There are a number of predisposing causes of uterine prolapse that permit the descent to progress after the uterus has begun to fall--namely: Relaxation of the uterine ligaments that results from too frequent parturition, from old age, or from tissue-weakness which is part of a general condition, the uterine ligaments sharing the general feebleness of the other tissues and structures of the body; relaxation, loss of rigidity, or muscular weakness of the abdominal parietes, which diminishes the retentive power of the abdomen; diminution of the cellular tissue and the fat of the pelvis, such as occurs in wasting disease or in old age. Anything that suddenly increases the intra-abdominal pressure, such as lifting a heavy weight, may cause acute prolapse of the uterus. In some cases the uterus has suddenly protruded from the body as a result of heavy lifting. In cases of this character it is probable that the muscular supports of the perineum have been weakened from some cause, or that the sudden increase of abdominal pressure drives the uterus downward before the perineal muscles have time to contract and close the vaginal outlet. In such cases there is also present rupture of the uterine ligaments. Constant violent coughing has produced uterine prolapse in a similar way. Extreme uterine prolapse sometimes occurs in a nulliparous woman in whom the perineal supports are naturally weak. In such women there exists a condition of relaxation identical in results with subcutaneous laceration of the perineum. Anything that increases the specific gravity of the uterus will make it sink somewhat lower in the pelvis. Subinvolution, congestion from inflammation, or retroflexion may do this. In such cases, however, the prolapse never becomes extreme, rarely extending beyond a slight sinking of the uterus. In most cases uterine prolapse takes place slowly. Sometimes many years are necessary for the development of complete prolapse. The equilibrium of the pelvic contents is destroyed by one of the causes already mentioned. The uterus falls through a certain distance before the uterine ligaments become suspensory. Then, however, its further descent is impeded. If the original cause continues to act, the uterine ligaments become stretched and the descent of the uterus gradually progresses, impeded to a varying degree also by the retentive power of the abdomen and the cellular tissue and other pelvic attachments. As the uterus descends, the vaginal walls attached at the cervix are dragged down with it, so that when the prolapse becomes complete the vagina is turned inside out (Fig. 67).