b It is occupied by the left paratracheal lymph nodes and communicates freely with the carinal area below. c On a more anterior frontal scan plane, this MPR image shows the direct communication medially between the aortopulmonary window and Barety’s space

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Pericardium

Ascending aorta Right pulmonary artery

Precarinal space Carina Descending aorta

a

Lymph node

Carinal lymph node

Infracarinal space b

Barety’s space Aortopulmonary window Subcarinal space Subcarinal lymph node Esophagus c Fig. 7.5 a The carinal space also belongs anatomically to the middle mediastinum. It is bordered by the tracheal carina, the main bronchus above, and the left atrium below. Typically, on the axial plane, in a head-to-feet direction, the precarinal space, b infra-carinal space, and c subcarinal space are visible. At this level, there is direct communication with Barety’s space on the right and the aortopulmonary window on the left. In general, all mediastinal lymph nodes between 0.3 and 0.6 cm on the transverse plane are considered normal. Due to increased drainage in the territories of the lymph nodes of the tracheal bifurcation, lymph nodes are considered pathological only when larger than 11-12 mm

7 Mediastinal Compartments, Lymphatic System, and Esophagus

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Vertebra

Para-esophageal lymph node Azygos vein

Hemiazygos vein Left costovertebral joint

Right costovertebral joint a

Left atrium Esophagus Para-aortic lymph node

Descending aorta

Diaphragmatic pillar

Diaphragmatic pillar b

Esophagus

Para-esophageal lymph node Descending aorta

c

Fig. 7.6 a The posterior mediastinal space extends from the heart to the diaphragm and is bordered by the vertebral bodies and the costovertebral joint. It contains the descending aorta, esophagus, thoracic duct, the azygos and hemiazygos veins, and nervous and lymphatic structures. b This space consists of prevertebral soft tissue, which surrounds the descending aorta in the direction of the diaphragmatic pillars. c In this space, para-esophageal and para-aortic lymph nodes are visible

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Left atrium Adipose tissue of the posterior mediastinum

Esophagus

Diaphragm Stomach a

Esophagus Para-esophageal lymph node

Diaphragmatic crura

Adipose tissue of the posterior mediastinum

Diaphragmatic pillar

Descending aorta b

Esophagus

c

Fig. 7.7 a The posterior mediastinal space consists of adipose tissue, which surrounds the esophagus and the descending aorta. b This fatty envelope, which is very limited in the upper and middle mediastinum, is represented more precisely at this level, especially in the retrocrural space. c MPR sagittal view optimally depicts the intrathoracic esophagus

Heart and Coronary Arteries

8

Francesco Varchetta, Natale Minervino, Mariano Scaglione

L. Romano, M. Silva, S. Fulciniti, A. Pinto (eds.) MDCT Anatomy – Body © Springer-Verlag Italia 2011

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Right ventricle Interventricular septum

Right atrium

Left ventricle

Interatrial septum

Right atrium

a

Cardiac apex

Pericardium Aortic bulb

Pericardium Left coronary groove

Left atrium b

Left superior pulmonary vein

Right ventricle Left atrium Posterior coronary groove Cardiac apex c

Fig. 8.1 a The heart consists of four chambers: two atria and two ventricles. The atria are located posteriorly to the ventricles, one on the right and one on the left, and are separated by the interatrial septum. The conically shaped left and right ventricles are separated by the interventricular septum, analogous to the atria. b The left ventricle communicates with the left atrium posteriorly and with the aortic bulb medially. c The left ventricle forms the cardiac apex distally, while the rear edge of the ventricle is marked by the coronary grooves, which delimit it from the atria

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Ascending aorta Superior vena cava

Right atrium Right ventricle Inferior vena cava a

Pulmonary artery Outflow tract

Right ventricle

Left atrium

b

Left pulmonary artery Ascending aorta Left auricle

Right auricle

Right ventricle

c

Fig. 8.2 a The two main veins, the superior vena cava and inferior vena cava, flow into the right atrium, which communicates with the right ventricle inferiorly. b The pulmonary artery takes origin from the right ventricle, whose outflow tract is 3 cm in diameter. c The atria extend forwards to form two flattened offshoots, called auricles. The right auricle leans on the aorta while the left auricle partially covers the pulmonary artery

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Pericardium Tricuspid valve, inferior edge

Papillary muscle

Chordae tendineae

Tricuspid valve, septal edge

Mitral valve, posterior edge

a

Left atrium

Chordae tendineae

Mitral valve, anterior edge

Trabeculae carneae

Mitral valve, posterior edge

Papillary muscle b Left coronary sinus Right coronary sinus

Non-coronary sinus

Right cusp Anterior cusp

Left cusp c Fig. 8.3 a The atrioventricular valves are divided into the tricuspid valve on the right and the mitral valve on the left. They consist of fibrous flaps attached to the base of the ventricles and are held by tendinous cords related to the papillary muscles. b The papillary muscles adhere to the floor of the ventricles and are often joined by trabeculae carneae, belonging to the ventricle. c The arterial valves are called semilunar valves. The edges of the aortic semilunar valves form three sinuses, two of which are the origins of the coronary arteries. The cusps forming the pulmonary valve are located in front, on the right and on the left

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Right coronary artery (RCA)

Left circumflex artery (LCX) Left anterior descending artery (LAD)

RCA branch Right anterior descending artery (LAD)

LAD branch

a

Left main coronary artery

LCX

LAD

RCA

Conus artery

b

Conus artery Left posterolateral branch

RCA branch

Posterior descending artery (PDA)

RCA

c Fig. 8.4 a The coronary arteries are terminal arteries arising from the aorta and arranged on the surface of the heart. They are divided into the right coronary artery (RCA), left circumflex artery (LCX), and left anterior descending artery (LAD). b The left main coronary artery originates from the left aortic sinus and generates the LCX and LAD, while the RCA originates from the right aortic sinus. c The RCA runs laterally in the right coronary groove, generating secondary branches of the artery, such as the conus artery, until the posterior interventricular sulcus, where it forms the posterior descending artery (PDA) and left posterolateral branch

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Left main coronary artery Ascending aorta LCX Secondary branch of the LCX

LAD

a

LAD

LAD branch

LCX b

LAD

Left main coronary artery

LCX

RCA

Secondary branch of the LCX

Posterior branch of the LCX c

Fig. 8.5 a Two arteries originate from the common trunk of the left coronary artery (LCA) to supply the left ventricle: the LCX, which runs along the left coronary sinus and ends after the long axis of the left ventricle, and the LAD, which is obliquely directed towards the left ventricle and ends in the apical portion of the right ventricle, next to the cardiac apex. Secondary branches (diagonal vessels) originate from the LAD and run dorsally to the right ventricle. b The secondary branches of the LAD and LCX supply the superior-lateral portion of the left ventricle. c The secondary branches of the LCX are spread laterally and posteriorly relative to the left ventricle

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Great cardiac vein Posterior left ventricular vein

Left coronary sinus Vena cardiaca media

a

LAD

Middle cardiac vein

Posterior left ventricular vein

b

LAD Great cardiac vein

Left coronary sinus Posterior left ventricular vein c

Fig. 8.6 a The posterior vein of the left ventricle and the middle cardiac vein converge into the coronary sinus, which is a major collecting station and which runs transversely in the groove between the left coronary sinus and the right atrium. b The great cardiac vein runs next to the LAD dorsally along the left ventricle, passing through the coronary sinus to the left. c The great cardiac and posterior left ventricular veins converge into the coronary sinus

Chest Wall

9

Silvana Nicotra, Gennaro Barbato

L. Romano, M. Silva, S. Fulciniti, A. Pinto (eds.) MDCT Anatomy – Body © Springer-Verlag Italia 2011

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Pectoralis major muscle

Sternocleidomastoid muscle

Pectoralis minor muscle

Internal jugular vein

Trapezius muscle a

Pectoralis major muscle

Right clavicle

Pectoralis minor muscle

Right subclavian artery

1° left rib

Anterior serratus muscle

b

Pectoralis major muscle

Pectoralis minor muscle

Anterior serratus muscle

Intercostal muscles

c Fig. 9.1 a The sternocleidomastoid muscle is on the anterolateral side of the neck. It has two different origins, sternal and clavicular, which merge to form a single muscle trunk. Anteriorly, the muscle is connected with the cutaneous plane, and posteriorly with the internal jugular vein. The pectoralis major muscle anteriorly forms a large part of the chest wall and axillary cavity. Its superficial surface is connected with the mammary gland, while the deep surface covers the sternum, outer intercostal muscles, and pectoralis minor muscle. The trapezius extends in the nuchal region and along the posterior wall of the chest. b The pectoralis minor lies deeper than the pectoralis major. c The anterior serratus muscle covers the lateral wall of the chest

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Left subclavian artery

Right subclavian artery

Subscapularis muscle Anterior serratus muscle

Supraspinatus muscle a

Subscapularis muscle

Infraspinatus muscle

Supraspinatus muscle

Deltoid muscle

b

Subscapularis muscle

Infraspinatus muscle Supraspinatus muscle

Trapezius muscle c

Fig. 9.2 a The subscapularis muscle lies in the subscapular fossa. Its anterior surface is connected with the anterior serratus muscle and neurovascular axillary bundles. b The infraspinatus muscle lies in the infraspinatus fossa of the axilla. Its superficial aspect is connected with the trapezius and deltoid muscles and with the skin. The deep surface is connected with the capsule of the shoulder joint. c The supraspinatus muscle lies in the supraspinatus fossa of the scapula. Its superficial surface is connected with the trapezius and deltoid muscles. The deep surface lies in the scapular fossa and is connected with the shoulder joint capsule

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Subscapularis muscle Supraspinatus muscle

Infraspinatus muscle Trapezius muscle

Trapezius muscle a

Sternum

Right intercostal muscles

Rib Left intercostal muscles

Trapezius muscle b

Subscapularis muscle

Latissimus dorsi muscle

Infraspinatus muscle Right rhomboid muscle

Trapezius muscle c

Fig. 9.3 a The trapezius muscle is located in the posterior chest wall. Its superficial surface is directly covered by skin, while its deep surface is connected with supraspinatus muscle fascia. b The intercostal muscles occupy the intercostal spaces and are divided into outer, middle, and inner muscles. c The rhomboid muscle lies in the lower nuchal region and in the upper region of the back. It is covered by the trapezius muscle

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Pectoralis minor muscle Intercostal muscles

Latissimus dorsi muscle

Anterior serratus muscle Anterior serratus muscle

Rib

a Subscapularis muscle

Subscapularis muscle Latissimus dorsi muscle

Latissimus dorsi muscle

Anterior serratus muscle

b

Subscapularis muscle Latissimus dorsi muscle

Intercostal muscles

Anterior serratus muscle

Anterior serratus muscle

c

Fig. 9.4 a The anterior serratus muscle lies in the lateral wall of the chest. Its superficial surface is connected with the pectoralis minor, pectoralis major, and subscauplaris muscles. Its deep surface covers the ribs and the intercostal muscles. b The latissimus dorsi muscle covers the inferior and lateral parts of the back and the lateral wall of the chest. c In the anterolateral section of the chest, the latissimus dorsi muscle covers the anterior serratus muscle

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Subscapularis muscle Infraspinatus muscle Intercostal muscles Latissimus dorsi muscle

Latissimus dorsi muscle

a Supraspinatus muscle

Subscapularis muscle Infraspinatus muscle

Intercostal muscles Latissimus dorsi muscle

b

Erector muscles of the spine

Spinal vertebral processes

c

Fig. 9.5 a In the posterolateral part of the back, the deep surface of the latissimus dorsi muscle is connected with the intercostal muscles. b In the upper lateral part of the chest, the deep surface of the latissimus dorsi muscle is connected with the inferior part of the infraspinatus muscle. c The erector muscles of the spine form the deepest muscle layer of the back. They lie behind the spine, appearing as two fleshy masses in the costovertebral gutter beside the midline formed by the spinous processes

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Clavicle

Sternoclavicular joint

Manubrium of the sternum Body of the sternum Xiphoid process of the sternum

a

Posterior arch of the 6° rib

Anterior arch of the 3° rib

Body of the sternum

11° floating rib b

Scapula

Vertebral lamina

Transverse process

Spinous process c Fig. 9.6 a The sternum closes the ribcage anteriorly, exending downwards from the level of the third to the level of the ninth thoracic vertebra. It is composed of three sections: manubrium, body, and xiphoid process. b At the back, the ribs articulate with the dorsal vertebrae and limit most of the thoracic cavity. The ribs are mainly formed by a bony component (the proper rib), with a cartilaginous portion anteriorly. There are twelve pairs of ribs: the first seven are anteriorly joined to the sternum by their cartilaginous part. The eleventh and twelfth ribs are free and are called “floating ribs”. c Posteriorly, the ribcage is closed by the dorsal vertebrae. The vertebrae are divided into different segments: body, pedicle, lamina, transverse process, and spinous process

Part Abdomen

II

Diaphragm and Abdominal and Pelvic Walls

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Gianluca Ponticiello, Giuseppina Perrotta

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Right diaphragm: anterior part

Right hemidiaphragm: posterior part

a

Right diaphragm: costal part

Left diaphragm: costal part !

