ABSTRACT
Superior and Inferior Mesenteric Vasculature The superior mesenteric artery supplies the whole length of the small bowel except the superior part of the duodenum, the cecum, the ascending part of the colon, about one-half of the transverse part of the colon, and the left colon. It arises about 2 cm below the celiac artery and passes down across the uncinate process of the pancreas (Fig. 1). Its branches are the posterior and anterior (superior and inferior) pancreaticoduodenal arteries, the jejunal and ileal arteries, and the middle colic artery, which arises below the pancreas and passes between the layers of the transverse mesocolon, where it divides into a right and a left branch. The right branch anastomoses with the right colic artery. The left branch of the middle colic artery anastomoses with the left colic artery, a branch of the inferior mesenteric artery, forming an arcade along the mesenteric border, also named the marginal artery of Drummond. Finally, the superior mesenteric artery gives rise to the right colic artery and the ileocolic artery, which is the lowest branch arising from the concavity of the superior mesenteric artery. The superior mesenteric artery is accompanied by the superior mesenteric vein, which lies to its right side ascending between the two layers of the mesentery, and it is surrounded by the superior mesenteric plexus. The superior mesenteric vein joins the splenic vein to form the portal vein behind the neck of the pancreas (Fig. 2).
