Inferior Mesenteric Artery

Left Colic Artery
Sigmoidal Arteries
Superior Rectal Artery

The Inferior Mesenteric artery arises from the abdominal aorta at the level of L3. The named branches of the inferior mesenteric have right and left or ascending and descending branches, which contribute to arcade formation. The Left Colic artery is typically a short stem coursing across the left posterior body wall. It gives rise to an ascending and descending branch. The ascending branch anastomoses with the left branch of the middle colic artery at the left colic flexure (one critical point of collateral circulation involving the marginal artery). A variable number (1-5) of Sigmoidal arteries traverse the sigmoid mesocolon. At the level of S2-S3 the Superior Rectal artery arises as the last medial branch of the inferior mesenteric. It gives rise to a right and left branch. The middle rectal artery (internal iliac) anastomoses broadly with the superior rectal artery. The superior rectal arteries are the chief origin of the submucosal arteries, while the middle rectal arteries largely distribute to the muscular wall of the rectum.