Right diaphragmatic crus

Left arcuate ligament b Anterior join of right and left hemidiaphragms: sternal part

Right arcuate ligament c Fig. 10.1 a The diaphragm consists of striated muscle and a central tendon. It contains several orifices, including one allowing passage of the inferior vena cava. The muscular component of the diaphragm is made up of sternal, costal, and lumbar portions, referring to the insertion site. The sagittal image clearly shows the anterior and posterior parts of the diaphragm. b The hemidiaphragms are inserted on the inner surface of the last six ribs. On the right, the presence of adipose tissue between the liver and the diaphragm clearly distinguishes these two anatomically contiguous structures. c The sternal, anterior portion of the diaphragm is inserted on the inner surface of the xiphoid process of the sternum. At this level, the two hemidiaphragms join to describe an arch that opens posteriorly

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a

Left hemidiaphragm

Right hemidiaphragm

b

Left diaphragm: anterior part Diaphragmatic discontinuity

c Fig. 10.2 a The medial diaphragmatic pillars (crura), which originate from the ventral surface of the second to fourth lumbar vertebrae, connect the aortic and esophageal orifices. The lumbar portion of the diaphragm (posterior part) is formed by the medial, intermediate, and lateral pillars. b The coronal view shows the continuity of the two hemidiaphragms, which laterally enclose the costodiaphragmatic recesses of the pleura. c This sagittal view shows an anatomical variant of the posterior portion of the left hemidiaphragm, in which a small discontinuity in the diaphragm’s profile is filled by adipose tissue

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Linea alba

Rectus abdominis muscle

a

Transverse abdominal muscle External oblique muscle

Internal oblique muscle

b

Spigelian fascia External oblique muscle

Rectus abdominis Internal oblique muscle

c Fig. 10.3 a The abdominal wall is composed of several structures: the skin, subcutaneous fat, muscles, extraperitoneal fat, and parietal peritoneum. The rectus abdominis muscles occupy the paramedian region of the anterior wall and extend from the xiphoid process of the sternum down to the pubis; they are separated centrally by the aponeurosis of the linea alba. b The presence of adipose tissue between layers of muscle fascia distinguishes the three muscles of the anterolateral abdominal wall: external oblique, internal oblique, and transversus abdominis. c The aponeurosis of the anterolateral abdominal muscles joins with the outer edge of the rectus abdominis muscle to form the spigelian fascia. A discontinuity in this fascia may be the site of a viscus herniation

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Subcutaneous fat

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Skin Anterolateral muscles

a

External oblique muscle Psoas muscle

Quadratus lumborum muscle Erector spinae muscle

b

Psoas muscle Quadratus lumborum muscle

Longissimus muscle

Multifidus muscle

c Fig. 10.4 a The external oblique muscle originates from the last eight ribs and inserts on the outer border of the iliac crest. The internal oblique muscle originates from the intermediate line of the iliac crest and from the thoracolumbar fascia, inserting on the last three ribs. The transversus abdominis muscle originates from the last six ribs, the thoracolumbar fascia, and the inner border of the iliac crest. It attaches on the rectus abdominis fascia. b The erector spinae muscles occupy the posterior abdominal wall, referred to as the paravertebral region. c The distal portion of the posterior abdominal wall is formed by the quadratus lumborum, longissimus, and multifidus muscles, which are the caudal continuation of the erector spinae muscle

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Pyramidal muscle Inguinal canal

Sartorius muscle

a

Internal oblique muscle

Rectus muscle Iliac muscle Psoas muscle

Gluteus maximus muscle

b

Pectineus muscle

Obturator externus muscle

Iliopsoas muscle

Obturator internus muscle Quadratus femoris muscle

c Fig. 10.5 a The pyramidal muscle directly continues the rectus abdominis muscle. It originates from the anterior surface of the pubis and inserts on the linea alba, cranially, at the pubic symphysis. The aponeurosis of the external oblique muscle and that of the transversus muscle (or transversalis fascia) are, respectively, the anterior and posterior walls of the inguinal canal and may be the sites of viscus herniation. b The psoas muscle has a vertical course and at the sacro-iliac synchondrosis joins with the iliac muscle. The latter is localized on the internal surface of the iliac ala and inserts on the femoral lesser trochanter. c The iliopsoas, pectineus, and obturator externus muscles form the anterolateral wall of the pelvis, crossing between the pubis and the posterior femoral surface

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Gluteus minimus muscle Gluteus medius muscle Piriformis muscle

Gluteus maximus muscle

a

Sartorius muscle

Rectus femoris muscle Quadratus femoris muscle Superior gemellus muscle

Inferior gemellus muscle

b

Obturator internus muscle

Obturator internus muscle Gluteus maximus muscle

c Fig. 10.6 a The group of superficial muscles of the posterior wall of the pelvis consists of the three gluteal muscles. The gluteus maximus muscle is located between the sacrum and the femur; the gluteus medius and gluteus minimus muscles lie between the iliac crest and femoral greater trochanter. b The deep muscles of the posterior wall of the pelvic bone are the piriformis, superior gemellus, inferior gemellus, and quadratus femoris muscles. They are directed horizontally, from the sciatic foramen to the greater femoral trochanter. c The obturator internus muscle originates from the anterolateral wall of the small pelvic cavity. It determines the limit of the obturator canal, passes through the small sciatic foramen, and inserts on the femoral greater trochanter

Peritoneal Cavity

11

Luigia Romano, Massimo Silva, Ciro Acampora

L. Romano, M. Silva, S. Fulciniti, A. Pinto (eds.) MDCT Anatomy – Body © Springer-Verlag Italia 2011

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Subdiaphragmatic peritoneum

Anterior parietal peritoneum

a

Posterior parietal peritoneum

b

Peritoneal fold

Peritoneal fold Peritoneal fold

c Fig. 11.1 a The peritoneum is a double-layered fold composed of a thin serous membrane called the mesothelium, which lines the abdominal cavity and covers its organs and viscera. It is divided into parietal and visceral layers and is limited by abdominal wall muscle, the diaphragm, and the pelvic brim. b The posterior folds and mesenteries separate between the peritoneal and retroperitoneal cavity. c The complex peritoneal architecture is due to the presence of many folds, ligaments, and mesenteries covering the gastrointestinal tract and other solid organs. All double layered folds of the peritoneum connect one viscus to another. The mesentery encloses the abdominal organs and connects them to the abdominal wall, while ligaments connect one viscus to another. The omentum is a multilayered fold extending between the viscera

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Superior mesocolic space

Superior mesocolic space Transverse mesocolon

Inferior mesocolic space

a

Falciform ligament

Left superior mesocolic space

b Falciform ligament

Right subphrenic space

c

Fig. 11.2 a A wide peritoneal fold covers the transverse mesocolon and divides the abdominal cavity into two parts, the superior and inferior mesocolic spaces. b The falciform ligament divides the superior mesocolic space into right and left spaces. It suspends the liver from the anterior abdominal wall and extends from the umbilicus up to the diaphragm, covering the liver dome. The falciform ligament is not visible, unless the peritoneal cavity is abnormally filled with air or fluid. c Ascites distends the peritoneal cavity, allowing visualization of the falciform ligament as a thin line separating the superior mesocolic space into right and left subphrenic spaces

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Superior left mesocolic space

Superior right mesocolic space

Stomach Right hepatic lobe Spleen

a

Duodenojejunal angle

b

Left colonic flexure

Extrahepatic biliary duct Descending duodenum c

Fig. 11.3 a The right superior mesocolic space is occupied by the liver, whereas the left contains the stomach and spleen (on the posterior side). b The left superior mesocolic space is occupied by the duodenojejunal angle (Trietz) and left colonic flexure. c The right superior mesocolic space contains the extrahepatic biliary duct, the duodenal bulb, and the descending duodenum

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Right subphrenic space

Phrenicocolic ligament Left colonic flexure

Anterior subhepatic space

a

Lesser omentum with gastric vessels Hepatic artery

Hepatoduodenal ligament

Portal vein

b

Extrahepatic biliary duct

Hepatic hilum

Portal vein

c Fig. 11.4 a The superior mesocolic space is divided into the anterior and posterior subphrenic spaces and the anterior and posterior subhepatic spaces (Morison’s pouch). The anterior and posterior right subhepatic spaces are anatomically continuous with the right subphrenic space. The reflection of the coronary ligament marks the site of non-peritonealized (bare) liver that continues with the retroperitoneal cavity. The right subphrenic space freely communicates with the inframesocolic compartment. The left subphrenic space is closed by the phrenicocolic ligament, which extends from the splenic flexure of the colon to the diaphragm, at the level of 11th rib. b The lesser omentum joins the lesser curve of the stomach and the proximal duodenum to the liver. It is continuous with the hepatoduodenal ligament. c The hepatoduodenal ligament extends from the hepatic hilum to the duodenum. It contains the common bile duct, hepatic and gastric vessels, and the portal vein

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Portal vein Lesser peritoneal sac Foramen of Winslow Vena cava

a

Stomach

Greater omentum

Small bowel loops

b

Greater omental fat

Greater omentum

Thin epiploic vessels

c Fig. 11.5 a The foramen of Winslow, located between the vena cava and the portal vein, represents the communication with the lesser peritoneal sac. The latter is bordered in front by the lateral hepatic lobe, the body of the stomach, and the greater omentum; in back by the pancreas, left adrenal gland, and kidney; and below by the transverse mesocolon. The lesser peritoneal sac is formed due to rotation of the stomach during fetal life, determining a peritoneal pouch separated from the rest of the peritoneal cavity. b The greater omentum is a wide square-shaped peritoneal fold attached to the greater gastric curve and extending down to fill the pelvic space (iliac fossa). It is located behind the anterior parietal peritoneum and protects the small and large intestinal bowel loops. c All peritoneal folds are composed of two thin layers of epithelium, whereas the greater omentum is made up of four layer containing large quantities of fat and thin epiploic vessels

