The inferior rectal artery (inferior hemorrhoidal artery) is an artery that supplies blood to the lower third of the anal canal below the pectinate line.

Structure

The inferior rectal artery arises from the internal pudendal artery as it passes above the ischial tuberosity. Piercing the wall of the pudendal canal, it divides into two or three branches which cross the ischioanal fossa, and are distributed to the muscles and integument of the anal region, and send offshoots around the lower edge of the gluteus maximus to the skin of the buttock. They anastomose with the corresponding vessels of the opposite side, with the superior and middle rectal arteries, and with the perineal artery. These anastomoses can be seen during angiography performed for hemorrhoidal artery embolization.

Function

The inferior rectal artery supplies oxygenated blood to the anal sphincter and the lower third of the anal canal below the pectinate line.

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