left colic artery left colic artery the left colic artery is a branch of the inferior mesenteric artery distributed to the descending colon, and left part of the transverse colon. it ends by dividing into an ascending branch and a descending branch; the terminal branches of the two branches go on to form anastomoses with the middle colic artery, and a sigmoid artery (respectively).: 1196 left colic arterythe inferior mesenteric artery and its branches. (left colic visible at center right.)sigmoid colon and rectum, showing distribution of branches of inferior mesenteric artery and their anastomoses. (left colic visible at center left.)detailssourceinferior mesentericveinleft colic veinsuppliesdescending colonidentifierslatinarteria colica sinistrata98a12.2.12.071ta24292fma14826anatomical terminology structure the left colic artery usually represents the dominant arterial supply to the left colic flexure.: 1196 course the left colic artery passes to the left posterior to the peritoneum. after a short but variable course, it divides into an ascending branch and a descending branch. ascending branch the ascending branch passes superior-ward. it passes anterior to the (ipsilateral) psoas major muscle, gonadal vessels, ureter, and kidney; it passes posterior to the inferior mesenteric vein. its terminal branches form anastomoses with those of the middle colic artery; it also forms anastomoses with the descending branch (of the left colic artery).: 1196 descending branch the descending branch passes inferolaterally.: 1196 it forms anastomoses with the superior-most sigmoid artery as well as the ascending branch (of the left colic artery), thereby participating in the formation of the marginal artery of the colon.: 1196 variation the left colic artery may have a common origin with a sigmoid artery, or may arise by branching of from a sigmoid artery. occasionally, the left colic artery may arise from either the superior mesenteric artery, the middle colic artery, or the proximal-most jejunal artery; rarely, an accessory left colic artery may arise from the aforementioned arteries. an accessory left colic artery may also arise from the left colic artery itself.: 1196 clinical significance the left colic artery may be ligated during abdominal surgery to remove colorectal cancer. this may have poorer outcomes than preserving the artery. additional images superior and inferior duodenal fossæ. duodenojejunal fossa.