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Inframesocolic space Duodenum Jejunal loops Ascending colon

Descending colon

Cecum Sigmoid colon a

Jejunal loops

Mesentery

Mesentery

Ileal loops Mesentery

b

Pancreas Superior mesenteric artery, branches

Superior mesenteric vein, branches

Mesenteric lymph nodes

c Fig. 11.6 a The inframesocolic space contains the small intestine and is bordered by the mesentery, cecum, ascending and descending colon, sigmoid colon, and mesosigmoid. The mesentery of the small bowel contains the peritoneal fold. Its root extends obliquely from the left border of the 2° lumbar vertebra (head of the pancreas) to the right sacro-iliac joint (right lower abdominal quadrant). The 15-cm-long root has a bare area that is in continuity with the retroperitoneal space. b The very long (8-9 m), ruffled peritoneal reflection of the mesentery encloses the jejunal and ileal loops, connecting them to the posterior abdominal wall. Jejunal mesenterial folds are shorter than ileal mesenterial reflections, such that the ileal loops able to move more freely than the jejunal loops. c The mesentery is formed on both sides by peritoneal epithelium containing loose connective and adipose tissue and enclosing lymph nodes, lymphatics, branches of the superior mesenteric artery and vein, as well as nerves passing to and from the viscera. The root of the mesentery crosses nearly horizontally in front of the pancreas, transverse mesocolon, duodenum, aorta, and inferior vena cava

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Ascending colon Descending colon Right paracolic gutter

Left paracolic gutter

Cecum

a

Cecum

Mesoappendix Appendix

b

Sigmoid mesocolon Pelvic space

c Fig. 11.7 a The right border of the fan-shaped mesentery completely envelops the cecum and anterior surface of the ascending colon, while the left border envelops the anterior surface of descending colon. The mesenterial reflections then continue on to cover the anterior abdominal wall on the right and left sides, determining the right and left paracolic gutters. b The peritoneum contains the cecum, at the level of the cecal-colonic junction, covers the appendix, and forms a reflection called the mesoappendix. A series of peritoneal recesses are formed extending obliquely along the left side of the ruffled mesentery of the small bowel, towards the right side of the mesentery, in the right lower abdominal quadrant. c The last peritoneal fold is the sigmoid mesocolon, which envelops loops of the sigmoid colon until the rectal-sigmoid junction. It divides the peritoneal pelvic space into two communicating compartments

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Anterior peritoneal reflection

Prevesical pouch

a Anterior abdominal wall, peritoneal fold Prevesical pouch Uterus Uterovesical pouch

Pouch of Douglas Rectum b

Rectovesical pouch Rectum c Fig. 11.8 a The peritoneal pelvic cavity is a direct continuation of the abdominal peritoneal cavity. Above the pubic joint, the parietal anterior peritoneal fold covers the genitourinary organs, closing below the peritoneal cavity while forming numerous peritoneal recesses. Inframesocolic compartments, including the paracolic gutters, preferentially reach the pelvic cavity. The sigmoid mesocolon gradually divides the pelvic peritoneal cavity into two compartments. b Between the anterior abdominal peritoneal reflection and dome of the bladder lies the prevesical pouch. Behind the bladder dome are peritoneal recesses that differ in females and males anatomically. In the female pelvis, the uterus divides the peritoneal rectovesical recess into the anterior uterovesical pouch, in front of the uterine fundus-body, and the pouch of Douglas, between the posterior surface of the uterus and anterior wall of the rectum. c In males, the anterior abdominal peritoneal reflection, after covering the dome of the bladder, continues to directly cover the anterior surface of the rectum with a single peritoneal pouch, the rectovesical pouch. Symmetric with the female pouch of Douglas and the male rectovesical pouch are lateral paravesical recesses that communicate directly with both paracolic gutters

Splanchnic Arteries

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Daniela Vecchione, Gennaro Barbato

L. Romano, M. Silva, S. Fulciniti, A. Pinto (eds.) MDCT Anatomy – Body © Springer-Verlag Italia 2011

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Splenic artery Common hepatic artery

Celiac trunk

a

Splenic artery Left gastric artery Common hepatic artery

b

Splenic artery

Common hepatic artery

Celiac trunk

c

Fig. 12.1 a The axial section shows the emergence of the celiac trunk, a large anterior branch of the abdominal aorta. It arises below the aortic hiatus of the diaphragm and the inferior phrenic arteries. b Volume rendering reconstruction shows the division of the celiac trunk into its three branches: hepatic artery, left gastric artery, and splenic artery. c The common hepatic artery runs horizontally to the right and forwards, passing in front of the right pillar of the diaphragm and through the upper margin of the pancreas

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Proper hepatic artery

Splenic artery Aorta

a Left hepatic artery

Common hepatic artery

Right hepatic artery

b Proper hepatic artery

Gastric artery

Common hepatic artery

c

Fig. 12.2 a At the the level of the duodenum, the common hepatic artery gives rise to the origin of its gastroduodenal branch and then penetrates the liver parenchyma as the proper hepatic artery. b The axial reconstruction, taken at the level of the hepatic hilum, shows the division of the proper hepatic artery into right and left branches, which are distributed within the corresponding liver lobes. c The proper hepatic artery gives rise to the right gastric artery as a collateral branch.This artery runs along the lesser gastric curvature to anastomose with the left gastric artery

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Left gastric artery Celiac trunk

a

Splenic artery

Aorta

b

Common hepatic artery

Splenic artery

c

Fig. 12.3 a The left gastric artery is the smallest branch of the celiac trunk. It provides branches for both surfaces of the stomach, as seen in this axial maximum-intensity projection (MIP) reconstruction. b The splenic artery is the largest branch of the celiac trunk. It runs horizontally and left towards the hilum of the spleen. It is located behind the stomach and the upper edge of the pancreas. c The splenic artery, in its final course, runs within the splenorenal ligament and divides into its terminal upper and lower branches before penetrating the splenic hilum (MIP axial reconstruction)

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Superior mesenteric artery

a

Inferior mesenteric artery

b

Splenic artery Hepatic artery Right renal artery

Superior mesenteric artery

c Fig. 12.4 a Axial image shows the origin of the superior mesenteric artery. This branch arises from the anterior surface of the abdominal aorta, just inferior to the origin of the celiac trunk. It travels in an anterior to inferior direction and ends in the right iliac fossa, where it anastomoses with its collateral branches (ileocolic artery). b Axial image shows the emergence of the inferior mesenteric artery from the aorta, 3-4 cm above the origin of the common iliac arteries. It travels downwards, in front of the aorta, and then along its left margin to end in the pelvis, where it becomes the superior rectal artery. c Volume rendering reconstruction shows the origins of the superior mesenteric artery, celiac trunk, and right renal artery

Iliac Arteries and Abdominal Aorta

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Stefania Daniele, Paolo Iovine

L. Romano, M. Silva, S. Fulciniti, A. Pinto (eds.) MDCT Anatomy – Body © Springer-Verlag Italia 2011

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Gastric fundus Inferior vena cava

Abdominal aorta

Liver

Spleen

a

Splenic artery

Celiac trunk Inferior vena cava

Splenic vein

b

Superior mesenteric artery Splenic artery

Right portal vein

Pancreas tail

c Fig. 13.1 a The suprarenal abdominal aorta is located between the diaphragm and the emergence of the celiac trunk. This aortic tract lies in front of the 12° thoracic vertebra and the 1° lumbar vertebra. Along the right side of the suprarenal abdominal aorta lie the inferior vena cava and left gastric fundus. b The celiac trunk is the first collateral branch arising from the anterior surface of the abdominal aorta, at the level of the 12° dorsal vertebra. It is divided into three main branches: hepatic artery, splenic artery, and left gastric artery. c The superior mesenteric artery is the second branch of the abdominal aorta. It originates approximately 2 cm below the celiac trunk and courses downwards along the posterior surface of the pancreas

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Right renal artery

Inferior vena cava

a

Left renal artery Right renal artery

Pancreas tail

Inferior vena cava Left renal hilum

b

Inferior mesenteric artery

c Fig. 13.2 a The infrarenal abdominal aorta is located between the origin of the two renal arteries. The right renal artery arises from the right anterolateral wall of the aorta, almost 1 cm below the superior mesenteric artery. The left renal vein passes in front of the aorta and superior mesenteric artery and then drains into the inferior vena cava. b The left renal artery arises from the lateral surface of the aorta to course behind the pancreas, where it reaches the left renal hilum. c The distal aortic tract is formed by the subrenal abdominal aorta, which is localized anterior to the 3° and 4° lumbar vertebrae. At this level, is the inferior mesenteric artery, the 5° abdominal aortic branch. It is localized 6 cm above the bifurcation of the iliac artery

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Inferior mesenteric artery 3° lumbar vertebra

a

Right lumbar artery

Left lumbar artery

Psoas muscle

Psoas muscle

b

Iliac bifurcation 4° lumbar vertebra

c

Fig. 13.3 a The inferior mesenteric artery descends diagonally downwards and to the left, giving rise to collateral branches. b The four lumbar arteries arise from the abdominal aorta. They surround the lumbar vertebral bodies and course behind the psoas muscle. c At the level of the 4° lumbar vertebra, the abdominal aorta divides into the two common iliac arteries

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Right common iliac artery

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Left common iliac artery 5° lumbar vertebra

a

Left external iliac artery

Right external iliac artery

b

Left external iliac artery

Right external iliac artery

Left internal iliac artery

Right internal iliac artery

Uterus

c

Fig. 13.4 a The common iliac arteries (right and left) are directed obliquely downwards and form an angle opening below, anterolateral to the body of the 5° lumbar vertebra. b The two common iliac arteries are directed towards the sacroiliac joints, with each artery dividing into external and internal iliac arteries. c The internal iliac artery originates at the level of the sacral promontory (sacrovertebral angle), courses downwards and posteriorly in the small pelvis, and divides into several muscular and visceral branches

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Inferior epigastric vessels

Inferior epigastric vessels

Left external iliac artery

Right external iliac artery

Uterus

a

Right external iliac artery

Left external iliac artery

Right external iliac vein

Left external iliac vein

b

Right common femoral artery

Left common femoral artery

Right common femoral vein

Left common femoral vein

c

Fig. 13.5 a The main branches of the external iliac artery are the inferior epigastric artery and the deep circumflex iliac artery. They supply the muscles of the lower anterior abdominal wall and anastomose with branches of the superior epigastric and phrenic arteries. b The external iliac artery is joined with the external iliac vein, which is located behind the artery. The two vessels lie along the internal border of the ileopsoas muscle. c Below the inguinal ligament, the external iliac artery continues as the femoral artery, which supplies branches to the lower limb, abdominal wall, and external genitalia. The femoral artery lies lateral to the femoral vein

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Left gastric artery Celiac trunk Splenic artery

Hepatic artery

a

Right renal artery Left renal artery Superior mesenteric artery

Inferior mesenteric artery

b

Left common iliac artery

Inferior mesenteric artery

Aortic bifurcation

Left internal iliac artery

Right external iliac artery

Left external iliac artery

c

Fig. 13.6 a Volume reconstructions of the abdominal aorta and its main branches shows the celiac trunk and its branches: hepatic artery, splenic artery, and left gastric artery; b the two renal arteries, which are directed laterally towards the corresponding renal hilum; the superior mesenteric artery, with its branches supplying the small intestine and right half of the colon; the inferior mesenteric artery, which originates just above the iliac bifurcation, supplying the left colon, the sigmoid colon, and rectum; and c the two common iliac arteries, which divide into the internal and external iliac arteries

