Inferior mesenteric vein
The inferior mesenteric vein is a large venous trunk located in the abdomen. It is a continuation of the superior anorectal vein, also referred to as the superior rectal vein. The inferior mesenteric vein is located in the retroperitoneum, coursing superiorly and towards the left side, while being accompanied by the inferior mesenteric artery.
The main function of the inferior mesenteric vein is to drain blood from the hindgut, a portion of the gastrointestinal tract that includes the structures from the distal transverse colon to the rectum.
|Drains from||Superior anorectal vein|
|Tributaries||Sigmoid veins, left colic vein|
|Drains to||Splenic vein|
|Drainage area||Rectum, sigmoid, descending and distal transverse colon|
This article will discuss the anatomy and function of the inferior mesenteric vein.
Origin and course
The inferior mesenteric vein arises in the lower abdomen as a continuation of the superior rectal vein that drains the rectal (hemorrhoidal) venous plexus. The inferior mesenteric vein runs retroperitoneally, ascending from its origin to the left side. Along its course, it crosses the left psoas major muscle, the left ureter and left gonadal (testicular/ovarian) vessels. Upon reaching the left side of the duodenojejunal flexure, the inferior mesenteric vein curves to the right and passes posterior to the body of the pancreas. Here, it terminates by draining into the splenic vein, which then merges with the superior mesenteric vein to form the hepatic portal vein. Occasionally, the inferior mesenteric vein may drain into the superior mesenteric vein instead, or into its confluence with the splenic vein.
Tributaries and drainage area
Along its relatively long course across the abdominal cavity, the inferior mesenteric vein receives the sigmoid and left colic veins as tributaries. Thereby, the inferior splenic vein drains blood from the rectum, sigmoid, descending and distal transverse colon. Together, the superior and inferior mesenteric veins drain the majority of the gastrointestinal tract, from the stomach to the rectum.
Explore our articles, quizzes, video tutorials and labeled diagrams to learn everything about the blood vessels of the rectum.