Blood supply

Blood supply

The superior rectal artery is the direct continuation of the inferior mesenteric artery and is the main arterial supply of the rectum ( Figure 79.1 ). The arteries and their accompanying lymphatics lie within the loose fatty tissue in the mesorectum, surrounded by a sheath of connective tissue (the mesorectal fascia). The middle rectal artery arises on each side from the internal iliac artery and passes to the rectum in the lateral ligaments. It is usually small and often only present on one side, and divides into several branches. The inferior rectal Benjamin Alcock , 1801–?, fi rst Professor of Anatomy , Queen’s College (now University College), Cork, Ireland. Emigrated in 1859 following a resignation dispute over procurement of corpses for dissection. as it enters Alcock’s canal. It hugs the inferior surface of the levator ani muscle as it crosses the roof of the ischiorectal fossa to enter the anal muscles.

Inferior mesenteric artery Middle sacral artery Internal iliac artery Superior rectal artery Middle rectal artery Levator ani muscle Inferior rectal artery Figure 79.1 Blood supply to the rectum. The main blood supply comes from the superior rectal arteries, supplemented by middle rectal arter ies in 20% of cases. The inferior rectal arteries are derived from the pudendal vessels and supply the anal canal and lower rectum.