Renal Arteries

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Daniela Vecchione, Paolo Iovine

L. Romano, M. Silva, S. Fulciniti, A. Pinto (eds.) MDCT Anatomy – Body © Springer-Verlag Italia 2011

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Right renal artery

Left renal artery

a

Right renal artery Aorta

b

Left renal artery Aorta

c

Fig. 141 a The axial image shows the origin of the renal arteries, which arise from the abdominal aorta at the bottom of the 1° lumbar vertebra. These arteries cross the medial pillar of the diaphragm and the psoas muscle to reach the renal hilum. b The right renal artery, longer then the left, travels behind the inferior vena cava, the head of the pancreas, and the descending portion of the duodenum. c The left renal artery is localized at a higher level than the right and travels behind the body of the pancreas and the splenic artery

Inferior Vena Caval System

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Inferior vena cava Confluence of the common iliac vein

a

Right common iliac artery

Left common iliac artery

Left common iliac vein

Right common iliac vein

b

Right common iliac vein

Left common iliac vein

c Fig. 15.1 a The inferior vena cava is the largest venous trunk of the abdominal cavity. It returns poorly oxygenated blood from the inferior limbs, pelvis, back, abdominal organs, and viscera to the right atrium. Blood from the gastrointestinal tract passes through the portal venous system before entering the inferior vena cava, through the liver parenchyma and suprahepatic veins. b The two common iliac veins join at the level of the 5° lumbar vertebra, forming an acute angle before draining into the inferior vena cava. At the same level, the common iliac arteries form a characteristic downwards-pointing Y shape and cross the confluence of the common iliac veins. c The common iliac veins are located near the corresponding arteries. They receive poorly oxygenated blood from the lower extremities, pelvic muscles, and pelvic urogenital organs

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Suprahepatic veins

Inferior vena cava

a

Right renal venous confluence

Superior mesenteric vein

b

Confluence of the inferior vena cava and right renal vein

c Fig. 15.2 a The inferior vena cava passes through the posterior abdominal compartment, in the extraperitoneal perivascular space, near the abdominal aorta and spinal column. After receiving blood from the three suprahepatic veins, it continues through the diaphragmatic hiatus, at the dorsal vertebral level. The branches of the inferior vena cava correspond to those of the abdominal aorta. b At the level of the 2° lumbar vertebra, the right renal vein drains directly into the inferior vena cava. The left renal vein is both larger and longer than the right. It crosses the abdominal aorta and then drains into the inferior vena cava. c The right renal vein has a very short course. The inferior and superior venae cavae are connected through the azygos lumbar veins

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Lumbar vein

a

Hepatic veins Portal vein (origin)

Inferior vena cava

b

Portal vein Hepatic hilum

Inferior vena cava

Splenic vein

c

Fig. 15.3 a The lumbar veins are paired tributaries of the inferior vena cava and parallel the corresponding arteries. They closely cross the lumbar spine. b The main suprahepatic trunks form in the liver parenchyma and carry hypo-oxygenated blood from the liver parenchyma (resulting from the portal and hepatic arterial supplies) directly into the inferior vena cava. The suprahepatic veins divide into three major trunks (left, right, and median) and several minor trunks. c At the hepatic hilum, the inferior vena cava is localized behind the portal vein

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Right suprahepatic vein

Left suprahepatic vein

Right portal vein

Right renal vein

a

Transdiaphragmatic vena caval tract Suprahepatic veins (major and minor trunks)

b

Median suprahepatic vein

Right suprahepatic vein

Left suprahepatic vein

c Fig. 15.4 a The three major suprahepatic trunks have short stems and drain directly into the anterior surface of the vena caval wall, at the level of the hepatic dome surface, immediately before the vena cava passes through the diaphragm and merges into the right atrium. b The minor suprahepatic veins are completely surrounded by liver parenchyma. They are longer, thinner, and more numerous (10-15) than the major veins. c The right suprahepatic trunk is obliquely oriented and collects blood from the right hepatic lobe. The left and median suprahepatic trunks collect blood from the lateral hepatic lobe and fourth hepatic segment, respectively. The caudate lobe has a proper venous system, with blood flowing directly into the lumen of the inferior vena cava

Venous Portal Circle

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Left portal branch Right portal branch Splenic vein Portal vein

Superior mesenteric vein a

Inferior mesenteric vein

Superior mesenteric vein

Colic vein

b

Suprahepatic veins Left portal branch Right portal branch Portal vein Superior mesenteric vein

c Fig. 16.1 a The portal vein is a large venous trunk that collects hypo-oxygenated blood from the subdiaphragmatic portion of the gastrointestinal tract, spleen, pancreas, and gallbladder. b At the level of the pancreatic head, the portal trunk is formed by the confluence of three major abdominal veins: superior mesenteric vein, inferior mesenteric vein, and splenic vein. c The superior mesenteric vein is the first branch of the portal confluence. It is localized in the mesenterial adipose tissue, which lies in the folds of the mesenterial fan, and crosses the horizontal portion of the duodenum, reaching the portal trunk directly. It receives blood from the intestinal mesenteric veins and the ileo-colic, middle colic, and pancreaticoduodenal veins

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Splenoportal venous axis Splenic vein

a

Pancreas

Inferior vena cava Abdominal aorta

Splenic vein

b

Left portal branch

Portal vein

Superior mesenteric vein Inferior mesenteric vein

c

Fig. 16.2 a The splenic vein is the third branch of the portal trunk and arises from the splenic hilum. b It horizontally passes through the supramesocolic abdominal space and is confined by the gastric body and pancreatic body and tail. c The inferior mesenteric vein is the second branch of the portal vein but in some individuals drains directly into the splenic vein. It is smaller than the superior mesenteric vein and passes parallel to the homonymous artery. The left colic vein, sigmoid veins, and superior hemorrhoidal veins drain into the inferior mesenteric vein

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Superior mesenteric vein Inferior vena cava

Abdominal aorta

a

Left colic vein

b

Gastric vein

Portal vein Splenic vein

c Fig. 16.3 a The superior mesenteric vein passes within the mesenterial fan, the large peritoneal reflection that suspends the loops of the small intestine, to collect blood from the intestinal veins. At the level of the mesenterial root, the superior mesenteric vein drains into the portal trunk, crossing the third portion of the duodenum and the uncinate process of the head of the pancreas. b Tributaries of the superior mesenteric vein are the intestinal-mesenteric, ileocolic, middle colic, and pancreaticoduodenal veins. c The portal trunk divides into its main branches at the liver hilum: the right branch (larger than the left branch) supplies the right hepatic and caudate lobes, while the left branch supplies the lateral hepatic lobe

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Left portal vein branch Main portal vein Right portal vein branch

a

Portal vein

Inferior vena cava

b

Portal vein Gastric vein Right segmentary intraepatic branch

Splenic vein

c Fig. 16.4 a At the level of the porta hepatis, the portal vein is enveloped by the hepatoduodenal ligament, a wide peritoneal fold covering hepatic hilar structures. This ligament also envelops the hepatic artery, main biliary duct, and lymph nodes. At the hepatic hilum, the portal trunk divides into right and left branches. b The left and right portal branches form the main portal intraparenchymal vessels of the liver. At all sizes and subdivisions, branches of the hepatic artery, portal vein, and bile ducts pass in close proximity to one another. Interlobular branches of the hepatic artery and portal vein form hepatic sinusoids, which collect into central veins and finally into the suprahepatic venous system. c Based on its arterial and portal vascular supply, the liver parenchyma is divided in eight segments, each drained by its own bile duct and hepatic vein branch

Abdominal Lymphatic System

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Inferior vena cava Aortic lymph nodes Aorta

a

Superior mesenteric artery

Mesenteric lymph nodes

b

Fig. 17.1 a The abdominal lymphatic channels and lymph nodes parallel the course of the major blood vessels and share their names: the aortic, celiac, and mesenteric lymph nodes. b Normal abdominal lymph nodes are usually < 1 cm in diameter. Nodal enlargement can result from inflammatory or neoplastic involvement. Increased adjacent fat tissue and vascular opacification facilitate the identification of lymph nodes on MDCT images

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Retrocrural nodes

Aorta

Diaphragm

a

Gastric lymph nodes

Stomach Left gastric artery

b

Hepatic artery

Portal vein

Hepatic lymph nodes

c

Fig. 17.2 a The retrocrural nodes are located along the aorta, at the level of the diaphragmatic hiatus. They connect the nodal groups of the posterior mediastinum with the para-aortocaval lymph nodes. b The gastric nodes are located along the lesser curvature, near the gastric artery. c The hepatic nodes are located close to the hepatic artery and along the hepatoduodenal ligament

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Portal vein

Portacaval nodes Pancreas

Inferior vena cava

a

Splenic artery

Splenopancreatic nodes

Inferior vena cava

Splenic vein

b

Celiac lymph nodes

Celiac trunk

Splenic vein

c

Fig. 17.3 a The portacaval nodes are easily seen on CT, directly posterior to the portal vein, along the hepatoduodenal ligament. They are also referred to as the “nodes of the foramen of Winslow” and form a pathway between the nodes of the stomach and nodes that drain the liver and bile ducts. b Splenopancreatic nodes are located along the splenic artery, posterosuperior to the pancreas and near the splenic hilum. c Celiac lymph nodes are located along the celiac trunk, in the retroperitoneum. They drain lymph from the upper abdominal organs, stomach, and intestine through a major lymphatic collector system, the intestinal trunk

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Superior mesenteric vein

Superior mesenteric nodes

Superior mesenteric artery

a

Aorta

Aortic nodes

Inferior vena cava

b

Aorta

Aortic nodes

Inferior vena cava

c Fig. 17.4 a The mesenteric lymph nodes are distributed in the mesenteric root, along the superior and inferior mesenteric arteries. They are the terminal station for lymphatic drainage from the large and small bowel. b Aortic or para-aortic nodes are located in the retropertioneum, along the aorta and inferior vena cava. c The para-aortic nodes drain much of the lymph from the lower extremities and abdominal wall. They serve as the primary nodal station for urinary and genital organs. The major para-aortic channels join with the intestinal trunk, at the level of L1, to form the thoracic duct, which passes through the aortic hiatus to enter the mediastinum and empty into the left subclavian or innominate vein

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Internal iliac artery

Internal iliac lymph nodes

a

External iliac artery External iliac nodes

External iliac vein

b Pubic bone

Inguinal nodes

c

Fig. 17.5 a The internal iliac or obturator nodes surround the internal iliac artery and can be visualized in the posterior pelvis. b The external iliac nodes are located along the external iliac artery, in the anterior pelvis. c The inguinal nodes are superficial, located anterolateral to the pubic bone. They often display central low-density or fatty degeneration

Gastroduodenal Tract

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Liver Stomach

Cardias

Aorta Spleen a

Diaphragm Liver Gastric fundus

Colon

b

Phrenic center

Inferior vena cava Cardias Liver

Aorta

c

Fig. 18.1 a The gastroduodenal tract extends from the cardia, which is the esophageal orifice into the stomach, to the duodenojejunal angle, which marks the beginning of the small intestine. The cardia is localized below the phrenic center, at the level of the 11° dorsal vertebra. The aorta is located behind the cardia, and the stomach is localized in the left subphrenic space, between the left hepatic lobe and spleen. b The fundus is the most cephalic part of the stomach, located close to the left hemidiaphragm and higher than the cardia. c The coronal view shows the location of the cardia, under the phrenic center, beside the inferior vena cava and abdominal aorta, and behind the left hepatic lobe

