Venous drainage of jejunum and ileum

The small intestine is drained by the vessels of the portal venous system. The venous drainage of the jejunum and ileum occurs through small jejunal veins and ileal veins that carry blood to the superior mesenteric vein. The superior mesenteric vein merges with the splenic vein behind the head of the pancreas, and the blood drains into the hepatic portal vein.