Middle anorectal artery

The middle anorectal artery (middle rectal artery) is an unconstant (35 to 60%of cases) traditionally described as branch from the anterior division of the internal iliac artery but in most cases*, the middle rectal artery originates from the internal pudendal artery (50.3%**) or inferior gluteal artery. The other origins of the middle rectal artery include the gluteal pudendal trunk, inferior vesical artery, internal iliac artery, obturator artery, and the prostatic artery, and the pelvic vasculatures in these cases also presented variability. 

The middle rectal artery courses inferiorly across the lesser pelvis, and enters the mesorectum where it is ensheathed by fascia along with the branches of the inferior hypogastric plexus and are sometimes together referred to as the lateral rectal ligaments.

The middle rectal artery then continues vertically, before taking a 90° turn to transversely approach the lower rectum, where it splits into several terminal branches forming weak anastomoses with the superior and inferior anorectal arteries, as well as the median sacral artery. The branches of the middle rectal artery supply the middle and lower portions of the rectum.

The middle rectal artery sometime gives rise to several other branches, such as vaginal branches in females prostatic and seminal branches in males.

The middle rectal artery has a significant variability in its presence, origin, and course. It is present in approximately 60% of individuals, with a higher prevalence observed in cadaveric studies. The middle rectal artery can be unilateral or bilateral, with bilateral presence reported in about 21-57% of cases.