ABSTRACT
The arterial blood supply to the small intestine is from the superior mesenteric artery (SMA). The basic pattern of distribution of the intestinal arteries generally includes five arteries arising on the left of the SMA above the origin of the ileocolic artery and 11 below that level. Eight additional arteries usually originate from the ileal branch of the ileocolic artery (1). These intestinal vessels branch a few centimeters from the border of the intestine to form arterial arcades connecting the intestinal arteries with one another. Proximally, a single set of arcades is present; distally, there are usually several sets of arcades. These arches form the primary interconnections of the arterial supply. From arches and arcades, the vasa recta arise and pass without cross-communication to enter the intestinal wall. A complete channel may also exist from the posteroinferior pancreaticoduodenal artery that is parallel to the intestine and joins the marginal artery of Drummond of the colon. The terminal ileum, ileocecal valve, and right colon receive blood supply also from the right colic artery and ileocolic artery, often sharing a common origin, connected by the marginal artery of Drummond to the terminal branches of the SMA (Fig. 1). In 5% of the population, blood supply to these structures is guaranteed only by the ileocolic artery as the marginal artery is incomplete (Fig. 1B). The venous drainage of the small intestine is less complex than the arterial vessels, merging in the jejunal and ileal veins, and into the superior mesenteric vein and portal vein.
