Superior rectal artery
The superior rectal artery (superior hemorrhoidal artery) is a direct pelvic continuation of the inferior mesenteric artery. The superior rectal artery arises when the inferior mesenteric artery passes the pelvic brim (the edge of the pelvic inlet).
The superior rectal artery runs in the mesorectum and terminates by dividing into two terminal branches. These branches descend across the sides of the rectum, providing supply for its superior two-thirds.
This article will discuss the anatomy and function of the superior rectal artery.
|Origin||Inferior mesenteric artery|
|Branches||Two unnamed terminal branches (Left and Right)|
|Supply||Upper two this of the rectum|
The superior rectal artery arises from the inferior mesenteric artery as its continuation crosses over the left common iliac vessels and below the pelvic brim. The superior rectal artery continues its course in the inferomedial direction, towards the midline. At the level of the third sacral vertebra in the midline, it enters the mesorectum and divides into two terminal branches.
On its path through the mesorectum (the fat tissue surrounding the rectum) the artery is accompanied by the same-named vein and its tributaries. The artery terminates by dividing into two (or more) terminal branches.
Branches and supply
The superior rectal artery usually gives off two terminal branches that descend across both (left and right) sides of the rectum. The right branch is usually larger in diameter and often provides a branch for the posterior aspect of the rectum. Both branches traverse the outer layer of the rectal wall and reach the submucosa. They provide abundant blood supply for the major part of the rectum, as far inferiorly as the internal anal sphincter.
Learn more about the blood vessels of the rectum with our articles, videos, labeled diagrams and quizzes.
In approximately 10% of cases, the superior rectal artery ends in a trifurcation, providing three terminal branches.