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AAAC12 21/5/05 10:43 AM Page 32
Right colic artery
Mesentery
Ileocolic artery Ileal branch
Anterior and posterior
caecal branches
Ileocaecal fold (bloodless fold of Treves)
Meso-appendix
Appendicular artery
Fig.12.4
The blood supply of the appendix

Marginal artery
Middle colic
(from s.mesenteric) Inferior mesenteric
Left colic

Sigmoid branches

Superior rectal

Anal canal
Inferior rectal (a branch of the internal pudendal)

Fig.12.5
The inferior mesenteric artery and its branches.
Note the anastomosis with the inferior rectal artery (green) halfway down the anal canal

The abdominal aorta (Fig. 12.1) The main abdominal branches of the abdominal aorta include the:
The abdominal aorta is a continuation of the thoracic aorta as it passes • Coeliac trunk: supplies the embryonic foregut: from the lower third
under the median arcuate ligament of the diaphragm. It descends in the of the oesophagus to the second part of the duodenum.
retroperitoneum and ultimately bifurcates into left and right common • Superior mesenteric artery: supplies the midgut: from the second
iliac arteries to the left of the midline at the level of L4. The vertebral part of the duodenum to the distal transverse colon.
bodies and intervertebral discs lie behind the aorta whilst anteriorly, • Renal arteries.
from above downwards, lie its anterior branches, the coeliac plexus, the • Gonadal arteries.
lesser sac, the body of the pancreas, the third part of the duodenum, and • Inferior mesenteric artery: supplies the hindgut: from the distal
the parietal peritoneum. The main relation to the right of the abdominal transverse colon to the upper half of the anal canal.
aorta is the inferior vena cava whilst to the left lie the duodenojejunal
junction and inferior mesenteric vein.
32 Abdomen and pelvis