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Gastric body

Gastric antrum

Pancreas Jejunal loops

Liver

Spleen Right kidney a

Gastric folds (rugae)

Gastric antrum

Pylorus Colon Lesser gastric curvature

b

Bulb

Gallbladder Greater gastric curvature

Descending duodenum c

Fig. 18.2 a The gastric body is the main portion of the stomach. It is located on the left side of the lateral hepatic lobe, above the jejunal loops, transverse colon, pancreatic body and tail, and beside the spleen. b The gastric antrum is the vestibule of the stomach and is localized above the head of the pancreas and the transverse colon. The gastric rugae are redundant mucosal folds that are more evident when the stomach is empty, especially along the greater curvature. The gastric antrum is formed by thickened smooth muscle and is continuous with the pylorus, the sphincter opening into the duodenum. c Coronal view shows the borders of the stomach: the greater curvature forms the external margin, and the lesser curvature the internal margin. Both meet at the cardia and pylorus. The latter is continuous with the duodenal bulb

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Gastric antrum

Gallbladder

Pylorum Pancreas

Duodenal bulb

a

Gallbladder Jejunal loops Descending duodenum Pancreas head

Superior mesenteric artery

Right kidney b

Spleen Portal vein

Treitz angle

3rd duodenal portion

Celiac trunk and upper mesenteric vessels

Inferior vena cava c

Jejunal loops

Fig. 18.3 a The pylorus is the sphincter connecting the stomach and the duodenal bulb. It is located behind the gallbladder. The duodenal bulb is directly to the right of the abdomen, below the inferior border of the right hepatic lobe. The duodenum is the fixed portion of the small intestine and is retroperitoneal, except for the bulb. It has a concave shape and surrounds the head of the pancreas. b The descending duodenum courses parallel to the head of the pancreas, along the right side of the 2° to 4° lumbar vertebrae. The major pancreaticoduodenal papilla is located within this duodenal tract. c The third portion of the duodenum crosses the aorta and inferior vena cava, behind the celiac trunk and superior mesenteric vessels. The duodenojejunal junction is attached to Treitz’s ligament, forming the Treitz angle, at the left side of the superior mesenteric vessels and continuous with the jejunal loops

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127 Gastric fundus

Lateral hepatic lobe

Gastric body

Transverse colon Small intestine

a

Gastric body Pylorus Descending duodenum

Small intestine

Pancreas head

b Right colonic flexure Pylorus Stomach Transverse colon

Gallbladder

Right colonic flexure

Small intestine

c

Fig. 18.4 a Coronal view shows the relationships of the upper gastrointestinal tract. The stomach lies at the left side of the lateral hepatic lobe, on the surface of the transverse colon and above the loops of the small intestine. b After administration of oral contrast medium, it is possible to visualize the lumen of the stomach, with the pyloric valve, and the descending duodenum, around the head of the pancreas and proximal jejunal loops. c Coronal panoramic view after administration of oral contrast medium shows the stomach, between the inferior left hepatic border and right colonic flexure. The gallbladder is located along the left side of the pylorus, above the right colonic flexure. The greater gastric curvature is attached to the transverse colon by the gastrocolic ligament, which consists of a wide peritoneal fold

Small Intestine

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Luigia Romano, Ciro Petrella, Maria Giuseppina Scuderi

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Transverse colon Small intestine Ascending colon

a

Upper mesenteric vein

Duodenojejunal angle

Upper mesenteric artery

Mesentery

Terminal ileal loop b

Mesenteric vessels

Wall of the small intestine Ileocecal valve

Mesenteric folds

c Fig. 19.1 a The mesenteric small intestine is the most mobile and longest (8–9 m) segment of the gastrointestinal tract. It is surrounded by the colon and enveloped by a fan-shaped mesentery that suspends it from the posterior abdominal wall. b The mesentery contains arterial, venous, and lymphatic vessels. Of these, the superior mesenteric artery supplies the entire small intestine. The small intestine begins at the duodenojejunal angle and ends at the ileocecal valve. The jejunum represents the proximal 40% of the small intestine and is 2-3 m in length. It begins after the fourth portion and suspensory ligament of the duodenum and lies in the left upper abdominal quadrant. It is less mobile than the ileal tract due to its shorter mesentery. c Wall thickness varies according to the degree of lumen distention. The small intestine is characterized by mucosal and circular folds, the valvulae conniventes and plicae circulares, respectively

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Mesenteric vasa recta

Jejunal loops Mesenteric arterial branches

Ileal loops Ileal loops a

Ileal loops Descending colon

Ascending colon

Right ureter

Left ureter

Pelvic bone b

Lumbar spine

Abdominal wall

Sigmoidal loops

Ileal loops

Urinary bladder

c

Fig. 19.2 a Ileal loops follow the jejunal loops, with no clear anatomical point of distinction between these two intestinal tracts. The ileal loops represent 60% (4 m) of the small intestine by length. They are more mobile than the jejunal loops because of their longer mesentery. The ileal wall is thinner than the jejunal wall, with a less prominent pattern of folds and wider valvulae conniventes. The superior mesenteric artery sends 15-18 branches to the small intestine. These form arterial arcades and the vasa recta, which penetrate the intestinal wall. b The ileal intestine lies in the lower abdominal quadrants and pelvic space, where it is surrounded by the ascending and descending colon. Both ureters lie behind the ileal loops. c In the pelvic space, the ileal loops are surrounded by sigmoid intestine, urinary bladder, and, in females, the uterus and ovaries

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Stomach

Colon

Small intestine

Cecum Bladder a

Ileal loops

Pelvic bone Sacrum b

Left ovary

Right ovary

Uterus

Ileal loops Rectum

c Fig. 19.3 a The abdominal coronal view shows the entire small and large intestines. The colon surrounds the small bowel loops, like a picture frame. In this view, all of the gastrointestinal segments can be identified: the stomach and jejunal loops, in the left upper abdominal quadrant; the ileal loops, in the lower abdominal quadrants; and the large intestine, surrounding the small intestine. Small bowel loops are movable and have a characteristic undulating aspect. Symmetric, multiple, adjacent mesenteric recesses result in discrete separation of the ileal loops in the right lower quadrant. b In the pelvic spaces, the ileal loops occupy all of the peritoneal pouches. c Axial view of the female pelvis demonstrates the relationships of the ileal loops, ovaries, and uterus

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Transverse colon Jejunal loops Cecum Ileal loops with conniventes valvulae and circulares plicae

Terminal ileal loop

Sigmoid colon a

Left colonic flexure

Right colonic flexure

Small intestine

b Left diaphragm Stomach Transverse colon Left colonic flexure Small intestine Descending colon

c

Sigmoid colon

Fig. 19.4 a Oral contrast material (barium) reveals the relationship between the large and small intestine. The transverse colon forms a roof over the jejunal and ileal loops. The terminal ileal loop rises up to the cecum. b The transverse colon, with its left and right flexures, lies over the small bowel loops. The lumen is distended by transparent contrast medium. c Sagittal view after administration of oral contrast material (barium) shows the left side of the entire gastrointestinal tract, from stomach to sigmoid colon. Small bowel loops are seen in front of the descending colon. A series of peritoneal recesses is formed, extending along the ruffled mesentery of the small bowel, from the upper to the lower abdominal quadrant

Colon

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Luigia Romano, Ciro Petrella, Loredana Di Nuzzo

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Transverse colon

Left colonic flexure

Right colonic flexure Descending colon Ascending colon

Sigmoid colon

Cecum a

Large intestine

Rectum

Small intestine

b

Enhanced thin wall of the colon Collapsed descending colon

Pericolic fat

c

Fig. 20.1 a Optimal evaluation of the lumen of the large intestine requires thorough colonic cleansing followed by the introduction of negative contrast medium (air). The large intestine is 1.5-2 m in length, with the normal wall measuring ≤ 3 mm in thickness. The luminal margin is usually smooth, well outlined by air contrast on the mucosal side. The outer colonic margin is sharply demarcated by the surrounding pericolic fat. Loops of large intestine are distinguished by their larger caliber and the presence of haustral markings and gas within the lumen. b The large intestine consists of the cecum, ascending colon, transverse colon, descending colon, sigmoid colon, and rectum. The right colonic flexure is positioned between the ascending and transverse colon, and the left colonic flexure between the transverse and descending colon. The colon forms an anatomical frame around the small intestine. c CT scan after intravenous contrast material injection displays the colonic mucosa as a thin line of moderately high attenuation

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Intraperitoneal transverse colon

Retroperitoneal ascending colon

Retroperitoneal descending colon

Right kidney

Left kidney

a

Mesenteric fan Ileocecal valve Terminal ileum Cecum

b

Ascending colon

Appendix

Cecum

Pelvic bone

Bladder

c

Fig. 20.2 a The cecum, transverse colon, and sigmoid colon are intraperitoneal viscera whereas the ascending colon, descending colon, and rectum are retroperitoneal viscera. b The cecum is located laterally, in the right lower abdominal quadrant, and receives late ileal loops along the internal border, where the ileocecal valve is located. The maximum diameter of the cecum is 6-7 cm. This peritoneal viscus is attached to the posterior and lateral abdominal walls by peritoneal folds. The cecum is joined to terminal ileal loops through the ileocecal valve, which prevents the reflux of colonic contents into the lumen of the small intestine. The margins of the valve have a variable amount of submucosal fat, usually evident on CT. c Attached to the medial border of the cecum is the appendix, which is a blind, long diverticulum (length 6-12 cm) with a wide mesenterial fold (mesoappendix)

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Splenic colonic flexure

Liver

Stomach Hepatic colonic flexure

Transverse colon

Small bowel loops

a

Sigmoid colon

Small bowel loops Descending colon Ascending colon Left kidney Descending duodenum

Perirenal space

b

Perirectal space Sigmoid colon

Elevator ani muscle Ischiorectal space

Rectum c

Fig. 20.3 a The ascending colon extends from the cecum (and further, from the ileocecal valve) to the right colonic flexure. The transverse colon is suspended by a large peritoneal fold, the transverse mesocolon, and extends from the right (hepatic) to the left (splenic) colonic flexure. The descending colon begins at the left colonic flexure and ends at the sigmoid colon. b When not distended by air or contrast material, the descending colon is a collapsed viscus. It can be distinguished from small bowel loops by its posterior position, near the left kidney. c The sigmoid colon appears as a curved loop that passes posteriorly to the midline to become the rectum, in the extraperitoneal space. Multiple small bowel loops are located above the sigmoid colon. The rectal ampulla is a round air-filled viscus with a diameter of 2.5-3 cm. It is approximately 12 cm long, occupies a presacral extraperitoneal position, and is surrounded by perirectal adipose tissue. It ends in the anal canal. The ischiorectal fossa is the largest of the anorectal spaces and is bounded medially by the elevator ani and external sphincter muscles. The latter separates the ischiorectal space from the extraperitoneal pelvic space

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139 Diaphragm

Diaphragm

Stomach Liver Spleen Inferior hepatic border Hepatic colonic flexure

Descending colon

Sigmoid colon Cecum a

Aorta Superior mesenteric artery

Portal trunk

Ileocolic branch Ileocolic vein

b

Inferior mesenteric vein

Inferior mesenteric artery

c

Fig. 20.4 a The cecum, appendix, and transverse colon are mobile viscera enveloped by peritoneum. By contrast, only the anterior and lateral surfaces of the ascending and descending colon are surrounded by peritoneum, and they are fixed segments. The right colonic flexure is located below the inferior border of the liver, the transverse colon below the gastric antrum, and the left colonic flexure in front of the spleen and lateral to the stomach. Both colonic flexures are below the diaphragm. b The large intestine is supplied by the superior and inferior mesenteric arteries, while the cecum and appendix are supplied by the ileocolic branch of the superior mesenteric artery, the ascending colon by the artery’s right colic branch, and the transverse colon by its middle colic branch. Venous drainage of these segments is through the superior mesenteric vein. c The descending colon and sigmoid colon are supplied by the inferior mesenteric artery, with venous drainage of these segments by the inferior mesenteric vein. The rectum is supplied by branches of the superior and the inferior mesenteric arteries and by systemic branches (internal iliac arteries). Its venous drainage is through the corresponding veins

