Superior mesenteric vein
Vena mesenterica superior
Also known as: SMV
The superior mesenteric vein drains the midgut. It runs in the root of the mesentery to the right of the superior mesenteric artery and joins the splenic vein behind the neck of the pancreas to form the portal vein.
Overview
The vein ascends in the root of the mesentery, to the right of the SMA. It crosses in front of the third part of the duodenum and the uncinate process of the pancreas, then passes behind the pancreatic neck. Its tributaries match the branches of the SMA, plus the right gastro-omental vein. Normally the SMV lies to the right of the SMA. If that relationship is reversed on imaging, intestinal malrotation is suspected.
Anatomy
- Tributaries
The jejunal, ileal, ileocolic, right colic, middle colic, inferior pancreaticoduodenal and right gastro-omental veins.
Function
- Drains the small intestine, caecum, appendix, ascending colon and transverse colon, carrying absorbed nutrients to the liver.
Clinical significance
Mesenteric venous thrombosis
Mesenteric venous thrombosis is an uncommon cause of acute mesenteric ischaemia. It is associated with hypercoagulable states, portal hypertension and abdominal inflammation, and it is treated with anticoagulation.
Pancreatic cancer resectability
Whether a pancreatic head cancer can be removed (Whipple operation) depends largely on how much it involves the SMV and portal vein.
Compiled from standard anatomy and physiology references — see the Cardiovascular System sources. For education only; not medical advice.