Carpal tunnel syndrome (CTS) is a condition in which the median nerve in the wrist is compressed. This causes numbness and pain in the fingers and hand.

What is going on in the body?

A ligament and the bones at the base of the palm of the hand, just beyond the wrist, form the carpal tunnel. Through this tunnel passes the median nerve and tendons going to the fingers and thumb. The median nerve conducts sensation from the palm side of the thumb and fingers, except for the little finger. It also carries impulses to small muscles in the hand, particularly at the palm side of the base of the thumb. If the pressure in the carpal tunnel increases enough, the median nerve is compressed.

What are the causes and risks of the condition?

CTS can be caused by anything that increases pressure on the nerve in the carpal tunnel. CTS has been associated with repetitive stress injury. This type of injury occurs when a part of the body is used repeatedly or overused. People who use computers or vibrating tools are at particular risk. Factory workers on assembly lines, or those who do repeated actions involving the wrist, may develop CTS.

Other factors can also increase a person's risk for carpal tunnel syndrome. Examples include the following:

Carpal tunnel syndrome is more common in women than in men. It is most common in middle-aged individuals.