Liver

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Nicola Gagliardi, Sonia Fulciniti, Giuseppe Ruggiero

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Middle hepatic vein

Left hepatic vein Inferior vena cava

Right hepatic vein

a

Middle hepatic vein

Portal vein (left branch)

Portal vein (right branch)

Inferior vena cava Right hepatic vein

b

Portal vein (right branch)

Portal vein (left branch)

Right hepatic vein Portal vein (right branch)

Portal vein (right branch) c

Fig. 21.1 a The liver is located in the upper right quadrant of the abdominal cavity. Traditional gross anatomy divides the liver into four lobes: the right lobe, to the right of the falciform ligament; the left lobe, to its left, and the quadrate and caudate lobes, on the visceral surface. The vascular system comprises arterial, venous, and portal systems. The hepatic artery, hepatic vein, and portal vein are contained within the hepatoduodenal ligament. Axial section of the upper liver shows the confluence between the hepatic veins and inferior vena cava, before the latter flows into the right atrium. b In this section, the portal branches have a vertical course, bisecting the angle of the hepatic veins. The portal branches define the liver’s segmental anatomy. c The horizontal tract of the left branch of the portal vein divides the left lobe into two segments. Segment II is on the upper side, and segment III on the lower side

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Falciform ligament Portal vein (left branch) Stomach

Portal vein (right branch) Portal vein (right branch)

a

Common hepatic artery

Stomach Celiac artery

Portal vein (right branch)

b

Common hepatic artery

Celiac artery

Portal vein

c

Fig. 21.2 a The horizontal tract of the right portal vein separates the upper segments of the right lobe (VII and VIII) from its lower segments (V and VI). The falciform ligament separates segment IV, of the right lobe, from the left lobe. b The common hepatic artery has a horizontal course, on the same plane as the celiac artery. c The horizontal course of the portal vein is towards the confluence of the splenic vein

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Stomach Gallbladder Celiac artery Portal vein Splenic vein

a

Gallbladder Splenic vein

Duodenum

Superior mesenteric artery

Portal vein

b

Portal vein: segment VIII

Portal vein: segment VII

Portal vein: segment V

Splenic vein

Portal vein: segment VI

c

Fig. 21.3 a The right and left lobes are separated by the gallbladder. The portal vein is in front of the inferior vena cava. Often, the splenic vein is prominently seen. b The image shows the long axis of the gallbladder, with the cystic duct behind it. The superior mesenteric artery is seen in the center. c Coronal reformatted image shows the parenchymal distribution of the portal branches and hepatic segments

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Hepatic artery Splenic artery

a

Left gastric artery Hepatic artery (right branch)

Splenic artery

Hepatic artery

b

Fig. 21.4 a Maximum-intensity projection (MIP) reformatted image magnifies the arteries and shows the entire course of the hepatic and splenic arteries. In the middle of their origin, a fine arterial branch, the left gastric artery, is seen moving forwards, above the pancreas. b Coronal MIP reformatted image shows the common hepatic artery and its main right branches, the left gastric artery, and the splenic artery

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Right hepatic vein Left hepatic vein

Portal vein

Inferior vena cava Aorta a

Right hepatic vein Left hepatic vein

Aorta Inferior vena cava

b

Fig. 21.5 a Coronal maximum-intensity projection (MIP) reformatted image shows the right and left hepatic veins, which conduct blood flow to the inferior vena cava. The portal vein, lower portion of the inferior vena cava, and the aorta, with the splenic vein on the left, are also present. b Volume-rendering color-coded reformatted image magnifies the hepatic venous system. The inferior vena cava is seen to the right of the aorta and in the hepatic tract

Biliary System

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Francesco Di Pietto, Rosaria De Ritis, Anna Elia

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Biliary confluence Right hepatic duct

Left hepatic duct

Common hepatic duct

a

Pancreatic duct (of Wirsung)

Choledochus (common bile duct)

b

Portal vein Gallbladder (body)

Choledochus (common bile duct)

Gallbladder (fundus)

Duodenal papilla

Gallbladder (infundibulum) c Fig. 22.1 a The image shows moderate dilation of the intra- and extrahepatic biliary ducts, with the right and left hepatic duct merging to yield the biliary confluence. b The middle and distal portions of the choledochus (common bile duct) are located behind the head of the pancreas. Within the pancreatic gland, the moderately dilated pancreatic duct (of Wirsung) merges with the duodenum together with the choledochus. c The latter runs along the portal vein and drains into the duodenal papilla (ampulla of Vater). The gallbladder, located at the anterior-inferior edge of the liver, is divided into three parts: fundus, body, and infundibulum

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Biliary duct: segment II

Right hepatic duct Biliary duct: segment VII

a

Biliary duct: segment III

b

Biliary duct: segment VIII Choledochus (common bile duct) Biliary duct: segment VI

c

Fig. 22.2 a Segment VII of the biliary duct originates from the right hepatic duct, while segment II of is located in the left hepatic lobe. b Segment III of the biliary duct is located within the left hepatic lobe. c The right hepatic duct is the origin of segment VIII, which runs upwards, and segment VI, which runs downwards

Spleen

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Gianluca Ponticiello, Giuseppina Perrotta

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Spleen Splenic hilum Pancreatic tail

a

Stomach Spleen Left kidney

b

Splenic lobulation

c Fig. 23.1 a The spleen is located subdiaphragmatically, in the left hypochondriac region. It is an intraperitoneal organ, except for the hilar region, which gives rise to two peritoneal folds: posteriorly, the splenorenal ligament, containing the splenic vessels and pancreatic tail; and anteriorly, the gastrolienal ligament, which extends to the greater curvature of the stomach. b Relationships between the spleen and posterior wall of the stomach, retroperitoneal fat (containing the adrenal gland), left kidney, splenic flexure of the colon, and pancreatic tail can be appreciated. c Splenic loulation is a frequent anatomical variant

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Accessory spleen

a

Splenic artery

b

Splenic vein

c

Fig. 23.2 a The coronal view shows a small nucleus of accessory spleen, with densitometric characteristics comparable to those of the spleen. b The angiographic-like image highlights the splenic artery, from its origin at the celiac trunk to its terminus at the splenic hilum. Along its course, the artery gives off collateral branches, including pancreatic arteries and the posterior gastric artery. c The splenic vein drains blood from the spleen. It joins with the superior mesenteric vein to form the hepatic portal vein and follows a course superior to the pancreas, alongside the splenic artery

Extraperitoneal Spaces

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Posterior parietal peritoneum Transversalis fascia

a

Diaphragm

Extraperitoneal pelvic space Iliac vessels b

Anterior pararenal space

Perivascular space

Perirenal space

Posterior pararenal space

c Fig. 24.1 a The extraperitoneal space occupies the posterior half of the abdomen. It is closed anteriorly by the posterior parietal peritoneum and posteriorly by the fascia transversalis, which covers the dorsolumbar muscles and vertebral column. This space contains abundant fat tissue surrounding the pancreas, kidneys, adrenal glands lymph nodes, urinary collecting system, blood vessels, and nerves. b The extraperitoneal space extends from the diaphragm superiorly to the pelvic brim inferiorly, where the iliac vessels virtually separate the extraperitoneal abdominal space from the pelvic extraperitoneal space. c The extraperitoneal region is distinctly divided into five spaces by the presence of fascial planes. These dense elastic connective tissue sheaths envelop the kidneys, adrenal glands, and fat tissue. The five spaces are the perirenal space, anterior pararenal space, posterior pararenal space, perivascular space, and iliac space

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Descending colon Anterior pararenal space

Lateroconal fascia

Perirenal space

Psoas muscle

Posterior pararenal space

Quadratus lumborum muscle a

Pancreas head Inter-renal fascia

Perivascular space

b

Inter-renal septa

Inter-renal septa

c

Fig. 24.2 a The perirenal space is a paired compartment located between the anterior and posterior pararenal spaces. Medially, it is closed by the fasciae of the psoas and quadratus lumborum muscles. It surrounds the kidney, with its abundant perirenal fat. The perirenal fascia is divided into the anterior and posterior fascia and laterally continues along the abdominal wall, fusing with the lateroconal fascia, which covers the descending and ascending colon. b The perirenal fascia passes behind the body of the pancreas beyond the midline, where it constitutes the inter-renal fascia. The latter closes the perivascular space anteriorly. c Inter-renal septa pass through the perirenal space, connecting the kidney and extraperitoneal spaces

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Right adrenal gland Left perirenal space

Right kidney

a

Left renal pelvis Right ureteric junction

b

Left renal vein

Right renal artery

c Fig. 24.3 a On coronal CT, the perirenal space is well evidenced due to its abundant fat tissue, which surrounds the organs and other anatomical structures located within this diamond-shaped compartment. The major axis of the perirenal spaces is in the longitudinal direction, with two distinct symmetrical spaces localized beside the vertebral column. Each space contains a kidney and an adrenal gland. b Perirenal fat also envelops the renal pelvis and ureteric junction. c The renal artery and vein originate in the vascular extraperitoneal space and pass through the perirenal space, reaching the renal hilum. At the latter, the anterior and posterior ipsilateral perirenal fasciae fuse and blend with the hilar vessels, preventing communication between the two perirenal spaces across the midline

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Transverse mesocolon Lesser sac

Anterior pararenal space

a

Left paracolic gutter Right paracolic gutter

Left lateroconal fascia

Right lateroconal fascia

Perivascular space

b

Pancreas Mesenteric vessels Duodenum Ascending colon

Left paracolic gutter Descending colon

c Fig. 24.4 a The single, wide anterior pararenal space extends from the posterior parietal peritoneum to the anterior renal fascia. It is confined laterally by lateroconal fascia. The anterior renal fascia separates the anterior pararenal space from the perirenal and perivascular spaces. The posterior parietal peritoneum confines the anterior pararenal space anteriorly. This thin peritoneal layer is not generally visible at CT whereas fasciae are clearly evidenced if associated with abundant extraperitoneal fat. The anterior pararenal space anteriorly confines the lesser sac, mesenteric root, and transverse mesocolon. b It is laterally closed by the lateroconal fascia, which surrounds adipose tissue within the paracolic gutters. c The anterior pararenal space contains the pancreas, duodenum, ascending and descending colon, mesenteric and transverse mesocolonic roots, mesenteric vessels, lymph nodes, and abundant fat tissue. It is continuous with the symmetric ileal extraperitoneal space

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Anterior pararenal space Left iliac space

