Inferior mesenteric vein
Vena mesenterica inferior
Also known as: IMV
The inferior mesenteric vein drains the hindgut. It begins as the superior rectal vein, ascends behind the peritoneum to the left of the duodenojejunal flexure and usually joins the splenic vein behind the pancreas.
Overview
The vein begins as the superior rectal vein, which joins the middle and inferior rectal veins of the systemic circulation in the wall of the rectum. It ascends lateral to the inferior mesenteric artery and passes beside the duodenojejunal flexure, in the paraduodenal fold. Most often it ends in the splenic vein. In other people it ends in the superior mesenteric vein or at the junction where the portal vein forms.
Anatomy
- Tributaries
The superior rectal, sigmoid and left colic veins.
Function
- Drains the descending colon, sigmoid colon, rectum and upper anal canal into the portal system.
Clinical significance
Surgical landmark
The inferior mesenteric vein is divided at the lower border of the pancreas to free the splenic flexure during left-sided colon and rectal resections.
Rectal varices
In portal hypertension, the connections between the superior rectal veins (portal) and the middle and inferior rectal veins (systemic) can dilate to form anorectal varices.
Compiled from standard anatomy and physiology references — see the Cardiovascular System sources. For education only; not medical advice.