Removal of the uterus causes women to develop a rectocele. When the uterus is removed the bowel drifts down and fills the space previously occupied by the uterus. As the bowel moved down, it pulls the rectum down, which is known as a rectocele. When their is stool in the bowel it pushes down into the vaginal wall. Constipation is structural after hysterectomy, it is the prolapsed rectum and bowel, when there is stool in the bowel, unnaturally bulging into the wall of the vagina. There is a good description of this process on the video "Female Anatomy: the Functions of the Female Organs" at www.hersfoundation.org/anatomy.
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