Which artery supplies the descending colon and sigmoid colon?

The inferior mesenteric artery is the primary vessel responsible for supplying blood to the descending colon and the sigmoid colon. This artery branches off the abdominal aorta and gives rise to several important vessels: the left colic artery and the sigmoid arteries. The left colic artery supplies the left part of the transverse colon and the descending colon, while the sigmoid arteries provide blood to the sigmoid colon.

Understanding the vascular supply to the colon is crucial in surgical practice, as it aids in surgical resections and preserving blood flow during procedures involving the colon. The other options listed do have their relevant areas of supply. For example, the superior mesenteric artery predominantly supplies the ascending colon and the proximal two-thirds of the transverse colon, while the marginal artery is an anastomotic vessel that connects branches of the superior and inferior mesenteric arteries but does not specifically supply the descending colon. The ileocolic artery, on the other hand, serves the ileum and cecum, but is not involved with the descending or sigmoid colon.