Superior mesenteric vein
Vena mesenterica superior
The large vein draining the small intestine and right colon, which joins the splenic vein behind the pancreas to form the portal vein.
At a glance
- English
- Superior mesenteric vein
- Latin (TA2)
- Vena mesenterica superior
- System
- Vein
- Region
- Trunk
- Side
- Single, on the midline
About the superior mesenteric vein
The superior mesenteric vein collects blood from the territory of the superior mesenteric artery: the small intestine from the duodenum onwards, the caecum and appendix, the ascending colon and most of the transverse colon. Because this blood is rich in absorbed nutrients, the vein is one of the two main sources of the hepatic portal vein.
It begins in the right iliac fossa from veins of the terminal ileum, caecum and appendix, and runs upwards in the root of the mesentery on the right side of the superior mesenteric artery. Along this course it receives the jejunal and ileal veins from its left, and the ileocolic, right colic and middle colic veins from its right. Near its upper end it also receives the inferior pancreaticoduodenal vein and, commonly through a short trunk shared with colic veins, the right gastro-omental vein. The inferior mesenteric vein ends in it in some people, though more often in the splenic vein.
Ascending, the vein crosses in front of the third part of the duodenum and the uncinate process of the pancreas. Behind the neck of the pancreas it joins the splenic vein, and the portal vein formed there continues up behind the first part of the duodenum to the liver.
The vein matters in several clinical settings. Thrombosis of the superior mesenteric vein causes congestion and, in severe cases, infarction of the bowel. In pancreatic cancer, whether a tumour involves this vein at the neck of the pancreas is central to deciding if the tumour can be removed. Its position to the right of the artery is a useful check on imaging: when the vein lies to the left of the artery, malrotation of the gut should be suspected.
Course and drainage
- Begins at
- Begins in the right iliac fossa from veins of the terminal ileum, caecum and appendix.
- Drains into
- Joins the splenic vein behind the neck of the pancreas to form the hepatic portal vein.
- Drains
- Drains the small intestine, caecum, appendix, ascending colon, most of the transverse colon and part of the pancreas and stomach.
Anthromica
See the superior mesenteric vein where it really sits, with every layer of the body around it.
- Every layer, one body. Peel from muscle to bone, nerve, vessel and organ, and turn it any way.
- English and Latin. Every structure named the way your exam names it.
- Quiz until it sticks. Short drills on the structures you keep missing.
Free to start. No card.
