Carpal Tunnel Syndrome

Carpal tunnel syndrome is a common condition caused by compression, or entrapment, of the motor and sensory nerve in the wrist (median nerve), resulting in pain, muscle weakness, impaired reflexes, numbness, and tingling in the hand. Nerve compression is often associated with repetitive activities (e.g., typing, painting, hammering) that cause stress injury, swelling, and inflammation.Carpal tunnel syndrome is caused by compression of the median nerve. The primary risk factor is a history of another musculoskeletal disorder. The condition develops most often in people who regularly use vibrating machinery and tools and those who use their wrists repetitively, such as:

  • Accountants
  • Artists-musicians, painters, writers
  • Assembly line workers
  • Bus, taxi, and truck drivers
  • Carpenters
  • Check-out clerks
  • Computer operators and programmers

Hobbies such as rowing, knitting, needlepoint, and gardening may also increase the risk for carpal tunnel syndrome. There are other risk factors including underlying medical conditions.

The primary symptoms of carpal tunnel syndrome are pain and numbness in the thumb, index, and middle fingers that often worsen at night and may radiate to the upper arm. Symptoms usually occur near the palm of the hand. Other symptoms include muscle weakness in the hand and wrist, tingling, and impaired reflexes.In advanced cases of carpal tunnel syndrome, shrinkage (atrophy) of the fleshy area at the base of the thumb may occur.

Diagnosis of carpal tunnel syndrome is based on the history of symptoms, presence of risk factors, physical and neurological examination, and diagnostic tests. Nerve conduction velocity (NCV) and electromyography (EMG) are used to evaluate nerve and muscle function. NCV involves placing electrodes on the skin above the median nerve to monitor the speed at which an impulse travels along the nerve. EMG involves placing small electrodes into the abductor pollicis brevis muscle to detect abnormalities that may indicate that the median nerve supplying the muscle is damaged. These tests, which are often referred to as EMG/NCV studies, may reveal delayed nerve conduction in the median nerve.

Treatment for carpal tunnel syndrome involves activity modification and rest, splinting, medication (including injection therapy), and surgery.

Maintaining proper posture, body position, and technique when performing repetitive wrist movements may help to prevent carpal tunnel syndrome. It is important to relax, move around, and change positions frequently when performing any one task for an extended period of time. See a health care provider as soon as possible after symptoms develop. Essential tremor is rarely debilitating. Severe cases can usually be treated with medication.