Parturition is probably the most frequent cause of retroversion and retroflexion of the uterus. If the woman leaves her bed or goes to work too soon after miscarriage or labor, many conditions are present that favor retrodisplacement of the uterus. The uterus is larger and heavier than normal, as a result of imperfect involution: the uterine ligaments are lax; the vagina and the vaginal orifice are relaxed, and the support of the pelvic floor is consequently deficient; the abdominal walls are relaxed and the retentive power of the abdomen is diminished. It will be remembered that these are the causes that favor prolapse of the uterus; in fact, a slight degree of uterine prolapse usually accompanies such cases of retrodisplacement. A certain amount of retroversion must always exist before the uterus can pass along the vagina. It must turn backward, so that its axis becomes parallel to the axis of the vagina. Retroflexion occurring after miscarriage or labor is sometimes the result of unequal involution in the uterine walls. If the involution takes place more completely in the posterior than in the anterior wall of the uterus, a bending back, or a retroflexion, will occur. Such inequality of involution may result from inflammation about the site of the placenta. Retroflexion is a disease of the parous woman, as anteflexion is a disease of the single and the sterile woman. Retroversion may be a direct result of laceration of the perineum. When the pelvic floor is destroyed and the posterior vaginal wall begins to prolapse, it drags upon the posterior wall of the cervix, and may in this way turn the uterus backward. Retroversion also results from traction of inflammatory adhesions in the pelvis. Cases of chronic inflammation of the Fallopian tubes accompanied by inflammation of the pelvic peritoneum present adhesions between the posterior wall of the uterus and the hollow of the sacrum; these adhesions drag the uterus backward (Fig. 89). [Illustration: FIG. 89.--Retroversion of the uterus, with adhesions binding it to the anterior wall of the rectum and the hollow of the sacrum.] In cases of retroversion and retroflexion of the uterus serious derangement of the circulation results. A state of passive congestion follows interference with the venous supply. This congestion produces some enlargement of the uterus and chronic congestion or inflammation of the endometrium. Consequently, in all old cases of retrodisplacement endometritis is an accompaniment. Retroversion of the uterus causes traction on the vesico-uterine connection, and the neck of the bladder is dragged upon; for this reason irritability of the bladder, characterized by frequent and perhaps painful micturition, is often present in cases of retroversion. It is not uncommon to see women who have received treatment directed to the bladder for conditions of this kind that disappear immediately when the uterus is restored to the normal position.