Structural anatomy of the posterior pelvic compartment as it relates to rectocele.

OBJECTIVE: This study was undertaken to define posterior compartment structural anatomy relevant to rectocele.

STUDY DESIGN: Dissection of 42 fresh and 22 fixed cadavers was supplemented by examination of histologic (n = 3) and macroscopic (n = 5) serial sections.

RESULTS: Distal posterior compartment support involves connection of the halves of the perineal membrane (urogenital diaphragm) through the perineal body, preventing downward protrusion of the lower rectum. Above this level the posterior vaginal wall is held in place by sheets of bilateral endopelvic fascia that attach each side of the posterior vaginal wall to the pelvic diaphragm. Most of these fascial fibers attach to the vaginal wall and a few fibers unite in the midline. Pelvic floor closure by the levator ani muscles relieves pressure-induced stress on the midvaginal fascial supports.

CONCLUSIONS: Midline perineal membrane union supports the distal posterior compartment and a fascial connection between the pelvic diaphragm and vagina supports the mid vagina. Muscular pelvic floor closure helps to relieve fascial stress.