Inferior mesenteric artery

Arteria mesenterica inferior

CardiovascularBlood vesselsAbdomenLeft side

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What it is

Arises from the front-left of the aorta at L3, about 4 cm above the bifurcation, and runs down and to the left behind the peritoneum, giving the left colic and sigmoid arteries and ending as the superior rectal artery in the pelvis.

Function

Supplies the hindgut: the distal third of the transverse colon, descending and sigmoid colon and upper rectum.

Size

~4 mm diameter.

Clinical note

Often sacrificed during abdominal aortic aneurysm repair because the marginal artery along the colon keeps the gut alive; the splenic flexure is a watershed prone to ischaemic colitis.