What is the difference between the superior and inferior mesenteric arteries?

The superior mesenteric artery (SMA) supplies the midgut, including structures like the small intestine and right colon. The inferior mesenteric artery (IMA) supplies the hindgut, covering the left colon and rectum.

Which organs does the superior mesenteric artery supply?

The SMA supplies the midgut organs: lower half of duodenum, jejunum and ileum, caecum and appendix, ascending colon, right 2/3 of transverse colon, and lower half of head of pancreas.

What are the main branches of the inferior mesenteric artery?

The IMA has three main branches: left colic artery to the descending colon, sigmoidal arteries to the sigmoid colon, and superior rectal artery to the rectum and upper anal canal.

How do the superior and inferior mesenteric veins drain into the portal system?

The superior mesenteric vein (SMV) joins the splenic vein to form the portal vein. The inferior mesenteric vein (IMV) typically drains into the splenic vein, but can also connect to the SMV or their confluence.

What is the clinical significance of Sudeck's critical point?

Sudeck's critical point is a weak anastomosis between the last sigmoidal artery and superior rectal artery. It is prone to ischemia if the inferior mesenteric artery is ligated, which can lead to complications in surgeries.

Where does the superior mesenteric artery originate from?

The SMA arises from the front of the abdominal aorta at the level of L1, about 1.25 cm below the coeliac trunk, behind the neck of the pancreas.

What is the Arc of Riolan and why is it important?

The Arc of Riolan is an anastomosis between the middle and left colic arteries. It helps compensate for poor blood flow in the marginal artery, preventing ischemia in areas like the splenic flexure of the colon.

SMA & IMA – Mesenteric Vessels of Midgut and Hindgut

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