Superior mesenteric vein is a major tributary of the portal circulation. It drains blood mainly from the jejunum and ileum of the small intestine into the portal vein.
Origin, course and termination:
The superior mesenteric vein begins at the ileocecal junction from the small veins arising from jejunum and ileum. After its origin, it runs upward on the posterior abdominal wall in the root of the mesentery of small intestine. During its course, it lies on the right side of the superior mesenteric artery.
It passes in front of the third part of duodenum and behind the neck of pancreas. Here it joins the splenic vein to form the hepatic portal vein.
The tributaries of the superior mesenteric correspond to the branches of superior mesenteric artery. These include:
- Veins from jejunum (drains blood from jejunum)
- Veins from ileum (drains blood from ileum)
- Middle colic vein (drains blood from the transverse colon)
- Right colic vein (drains blood from the ascending colon)
- Ileocolic vein (drains blood from ileum, colon and cecum)
In addition to the above tributaries, which correspond to the branches of superior mesenteric artery, the superior mesenteric vein also receives:
- Inferior pancreaticoduodenal vein (drains blood from part of pancreas and duodenum)
- Right gastroepiploic (gastro-omental) vein (drains blood from anterosuperio and posteroinferio surfaces of stomach)