Inferior Mesenteric Vein

Origin

The inferior mesenteric vein is formed as a continuation of the superior anorectal vein in the lesser pelvis.

Course

The inferior mesenteric vein has a long retroperitoneal course. From its origin it ascends in the pelvis, anterior to the left psoas major muscle. Initially, it runs medial to the left ureter and gonadal vessels. It then passes over these structures and continues to ascend within the abdomen. At the level of the duodenojejunal flexure, the course becomes intraperitoneal, and it drains directly into the splenic vein (or the confluence of the splenic and superior mesenteric veins) (Kimura, 2000).

Tributaries

The main tributaries of the inferior mesenteric vein are the superior anorectal and sigmoid veins, and the union of the ascending and descending branch of the left colic vein. A transverse (inferior) pancreatic vein may also be present and join the inferior mesenteric vein.

Structures Drained

The inferior mesenteric vein is one of the major vessels of the hepatic venous portal system. It drains nutrient rich venous blood from the lower gastrointestinal tract into the liver, where it is processed and filtered, before entering the systemic circulation.

The inferior mesenteric vein drains mainly the large intestines via the sigmoid and left colic veins. This includes the distal third of the transverse colon, descending colon, sigmoid colon, rectum, and upper anal canal.

References

Kimura, W. (2000) 'Surgical anatomy of the pancreas for limited resection', J Hepatobiliary Pancreat Surg, 7(5), pp. 473-9.