Psoas muscle Oblique muscle

Iliac muscle a

Terminal ileum Sigmoidal mesocolon

Cecum b

Posterior pararenal space

Transversalis fascia

c Fig. 24.5 a The inferior extraperitoneal or iliac space is cone-shaped and symmetrically paired. The general axis is vertical. Medially, it is limited by the ileopsoas muscle fascia and approaches the spine. Its lateral and inferior borders are the fasciae of the oblique and iliac muscles, respectively. Superiorly, the iliac space lies below the perirenal space and the kidney. It provides direct connections with the anterior and posterior pararenal spaces. b Anteriorly, the iliac space is closed by the posterior peritoneal fascia. On the right side, it is confined by the cecum, appendix, and terminal ileum, and on the left side by the sigmoidal colon and mesocolon. c The posterior pararenal space is the most posterior extraperitoneal space. Anteriorly, it is closed by the perirenal fascia and posteriorly by the transversalis fascia. This space does not contain organs, only adipose tissue

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Perivascular space Inter-renal fascia

Perivascular space, adipose tissue

Transversalis fascia

a

Common iliac vessels

Transversalis fascia

b

Aorta

Inferior vena cava

Lumboaortic lymph nodes Ureter

Extraperitoneal pelvic space c Fig. 24.6 a The central extraperitoneal space is called the perivascular space. Anteriorly, it is closed by the inter-renal fascia, which separates it from the anterior pararenal space and pancreas. The inter-renal fascia surrounds the adipose tissue that fills the perivascular space. b Inferiorly, the perivascular space joins the confluence of the iliac vessels. The transversalis fascia posteriorly closes the perivascular space and separates it from the vertebral column. c The perivascular space is a single longitudinal plane containing the abdominal aorta, with the origins of the celiac trunk, superior mesenteric artery, and renal and lumbar branches, as well as the inferior vena cava, lumbar ureters, and lumboaortic lymph nodes. All of these structures are embedded in adipose tissue that establishes continuity with adipose tissue contained in both the mesentery and the transverse mesocolonic root

Pancreas

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Stomach Gastroduodenal artery

Splenic artery

Common hepatic artery

Pancreas, tail

a

Gastroduodenal artery

Pancreas, body Superior mesenteric artery

Dorsal pancreatic artery

b

Duodenal bulb Pancreas, uncinate process

Pancreaticoduodenal artery

c

Fig. 25.1 a The pancreas is located in the anterior retroperitoneal space and is slanted, with the head lower than the tail. The pancreatic head and uncinate process are embedded in the duodenal C-loop, while the tail is often located between the stomach and spleen. Superior mesenteric vessels and the celiac trunk are pancreatic landmarks. The upper body of the pancreas is visible on the same plane as the hepatic and splenic arteries. b The body of the pancreas is on the same plane as the superior mesenteric artery. Flow in the gastroduodenal and dorsal pancreatic arteries is vertical. c The uncinate process is visible at the level of the pancreaticoduodenal artery

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Stomach Portal vein Pancreas, body Right adrenal gland

Pancreas, tail

a

Duodenal bulb

Pancreas, body

Celiac artery

Splenic vein Left adrenal gland

b

Superior mesenteric artery Pancreas, head

Pancreas, uncinate process

Duodenum

c

Fig. 25.2 a At the level of the body of the pancreas, the gastric antrum and adrenal glands are usually visible. b Flow in the splenic vein is horizontal, along the back profile of the pancreas, before the confluence with the portal vein. c Blood flow through the pancreatic head and uncinate process, the lower duodenum, and the superior mesenteric artery is vertical

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Stomach Duodenum

Pancreas, body

Superior mesenteric vein

Superior mesenteric artery

a

Portal vein Gallbladder

Pancreas, body

Pancreas, head

Pancreas, uncinate process

b Colon Portal vein

Stomach Pancreas, tail

Gallbladder

Jejunum Pancreas, head

Pancreas, body

Duodenum

c

Fig. 25.1 a Coronal reformatted image shows vertical flow in the superior mesenteric artery and vein. The body of the pancreas is visible. b The head of the pancreas, the portal vein, and the gallbladder are shown in this section. c Only a multiplanar reconstruction (MPR) curved reformatted image is able to visualize the pancreas in a single section and, at the same time, the adjacent organs (portal vein, gallbladder, stomach, duodenum, colon, and jejunum)

Adrenal Glands

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Right lobe of the liver

Inferior vena cava

Right adrenal gland

Right diaphragmatic crus

a

Left adrenal gland

Pancreas, tail

Abdominal aorta

Left diaphragmatic crus b

Left adrenal gland

Liver

Superior pole of the left kidney Right adrenal gland

c Fig. 26.1 a The right adrenal gland lies anteromedial and superior to the upper pole of the kidney, in the angle between the right lobe of the liver and the right diaphragmatic crus, just posterior to the inferior vena cava. b The left adrenal gland lies posterolateral to the aorta and is more anteromedial than superior to the upper renal pole. It is closely related to the tail of the pancreas and its vessels, the splenic artery and vein, and presents a medial surface close to the left diaphragmatic crus. On axial CT, the left adrenal gland is more often triangular, or Y-shaped. c As seen on this CT coronal reconstruction, each adrenal gland is situated immediately anterosuperior to the respective superior renal pole in the perirenal space

Kidneys and Ureters

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Right adrenal gland

Left adrenal gland

Upper pole of the kidney a

Dorsal vertebra

Abdominal aorta Left renal vein

Inferior vena cava Renal sinus

b

Superior mesenteric artery Inferior vena cava

Abdominal aorta Left renal vein

Right renal vein c

Fig. 27.1 a The two kidneys, one on each side of the spine, are located in the retroperitoneum, approximately at the level of vertebrae T12-L3, between the anterior and posterior fascia of Gerota. They are contained within a fatty capsule, with an adrenal gland situated at the top of each one. The asymmetry within the abdominal cavity caused by the presence of the liver typically results in the right kidney being slightly lower than the left, and the left kidney slightly more medial than the right. b The renal artery enters the kidney at the renal hilum, with the renal vein and ureter exiting from this site. The artery is somewhat narrower than the vein. c The renal veins connect the kidney to the inferior vena cava. Since the inferior vena cava is on the right half of the body, the left renal vein is generally longer than the right. The right renal vein is anterior to the right renal artery, while the left renal vein courses between the aorta and superior mesenteric artery to join the inferior vena cava

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Liver Upper pole of the right kidney Colon Inferior pole of the right kidney Ileopsoas muscle

a

Stomach Spleen Upper pole of the left kidney

Pancreas

Inferior pole of the left kidney Rectus muscle

b Fig. 27.2 a Sagittal views along the major axis of the kidney more clearly evidence its anatomical relationships. The anterior surface of the right kidney is related to the inferior surface of the liver and, next to the hilum, to the second portion of the duodenum. Inferiorly, the right kidney is confined by the curvature of the right colon. Posteriorly, the relationships of both kidneys with the lumbar quadrate muscle and, more medially, the psoas muscles can be appreciated. b The anterior surface of the left kidney has a direct relationship with the tail of the pancreas, its superior pole with the spleen, and the hilum with the small bowel. Both the lateral profile and the inferior pole of the left kidney are related to the descending colon

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Left renal artery

Right renal artery

Left renal vein Lumbar spine

a

Superior mesenteric artery Left renal vein

Right renal artery

Left renal artery

b

Aorta

Right renal artery

Left renal artery

Segmental artery

c Fig. 27.3 a Classically, each kidney is supplied by a single renal artery and a single renal vein, arising from the abdominal aorta and inferior vena cava, respectively. These vessels typically originate off the aorta at the level of L2, below the takeoff of the superior mesenteric artery, with the vein anterior to the artery. b The right renal artery typically demonstrates a long downwards course to the relatively inferior right kidney, traversing behind the inferior vena cava. Conversely, the left renal artery, which arises below the right renal artery and has a more horizontal orientation, takes a rather direct upwards course to the more superiorly positioned left kidney. In addition, both renal arteries course in a slightly posterior direction because of the position of the kidneys. c The main renal artery divides into five segmental arteries near the renal hilum. The first division is typically the posterior branch. The main renal artery then continues before dividing into four anterior branches at the renal hilum: the apical, upper, middle, and lower anterior segmental arteries

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Liver Spleen Renal cortex

Renal hilum

Renal medulla Psoas muscle

a

Diaphragm

Pyramids

Liver Renal medulla (pyramids)

Renal sinus

Psoas muscle

b

Renal calyx Renal calyx Renal pelvis

Renal pelvis

Lumbar vertebra

Ureter

c

Fig. 27.4 a The corticomedullary phase is characterized by intense enhancement of the renal cortex and renal columns. b In the nephrographic phase, the attenuation of the renal medulla slowly increases until this portion of the kidney becomes isoattenuated or even hyperattenuated relative to the renal cortex. c The excretory phase shows opacification of the pyelocaliceal system

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Renal pelvis Lumbar ureter

Sacrum Ureter Urinary bladder

a

Renal pelvis

Inferior vena cava

Calix

Lumbar vertebra

b Inferior vena cava

Ureter Ureter

Psoas muscle c Fig. 27.5 a Volume rendering reconstruction shows the ureters as muscular tubes that propel urine from the kidneys to the urinary bladder. The ureters arise from the renal pelvis, on the medial aspect of each kidney, before descending towards the bladder on the front of the psoas major muscle. They cross the pelvic brim near the bifurcation of the iliac arteries (which they traverse) to run posteroinferiorly on the lateral walls of the pelvis. They then curve anteromedially to enter the bladder through the back, at the vesicoureteric junction, running within the wall of the bladder for a few centimeters. b On axial scan, the ureters are situated at the pelviureteric junction. c The abdominal part of the ureter is located anteromedially, on the psoas muscle

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Left ureter

Right ureter Calyx

Psoas muscle

a

Left ureter

Right ureter

External iliac artery

Internal iliac artery Sacrum

b

Urinary bladder Left ureter

Right ureter

c

Fig. 27.6 a In this scan, the ureters are located anterior to the psoas muscle. The right ureter, in its downwards course, lies to the right of the inferior cava, while the left ureter is crossed by the left colic vessels. b The ureter crosses the pelvic brim at the level of the bifurcation of the common iliac artery. c The ureter descends along the retroperitoneal pelvic wall to the ureteral orifice located on the posterolateral wall of the bladder

Part Pelvis

III

Urinary Bladder

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Rectus muscle

Internal iliac vessels

Urinary bladder, dome

Sigmoid colon

a

Anterior wall of the bladder

Lateral wall of the bladder

Ureter Seminal vesicles

Rectum b

Ischiopubic ramus Urinary bladder Prostate Anus

c Fig. 28.1 a The urinary bladder is a muscular and distensible organ located in the pelvis. The wall of the fully distended bladder is approximately 2-3 mm thick. b As its size, position, and relationships to other organs and anatomical structures vary according to the amount of fluid it contains, the bladder must be studied in both its empty and its distended state. The bladder consists of the fundus, dome, and superior and inferior surfaces. The anterior wall of the bladder is posterior to the rectus muscles. Laterally, the obturatory muscles and vessels of the obturatory region are reconizable, and posteriorly, the ureters. c The anatomical relationships of the posterior wall of the bladder differ in males and females. In males, the bladder is related to the seminal vescicles and prostate, and in females, to the uterus

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Ileopsoas muscle

Ureter

Urinary bladder, dome

Seminal vesicle

Urinary bladder, fundus a

Prostate

Sigmoid colon Sacrum Retropubic (Retzius’) space

Seminal vesicle Rectum

Pubic symphysis b

Prostate

Fig. 28.2 a The coronal view shows the fully distend bladder surrounded by perivesicular fat. In males, the prostate abuts the base of the bladder, with the seminal vesicles related to the posteroinferior bladder wall. The superior half of the bladder is in contact with the terminal loops of the small intestine. b In sagittal view, the moderately full bladder assumes an oval form, with the long diameter directed upwards and forwards. In this condition, the bladder presents posterosuperior, anteroinferior, and two lateral surfaces, a fundus, and a dome. The sigmoid colon is posterosuperior to the bladder, with the rectum posterior. The retropubic space, also referred to as Retzius’ space, is located between the pubic symphysis and the anteroinferior wall of the bladder

