Embryology and anatomy of the anorectum - Basis of surgery

The rectum is a pelvic organ confined in the posterior compartment of the p elvic cavity, presenting a difficult approach in its subperitoneal portion. in this article, the morphology is presented, with a special interest in t he remedies used in rectal surgery. The rectal and perirectal fasciae and t he mesorectum are described with references to oncologic surgery. The auton omic supply of the rectum-with description of the pelvic splanchnic nerves, superior hypogastric plexus with presacral anal and hypogastric nerves, an d the inferior hypogastric plexus-is described with respect to the urogenit al branches during rectal excision. The scanner, endorectal ultrasound, and MR imaging permit good evaluation of tumor staging.