The median nerve provides feeling and movement to the "thumb side" of the hand (the palm, thumb, index finger, middle finger, and thumb side of the ring finger).
The area in your wrist where the nerve enters the hand is called the carpal tunnel. This tunnel is normally narrow, so any swelling can pinch the nerve and cause pain, numbness, tingling or weakness. This is called carpal tunnel syndrome.
Carpal tunnel syndrome is common in people who perform repetitive motions of the hand and wrist. Typing on a computer keyboard is probably the most common cause of carpal tunnel. Other causes include:
- Assembly line work
- Use of tools (especially hand tools or tools that vibrate)
- Sports such as racquetball or handball
- Playing some musical instruments
The condition occurs most often in people 30 to 60 years old, and is more common in women than men.