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Uterus Iliac vein Iliac artery Left ovary Urinary bladder Ischiopubic ramus a

Sigmoid colon

Fundus and body of the uterus

Cervix Urinary bladder

Vagina

Rectum Retropubic (Retzius’) space b

Fig. 28.3 a The bladder is surrounded by perivisceral fat. In the female, it lies adjacent to the uterus and ovaries. b In sagittal view, the bladder is separated from the anterior surface of the uterine body by the uterovesical pouch, but below this level areolar tissue connects it to the front of the cervix uteri and the upper part of the anterior wall of the vagina. When the bladder is empty, the uterus rests upon its superior surface

Bony Pelvis

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Ilium Pubic symphysis Femoral head Acetabular cavity Femoral neck Lesser trochanter a

Anterior-superior iliac spine

Ilium Superior acetabulum

Anterior-inferior iliac spine

Greater trochanter

b

Sacrum

Ileopubic branch

Coccyx

Ischial tuberosity Pubic symphysis c

Ischiopubic branch

Fig. 29.1 a 3D-shaded surface display reconstruction is the best post-processing method to study the anatomy of the bony pelvis. The iliac wings laterally border the pelvic ring. The hip bones are connected to each other anteriorly at the pubic symphysis. The femoral head is contained in the acetabular cavity. b Parasagittal rotation demonstrates the anterior-superior and anterior-inferior iliac spines. c On sagittal view, the pubic symphysis, ileopubic branch, and ischial tuberosity are apparent, with the sacrum and coccyx seen posteriorly

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Quadrilateral sheet

Acetabular roof

a

Fovea

Acetabular notch

Quadrilateral sheet b

Anterior column

Femoral head Greater trochanter

Posterior column

c

Fig. 29.2 a The acetabular cavity is bordered above by the roof and on the medial side by the fundus of the acetabulum. b The fovea capitis is a depression in the central portion of the femoral head that is attached the ligamentum teres. c The acetabulum is limited anteriorly and posteriorly by the anterior and posterior column, respectively

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Ilium Sacroiliac joint Posterior sacral foramina

a

Ilium

Pubic symphysis

Ileopubic branch b

Ilium

Posterior column Anterior column Femoral head c

Fig. 29.3 a Coronal view shows the sacroiliac joints. The spinal roots surface through the posterior sacral foramina. b The ileopubic branch and pubic symphysis are seen in this coronal view. c Sagittal view reveals the anterior and posterior columns of the acetabula

Muscular Pelvis and Pelvic Floor

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Internal oblique muscle External oblique muscle

Transversus abdominus muscle

Psoas muscle

a

Rectus abdominus muscle

Psoas muscle Gluteus minimus muscle

Iliacus muscle Iliac wing

Gluteus medius muscle Gluteus maximus muscle b

Psoas muscle

Sacrospinous ligament

Gluteus maximus muscle

c

Fig. 30.1 a The anterior pelvic wall is formed by three muscles: internal oblique, external oblique, and tranversus abdominus. The psoas muscle runs along the lumbar vertebrae. b In the central part of the anterior pelvic wall, the rectus abdominus muscle runs vertically, from the xiphoid process to the pubic symphysis and pubic crest. c The psoas muscle, with its extrapelvic part, runs near the acetabulum and hip joint

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Pectineus muscle Internal obturator muscle

Piriformis muscle Levator hiatus muscle

Ischiorectal fossa

a

Psoas muscle

Gluteus medius muscle Gluteus maximus muscle Internal obturator muscle b

Psoas muscle Anterior column

Femoral head

c

Fig. 30.2 a The pelvic floor is bounded anteriorly by extrapelvic muscles (pectineus and piriformis), on the outside by the ileopubic branch, and inside (within the ileopubic branch) by the internal obturator muscle. The levator hiatus muscle borders the ischiorectal fossa anteriorly. b Coronal view shows the psoas muscle running along the lumbar vertebrae. The gluteus medius and maximus muscles are close to the iliac wing. c Sagittal view shows the extrapelvic part of the psoas muscle, close to the anterior column of the acetabulum and to the hip joint

Pelvic Space

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Right ovary Fallopian tube Left broad ligament

Right broad ligament

Uterus

a

Uterus Right paravesical fossa Left paravesical fossa Bladder

b

Peritoneum

Broad ligament

Uterus Left pararectal fossa Right pararectal fossa Rectum c Fig. 31.1 a The peritoneal reflections separate the pelvis into intraperitoneal and extraperitoneal compartments and form several recesses in which abnormal fluid collections may accumulate. In the female pelvic space, the anterior and posterior walls of the uterus are covered with peritoneal reflections that extend and fold laterally to form the right and left broad ligaments. These large ligaments cover the uterine round ligament and vessels, Fallopian tube, ovary, and ovarian suspensory ligament. They also form the mesosalpingeal and meso-ovarian broad ligaments. The broad ligaments pass laterally to cover the lateral pelvic wall and are directly continuous with the parietal peritoneum. The lateral surfaces of the uterus are not covered by peritoneum but confine the uterine vessels. b In both the female and the male pelvis, peritoneal reflections cover the dome of the bladder, laterally forming perivesical pouches (fossae). c Similarly, in the pelvis of both sexes, peritoneal reflections cover the anterior rectal surface, laterally forming perirectal pouches (fossae)

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Anterior parietal peritoneum

Transversalis fascia Prevesical space

a Umbilicus Umbilicovesical space

Urachus

Pubovesical ligaments b

Right paravesical fossa

Pubic symphysis

Left paravesical fossa

c Fig. 31.2 a The largest extraperitoneal recess is the prevesical space, which is located anterior to the parietal peritoneum of the anterior abdominal wall, between the transversalis fascia and umbilicovesical fascia. The latter extends from the bladder to the umbilicus, closing the prevesical space posteriorly. Inferiorly, this space is delineated by the pubovesical ligaments, which extend from the bladder base to the pubic symphysis. b The paravesical space contains the urachus vestige (present in fetal life), located within the median umbilical fold, which extends from the bladder dome to the umbilicus. c Fat tissue in the prevesical space laterally merges with connective tissue of the paravesical fossae. These pouches surround the lateral vesical walls

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Uterus Parametrial vascular plexus Parametrium

Vagina

Cervix a

Paracervical vascular plexus

Paracervix

b

Uterosacral ligament Perirectal space

c Fig. 31.3 a The anterior and posterior uterine surfaces are covered by the peritoneum and extend to form the posterior vaginal fornix. The lateral uterine surfaces are not covered by peritoneum but instead are “bare areas.” Extraperitoneal spaces connected with these uterine bare areas are filled with connective and adipose tissue, forming the parametrium. The latter is located adjacent to the lateral borders of the uterus, where the peritoneum reflects to give rise to the broad ligaments. The parametrium contains the uterine arteries and veins. b Paracervical adipose-connective tissue surrounds the cervix and contains the cervical vessels and the ureters, with the latter coursing medially to reach the bladder. The floor of the parametrium consists of cardinal ligaments, which extend as far as the pelvic walls. c The lateral margin of the parametrium forms the uterovesical ligaments, extending from the cervix to the bladder. Posteriorly, the uterosacral ligaments extend from the cervix to the sacrum. They are covered by the peritoneum, which forms recto-uterine folds that laterally confine Douglas’ pouch. These folds contain vessels and small lymph nodes

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Deferent duct

Perirectal space

a

Prevesical space

Urachus

Bladder Periprostatic space

Rectum

b

Prostate gland Periprostatic plexus Levator ani muscle Ischiorectal fossa

c Fig. 31.4 a At the level of the second to fourth sacral vertebrae, the male rectovesical space is a single peritoneal pouch located between the rectum and bladder. In the male, anterior and posterior rectovesical peritoneal folds create Denonvilliers’ fascia, which separates the prostate gland from the rectum. Reflections of the lateral umbilical fascia contain the deferent ducts. The rectum is surrounded by adipose tissue of the perirectal fossa. b The male prevesical extraperitoneal space is closed inferiorly by puboprostatic ligaments, which extend from the pubis symphysis to the prostate gland and floor of the bladder. c The periprostatic extraperitoneal space is filled with adipose and connective tissue containing the periprostatic vascular plexus. This space is laterally closed by the levator ani muscle, which confines the ischiorectal fossa. The latter contains abundant adipose tissue

Female Pelvis: Uterus, Ovaries, and Ligaments

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Uterus, body Uterus, fundus Cervix Endometrium Vagina Bladder a

Uterus, endometrium

Round ligament

Uterus, myometium

b

Iliac artery Left ovary Iliac vein Uterus Bladder

c

Fig. 32.1 a On sagittal view, the uterus is seen in the middle of the pelvis, between the bladder and rectum. It is formed by the fundus, body, and cervix. b The round ligament fixes the uterus laterally. c On coronal view, the iliac vessels (artery and vein) run close to the ovary

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Left ovary Right ovary

Uterus

a

Left ovary Right ovary Uterus

b

Left uterine artery

Right uterine artery

c

Fig. 32.2 a On coronal view, the ovaries are located in the iliac fossae and are hypointense to other structures. b This is due to the presence of follicles within the ovaries. c On maximum-intensity projection (MIP) reconstruction, the uterine artery is seen to arise from the internal iliac artery to run laterally along the uterus

Prostate and Seminal Vesicles

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Urinary bladder

Left seminal vesicle

Right seminal vesicle Rectum a

Urinary bladder Ureter

Seminal vesicle Rectum b

Prostate Internal obturator muscle

Levator ani muscle c

Fig. 33.1 a Axial view shows the seminal vesicles, or vesicular glands, as paired, simple tubular glands. Their size varies with age, being largest in men in the fifth and sixth decades of life. b The seminal vesicles are obliquely oriented, convoluted tubules that lie between the posterior surface of the bladder and the rectum. They are bordered laterally by numerous small vessels belonging to the periprostatic venous plexus. The angle between the bladder and seminal vesicle is occupied on each side by fatty tissue. c The glands are located superior and posterior to the prostate, which is a firm, partly glandular and partly muscular body about the size of a walnut and enclosed in a fibrous capsule. The prostate is perforated by the urethra. Calcifications are usually in the parenchyma of the gland, peripheral to the urethra

33 Prostate and Seminal Vesicles

203

Pubic symphysis

Prostate Levator ani muscle

Internal obturator muscle a

Rectum

Pubic symphysis Levator ani muscle Prostate b

Rectum Urinary bladder Prostate Seminal vesicles c Fig. 33.2 a Axial view of the prostate shows its anterior, posterior, and two lateral surfaces. The anterior surface measures about 2.5 cm from above downwards but is narrow and convex from side to side. It is situated about 2 cm behind the pubic symphysis, from which it is separated by a plexus of veins and a quantity of loose fat. The urethra emerges from this surface slightly above and in front of the apex of the gland. b The posterior surface of the prostate is flattened from side to side and is slightly convex from above downwards. The gland’s sheath and loose connective tissue separate it from the rectum. Its lateral surfaces are covered by anterior portions of the levator ani muscle, which is separated from the gland by a plexus of veins. c On sagittal view, the prostate is shaped like an inverted cone, with its base along that of the bladder and its apex close to the pelvic diaphragm, on the same level as the levator ani muscle. Posteriorly, the gland’s relationship with the seminal vesicles and the rectal ampulla can be appreciated