Middle colic artery
The middle colic artery is an artery of the abdomen. It is a branch of the superior mesenteric artery that mostly supplies the transverse colon. Parts of it may be removed in different types of hemicolectomy. Structure. The middle colic artery is a branch of the superior mesenteric artery. It arises just below the pancreas. It passes inferiorly and anteriorly between the layers of the transverse mesocolon. It divides into left and right branches. The right branch anastomoses with the right colic artery. The left anastomoses with the left colic artery, a branch of the inferior mesenteric  artery (forming the arc of Riolan). This sequence of anastomoses help to form the marginal artery of the colon. The arches formed are about two fingers’ breadth from the transverse colon, to which they distribute branches. Variation. The middle colic artery may rarely originate from the splenic artery. An extra accessory middle colic artery can be found in between 10% and 20% of people. Function. The middle colic artery supplies the right two thirds of the transverse colon, and an upper part of the ascending colon. Clinical significance. In a right hemicolectomy to remove the caecum and the ascending colon , the right branch of the middle colic artery is ligated and removed. In a transverse hemicolectomy, the entire middle colic artery may need to be ligated and removed.