The superior mesenteric artery arises from the abdominal aorta just distal to the celiac trunk and has several branches to the pancreas and duodenum, two large branches that supply the proximal two thirds of the colon, and an arcade of arterial branches that supply the jejunum and ileum, terminating as the arteriae rectae of the small bowel.

The venous drainage follows a similar pattern, with the venae rectae forming a venous arcade that drains the small bowel and proximal colon through the ileocolic, middle colic, and right colic veins to form the superior mesenteric vein (Figure 1). The superior mesenteric vein and the splenic vein join and continue to the liver as the portal vein.

Figure 1. Normal Mesenteric Venous Circulation