Rectoceles and the anatomy of the posteriorvaginal wall: revisited. 
The purpose of this study was to histologically evaluate the posterior aspect of the pelvis, specifically, the relationship between the perineum, posterior vagina, anterior rectum, and all other intervening tissue.  The perineum, posterior vaginal wall, and upper part of the rectum were removed en bloc from 4 fresh cadavers without pelvic prolapse.  Length of the specimens ranged from 6 to 7.9 cm and width 3 to 4 cm.  Seven to 26 serial sections were taken from each cadaver.  Sections were stained with hematoxylin and eosin (H&E), Masson trichrome, and Verhoeff Von Gieson elastic stain.  All 4 specimens showed dense connective tissue and no plane of cleavage for 3 to 3.5 cm proximally from the posterior forchette.  Proximal to this, all 4 specimens showed space between the muscular wall of the vagina and the muscular wall of the rectum, which was composed of adipose tissue with discontinuous bands of fibrous tissue or loose areolar tissue.  This appears to be a natural line of cleavage.  Histologically, no evidence of fascia or a rectovaginal septum was identified.  Histologically, there is no evidence of a distinct fascial layer between the posterior vaginal wall and anterior wall of the rectum.  Clinically, it is the splitting of the adventitia and fibromuscular layers of the vagina that are used in defect-specific rectocele repairs to support the anterior rectal wall.