How is the left colon primarily supplied with blood?

The left colon is primarily supplied with blood via the inferior mesenteric artery. This artery branches off from the abdominal aorta and provides the major blood supply to the distal portion of the colon, which includes the descending colon, sigmoid colon, and part of the rectum. The inferior mesenteric artery gives rise to several important branches: the left colic artery, which supplies the descending colon, and the sigmoid arteries, which supply the sigmoid colon.

While collateral circulation can occur between the branches of the inferior mesenteric artery and those of the superior mesenteric artery, the primary source of blood for the left colon remains the inferior mesenteric artery. The celiac trunk primarily supplies blood to the upper part of the gastrointestinal tract, including the stomach, duodenum, liver, and spleen, while the superior mesenteric artery primarily supplies the midgut structures like the small intestine and part of the large intestine (up to the transverse colon). Thus, the blood supply to the left colon is distinctly associated with the inferior mesenteric artery.