The ileocolic artery is a large terminal branch of the superior mesenteric artery. It courses inferiorly towards the right iliac fossa, where it splits into a superior and inferior division. Along its course, the artery is entirely retroperitoneal. The branches of the ileocolic artery supply blood to the distal ileum, ileocecal valve, cecum and vermiform appendix, and the proximal ascending colon.
The branches of the ileocolic artery take part in the formation of the marginal artery of Drummond, which is an anastomotic channel between the branches of the superior mesenteric and inferior mesenteric arteries. This channel gives off the vasa recta, a collection of small vessels that supply the major portion of the large intestine.
This article will discuss the anatomy and function of the ileocolic artery.
|Origin||Superior mesenteric artery|
|Branches||Superior and inferior divisions; anterior and posterior cecal, appendicular, ileal, (ascending) colic branch|
|Supply||Distal ileum, ileocecal valve, cecum, vermiform appendix, proximal ascending colon|
The ileocolic artery is the most inferior branch of the superior mesenteric artery, arising from its right side. It runs inferiorly and to the right, traversing the retroperitoneum towards the caecum. On its course, it crosses over the anterior surface of the right ureter, gonadal vessels and psoas major muscle. Upon reaching the right iliac fossa, the ileocolic artery divides into its terminal branches.
Branches and supply
The ileocolic artery terminates in the right iliac fossa by splitting into a superior and inferior division. These branches anastomose with each other and give off several branches that anastomose with other branches of the superior mesenteric artery, thereby forming arterial arcades to supply the parts of the small and large intestine.
The superior division, also called the ascending branch of the ileocolic artery, runs superolaterally towards the ascending colon where it anastomoses the right colic artery and supplies the ascending colon. This anastomosis forms the proximal part of the marginal artery of Drummond through which it contributes to the supply of the rest of the large intestine. The superior division also anastomoses with the ascending colic artery, which arises from the inferior division of the ileocolic artery.
The inferior division, also called the descending branch of the ileocolic artery, runs inferiorly towards the ileocolic junction and anastomoses with the ileal branch of the superior mesenteric artery. Along its course, the inferior branch gives rise to several arteries:
- The cecal arteries usually consist of an anterior and posterior branch that supply the cecum and ileocecal valve.
- The appendicular artery descends behind the terminal ileum while suspended in the mesoappendix. It gives off a recurrent branch which anastomoses with a branch of the posterior cecal artery, supplying the appendix.
- The ileal artery anastomoses with the ileal branch of the superior mesenteric artery and supplies the terminal ileum.
- The ascending colic artery passes upwards to the ascending colon providing supply for it.
In approximately 30% of cases, the ileocolic artery gives off the right colic artery, which is usually a branch of the superior mesenteric artery. The right colic artery is then referred to as the accessory ileocolic artery. Although it typically arises individually from the superior mesenteric artery, the ileocolic artery can occasionally arise as a common trunk with other colic branches of the superior mesenteric artery.