The urinary sphincter, also referred to as the urethral sphincter, is a series of muscles that contract around the urethra in order to achieve bladder control. An internal urinary sphincter prevents flow of urine through the urinary tract from the bladder, and the external urinary sphincter provides additional voluntary control. Weakness or malfunction of these muscles can lead to urinary incontinence.
Function and structure of this structure differs in men and women because of a different anatomical structure and different requirements of the muscle. For example, the internal urinary sphincter in men helps prevent urine from mixing with seminal fluid during ejaculation. In women, the external urinary sphincter consists of three separate muscles, one of which also contracts the vagina. Muscles to manage urinary flow can be controlled in both men and women by contracting the pelvic floor muscles.
Urinary incontinence is one of the most common problems associated with the urinary tract muscles. This complaint is particularly common with women who have borne children. The pelvic floor muscles can become weakened or damaged in the course of pregnancy and childbirth, making it difficult for women to contract these muscles in order to control the flow of urine through the urethra. Doctors often suggest physical therapy to strengthen the pelvic floor muscles to both men and women suffering from urinary incontinence. These exercises, also called Kegel exercises, are simple to perform and can greatly increase bladder control if practiced diligently.
Men can suffer from urinary incontinence, as well, particularly after prostate surgery. In some cases, prostate surgery results in permanent intrinsic sphincter deficiency, in which the sphincter no longer functions properly. Various treatments have been developed for this condition, including physical therapy or electrical stimulation therapy to strengthen the muscles, behavioral therapy, diet therapy and other approaches. Medications are sometimes prescribed, and severe cases might require surgery.
Other approaches to managing a weakened or atrophied urinary sphincter include placement of devices within the body that can reduce bladder leakage. Women can use pessaries, which are placed in the vagina and press against the urethra to hold it closed. Men sometimes are fitted with an artificial sphincter, which is implanted within the body and controlled through a pressure pump located in the scrotum. Additional surgical approaches include creating an internal sling to help hold the urethra closed or a bladder neck suspension procedure that adds additional support to the neck of the bladder.