Types of Vaginal Prolapse
Vaginal Prolapse Relaxation
It is easier to understand uterine and vaginal wall relaxation (prolapse) if one has a working knowledge of normal anatomy. The support system of the uterus, urethra, bladder and, to some degree, the rectum is the vagina, specifically the "fascia". The vagina is a fibromuscular tube (fascia) covered with vaginal epithelium (skin). It is this fascia which is responsible for the integrity and vaginal wall strength. The fascia is the support system of the vagina. This fascia is elevated and suspended and attached to muscles and ligaments of the pelvis. A simple analogy to the vaginal wall, skin and peripheral attachment is the floor you may be standing upon. The integrity, strength or support (fascia) of the floor is the concrete or wood and the carpet (skin or epithelium) on the support is the vaginal epithelium (vagina skin). The vaginal epithelium (skin) provides very little support and primarily acts as a covering.
The floor you are standing, like the fascia, is a complete piece of material which supports anything that sits or stands upon it. The floor, as does the fascia, must be attached to something to give it a point of attachment and further strength. Peripherally the floor is attached to the walls and foundation of the house. Likewise the vagina is attached to certain ligaments and muscles so it remains supportive. Vaginal prolapse occurs when vagina loses its support and cannot maintain its shape.
"Normal" Vaginal and Uterine Support (side view)
Note the upper pubocervical fascia supports the bladder and urethra, the lower rectovaginal fascia supports the rectum. Specifically the rectovaginal fascia keeps the rectum from protruding into the vagina. Both of the pubocervical and rectovaginal fascia attach to the uterus which in turn attaches to the uterosacral ligaments. There is a continuous supportive structure (fascia) from the opening of the vagina to the uterosacral ligaments. In the situation of a vaginal prolapse, the fascia does not provide the support necessary for the vagina to maintain its natural shape.