Overflow Incontinence
Patients with overflow incontinence have a bladder that doesn't contract well or at all. The bladder fills up to capacity, then any urine that is added from the kidneys just runs out. This can be compared to overfilling a pail with water. Rarely, in women, is overflow incontinence due to obstruction of the urethra; in men this is common due to hypertrophy of the prostate. However, in women that have severe prolapse of the bladder or vagina, actual kinking of the urethra can occur.
Patients, therefore, never feel empty--in fact they are usually constantly full. Since the bladder doesn't contract these patients may push on their lower abdomen and lean forward to help compress the bladder and get urine out. (crede maneuver