Superior Rectal Artery
Superior rectal artery (also known as the superior hemorrhoidal artery) is the terminal continuation of the inferior mesenteric artery. The name of this terminal continuation changes as it passes over the common iliac artery to supply the mucous membrane of the rectum and upper half of anal canal.
The superior rectal artery descends into the pelvis between the layers of the mesentery of the sigmoid colon and crosses the common iliac artery to reach the rectum and upper half of anal canal.
Branches and Distribution:
Opposite the third sacral vertebra, the superior rectal artery divides into two branches. Each branch descends on either side of rectum and about 10 cm above the anus, each branch breaks up into several small branches. These branches pierce the muscular coat of the rectum and come to lie between the mucous and muscular layers. The branches are placed at regular intervals. When they reach to the level of internal anal sphincter, they form a series of loops that communicate with the middle rectal, and inferior rectal arteries.