Carpal tunnel syndrome is due to compression of the median nerve in the wrist. The median nerve supplies sensation to the palm side of the thumb, index, and middle fingers and the thumb-side of the 4th finger. This nerve also controls the movement of the thumb. The median nerve travels through a narrow space in the wrist called the carpal tunnel with the transverse carpal ligament forming the roof of the tunnel. Swelling in the tunnel causes compression of the median nerve within this tunnel resulting in the symptoms. Repetitive hand movements may increase the likelihood of developing this disorder. It is more common in women than men, is seen more commonly in people with rheumatoid arthritis and diabetes, and most often occurs after age 30.