The left colic artery (Latin: arteria colica sinistra) is the first branch of the inferior mesenteric artery. It ascends in the retroperitoneal space, in front of the psoas major muscle. After a short course, the left colic artery divides into two branches - the ascending and descending branches.
The ascending branch of the left colic artery travels anteriorly to the left kidney, then enters the transverse mesocolon, passes superiorly, and supplies the upper part of the descending colon and the distal part of the transverse colon. It anastomoses with branches of the middle colic artery.
The descending branch travels inferiorly and supplies the lower part of the descending colon. It anastomoses with the first sigmoid artery.