What is carpal tunnel syndrome?
Carpal tunnel syndrome is a common condition that affects the hands. It is named after the part of your hand where the condition occurs - the "tunnel" formed by the ligaments in the palm of your hand (transverse carpal ligaments) and the wrist or carpal bones. Through this tunnel passes the median nerve. The median nerve is responsible for the movements of the thumb and the sensation in the thumb, index and middle fingers. When the channel through the tunnel gets too tight, the nerve is compressed causing the 'carpal tunnel syndrome'.
Who gets carpal tunnel syndrome?
The condition affects thousands of men and women but is much more common in women. It can be present in both hands but usually occurs in the dominant hand.
What causes carpal tunnel syndrome?
In most situations carpal tunnel syndrome occurs as a result of repeated hand motions that keep the wrist in a bent position or repeated forceful grasping with the hand. Examples are writing, typing, driving, using vibrating power tools, playing the piano, knitting, and needlepoint. Other associated conditions that may contribute to the development of carpal tunnel syndrome are arthritis (particularly rheumatoid arthritis), wrist injuries, diabetes, pregnancy, menopause and thyroid diseases. The median nerve is compressed in the tunnel and produces numbness and a tingling sensation in the thumb, index finger, middle finger and half of the ring finger (the half that is on the thumb side of the ring finger). Symptoms are usually worse in the early morning and at night. Carpal tunnel syndrome can cause permanent nerve and muscle damage. Even with severe symptoms, however, treatment can result in total resolution in most patients
How is the diagnosis of carpal tunnel syndrome made?
Suspicion of carpal tunnel syndrome exists when you have numbness (especially the thumb, index and middle finger) and/or tingling in your hands, particularly after extended use of your hands or at night. Your doctor will bend your wrist and hand downward for one minute. If this test reproduces your symptoms, you are likely to have carpal tunnel syndrome.
Your doctor will tap over the median nerve at your wrist. If this causes tingling in your fingers, it is likely that you have compression of the medial nerve in the tunnel.
Ultimately the diagnosis is made with nerve conduction studies. For these tests, small electrodes are placed on the fingers and a tiny shock is administered. The speed that it travels through the median nerve is recorded. Patients with carpal tunnel syndrome have slowed nerve conduction because of the compression of the nerve in the tunnel. The test has a high rate of false negatives, which means the test can be negative but the symptoms support the diagnosis and surgery may still be indicated.
