Middle colic vein

At a glance

English

Middle colic vein

Latin (TA2)

Vena colica media

System

Vein

Region

Trunk

Side

Single, on the midline

About the middle colic vein

Most of the transverse colon is drained by the middle colic vein. It is part of the portal system, carrying its blood via the superior mesenteric vein into the hepatic portal vein and so to the liver. It accompanies the middle colic artery, the branch of the superior mesenteric artery that supplies the same stretch of bowel.

Its tributaries begin as small veins in the wall of the transverse colon. These run back between the two layers of the transverse mesocolon and join the marginal venous arcade near the bowel, where they connect with the right colic vein towards the hepatic flexure and with the left colic vein towards the splenic flexure. Right and left branches then gather the blood and unite into the main trunk of the middle colic vein, which passes down through the mesocolon towards its root in front of the head and neck of the pancreas.

It ends in the superior mesenteric vein, usually just below the neck of the pancreas. In many people, however, it joins a short common trunk instead, the gastrocolic trunk of Henle, formed with the right gastro-omental vein and pancreaticoduodenal veins, which then enters the superior mesenteric vein. Doubled middle colic veins are also common.

The vein matters in colorectal and pancreatic surgery. When the transverse colon is removed for cancer, the middle colic vessels are divided at their origin so that the lymph nodes along them are removed too, and the vein must be followed carefully to its junction to avoid tearing the superior mesenteric vein. During operations on the head of the pancreas the middle colic vein and Henle's trunk are useful guides to the superior mesenteric vein. Its connections with the right and left colic veins also allow drainage of the colon to continue when one route is tied off.

Course and drainage

Begins at

Formed in the transverse mesocolon by right and left branches draining the transverse colon and the marginal venous arcade.

Drains into

Descends in the mesocolon to open into the superior mesenteric vein below the neck of the pancreas, often via the gastrocolic trunk.

Drains

Drains the transverse colon into the portal system.