# Venous drainage

Venous drainage

The anal veins are distributed in a similar fashion to the arterial supply . The upper half  of  the anal canal is drained by the superior rectal veins, tributaries of  the inferior mesenteric vein and thus the portomesenteric venous system, and the middle rectal veins, which drain into the internal iliac veins. The inferior rectal veins drain the lower half  of  the anal canal and the subcutaneous perianal plexus of  veins; they eventually join the internal iliac vein on each side.