Introduction

Introduction

Urinary incontinence is the inability to control urination. It may be temporary or permanent, and can result from a variety of problems in the urinary tract. Urinary incontinence is generally divided into four groups according to the problem involved:

• Stress incontinence
• Urge incontinence
• Overflow incontinence
• Functional incontinence

Often, more than one type of incontinence is present. Approximately 40% of all incontinence cases fall into more than one category. A variety conditions may cause incontinence. Because incontinence is a symptom, rather than a distinct disease, it is often hard to determine its cause.

Normal Urination

The urinary system helps to maintain proper water and salt balance throughout the body:

• The process of urination begins in the two kidneys, which process fluids and dissolve waste matter to produce urine.
• Urine flows out of the kidneys into the bladder through two long tubes called ureters.
• The bladder is a sac that acts as a reservoir for urine. It is covered with a membrane and enclosed in a powerful muscle called the detrusor. The bladder rests on top of the pelvic floor. This is a muscular structure similar to a sling running between the pubic bone in front to the base of the spine.
• The bladder stores the urine until it is eliminated from the body via a tube called the urethra, which is the lowest part of the urinary tract. (In men it is enclosed in the penis. In women it leads directly out.)
• The connection between the bladder and the urethra is called the bladder neck. Strong muscles called sphincter muscles encircle the bladder neck (the smooth internal sphincter muscles) and urethra (the fibrous external sphincter muscles).

Click the icon to see an animation about urination.

The Process of Urination

The process of urination is a combination of automatic and conscious muscle actions. There are two phases: the emptying phase and the filling and storage phase.

The Filling and Storage Phase. When a person has completed urination, the bladder is empty. This triggers the filling and storage phase, which includes both automatic and conscious actions.