A posterior prolapse occurs when the thin wall of fibrous tissue (fascia) that separates the rectum from the vagina weakens, allowing the vaginal wall to bulge. Posterior prolapse is also called a rectocele (REK-toe-seel) because typically, though not always, it's the front wall of the rectum that bulges into the vagina.
Childbirth and other processes that put pressure on the fascia can lead to posterior prolapse. A small prolapse may cause no signs or symptoms. If a posterior prolapse is large, it may create a noticeable bulge of tissue through the vaginal opening. Though this bulge may be uncomfortable, it's rarely painful.
If needed, self-care measures and other nonsurgical options are often effective. In severe cases, you may need surgical repair.