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Chapter 8
195
The retroperitoneum and
gastrointestinal tract
CHAPTER CONTENTS
Normal anatomy 195
The abdominal aorta 195
Aortic aneurysm 196
The inferior vena cava (IVC) 199
Pathology of the IVC 200
The adrenal glands 201
Pathology of the adrenal glands 203
Gastrointestinal (GI) tract 206
Oesophagus and stomach 206
Appendix 206
Mesenteric ischaemia 207
Inflammatory bowel conditions 209
Malignant tumours 210
Obstruction 211
Other retroperitoneal abnormalities 212
NORMAL ANATOMY
The peritoneum is the large sheet of serous membrane
which lines the abdominal cavity and surrounds
the organs. The peritoneum has several
‘extensions’ which bind the organs together: the
mesentery, which loosely anchors the small bowel
ensuring it does not twist, the transverse mesocolon,
which attaches the transverse colon to the
posterior abdominal wall, and the greater and
lesser omentum. These projections coat the viscera
and form pouches, or sacs, within the peritoneal
cavity in which dependent fluid can collect.
The retroperitoneal space contains the kidneys
and ureters, adrenal glands, pancreas and duodenal
loop, great vessels and the ascending and descending
portions of the large bowel, including the caecum
(Fig. 8.1).
THE ABDOMINAL AORTA
The abdominal aorta can be visualized proximally
in the midline, posterior to the left lobe of the liver.
The coeliac axis and superior mesenteric artery
(SMA) are easily demonstrated in longitudinal section
(LS), arising from its anterior aspect (Fig.
8.2).
In transverse section (TS) the coeliac axis
branches, the main hepatic and splenic arteries,
may be better appreciated. Just below this level,
the origin of the renal arteries is seen.
The distal abdominal aorta, which runs more
anteriorly, and bifurcation are frequently obscured
by bowel gas in sagittal section. A coronal