Inferior mesenteric vein

In human anatomy, the inferior mesenteric vein (IMV) is a blood vessel that drains blood from the large intestine. It usually terminates when reaching the splenic vein, which goes on to form the portal vein with the superior mesenteric vein (SMV).

Structure
The inferior mesenteric vein merges with the splenic vein, posterior to the middle of the body of the pancreas. The splenic vein then merges with the superior mesenteric vein to form the portal vein.

Tributaries
Tributaries of the inferior mesenteric vein drain the large intestine, sigmoid colon and rectum. These include:
 * left colic vein
 * sigmoid veins
 * superior rectal vein
 * rectosigmoid veins

Variation
Anatomical variations include the inferior mesenteric vein draining into the confluence of the superior mesenteric vein and splenic vein and the inferior mesenteric vein draining in the superior mesenteric vein.

Clinical significance
The inferior mesenteric vein may be damaged during surgery on the body and tail of the pancreas. If a serious laceration occurs, the inferior mesenteric vein may be ligated, as other veins can drain the large intestine.