Review of Arteries of the Large Intestine

The large intestine is a vital organ of the human digestive system, responsible for the absorption of water and electrolytes and the formation of feces. As such, it is an organ that requires a rich blood supply to sustain its functions. This article will review the anatomy of the arteries of the large intestine, their branches, and their clinical relevance.

Anatomy

The arterial supply of the large intestine is provided by the inferior mesenteric artery (IMA). This artery arises from the abdominal aorta, located just below the origin of the superior mesenteric artery. The IMA typically divides into three branches: the left colic artery, the sigmoid artery, and the ileocolic artery.

The left colic artery is the smallest branch of the IMA and supplies the transverse colon, descending colon, and sigmoid colon. This artery typically arises just below the origin of the IMA and runs posteriorly, along the left margin of the descending colon. It gives off numerous small branches that supply the transverse and descending colon before terminating in the sigmoid colon.

The sigmoid artery is the largest branch of the IMA, arising just below the left colic artery. It courses posteriorly and to the left of the descending colon before supplying the sigmoid colon. It then divides into two branches, the superior and inferior rectal arteries, which supply the rectum.

The ileocolic artery is the longest branch of the IMA and supplies the terminal ileum, the cecum, and the ascending colon. It typically arises just below the sigmoid artery and courses posteriorly and to the right of the descending colon before supplying the ileum and cecum. It then divides into two branches, the right colic artery and the ileal branch, which supply the ascending colon.

Branches

In addition to the three main branches of the IMA discussed above, there are several smaller branches that supply the large intestine. The middle colic artery arises from the ileocolic artery and supplies the transverse colon. The marginal artery of Drummond arises from the ileocolic artery and runs along the ascending and transverse colon, supplying the haustra of the colon. The appendicular artery arises from the ileal branch of the ileocolic artery and supplies the appendix. Finally, the superior hemorrhoidal artery arises from the inferior rectal artery and supplies the rectum and anus.

Clinical Relevance

The arterial supply of the large intestine is important in the diagnosis and treatment of various diseases and conditions. For example, occlusion of the IMA can result in ischemia of the large intestine, leading to abdominal pain, diarrhea, and other symptoms. In addition, occlusion of the ileocolic, left colic, or sigmoid arteries can result in ischemia of the terminal ileum, cecum, ascending colon, transverse colon, descending colon, or sigmoid colon, respectively.

The arterial supply of the large intestine is also important in the diagnosis and treatment of some cancers. For example, colorectal cancer is often detected using computed tomography (CT) scans, which are used to detect any occlusion of the IMA or its branches. In addition, some cancers can be treated using embolization, which involves the occlusion of the artery supplying the tumor. The arterial anatomy of the large intestine can thus be used to identify the artery supplying the tumor and guide embolization.

Conclusion

The arterial supply of the large intestine is provided by the inferior mesenteric artery and its branches. These arteries supply oxygenated blood to the large intestine, enabling it to perform its vital functions. In addition, the arterial anatomy of the large intestine is important in the diagnosis and treatment of various diseases and conditions, such as ischemia and colorectal cancer.