Last updated: 11/24/2009

The diagnosis of carpal tunnel syndrome most commonly occurs because the individual seeks medical advice for numbness and tingling in the hand, especially while holding a telephone, newspaper, or holding onto the steering wheel, or has experienced...

dropping objects. A thorough medical and medication history and a physical examination, especially for checking the nerve pathway functioning in the arms and hands, are essential components of a full diagnostic workup for carpal tunnel syndrome. It is important to be able to rule out other medical conditions such as a pinched nerve in the neck, which may present with similar symptoms. A complete account of symptoms, including which fingers are involved, is important because the median nerve, the nerve involved in carpal tunnel syndrome, does not innervate the little finger. The timing of the symptoms is also important, because it indicates what activities set off the symptoms, such as while reading a book or having the hands placed on the steering wheel. Symptoms often occur at night because the hand gets set in a certain position for extended periods of time. Many people find that their hand is numb when they wake up in the morning, or that they wake up during the night with pain in the affected hand. To get relief, the individual may hang the hand off the bed, rub the hand, or shake it until the tingling goes away. Since, for many sufferers, the symptoms are worse at night than during the day, it may take time to associate the symptoms with the problem causing them. For some people, the symptoms come on, especially at first, only at work, because that is where the hand has to exert more than usual force in an awkward position. For others, the symptoms may come on when engaging in a hobby such as painting, gardening, knitting, woodworking, lifting weights, or playing a musical instrument. What begins as periodic symptoms may progress to constant symptoms, and mundane tasks such as unscrewing a bottle top or turning a key in a lock become extremely painful, or even impossible to perform. The doctor will want to try to elicit the symptoms by placing the hands in the same position as when the symptoms come on naturally.

Carpal tunnel syndrome is sometimes referred to as entrapment neuropathy, which means that a nerve, in this case the median nerve, is entrapped or compressed. In carpal tunnel syndrome, the median nerve is compressed, usually by swelling and inflammation, as it passes from the forearm into the hand through the carpal tunnel. The compression puts pressure on the nerve, which is what elicits the tingling and numbness felt by the patient. Compression can arise from a condition that causes the carpal tunnel to become smaller or narrower, or by something such as fluid retention, which would increase the volume inside the tunnel. In addition to trying to assess what nerve is involved in the problem, the doctor will want to see if strength in the hand has been affected. As part of the neurological exam, the doctor may tap at the base of the crease of the wrist. If this tapping brings on tingling in all the fingers except the pinkie, it is said that the Tinel's sign was positive. A positive Phalen test occurs when the two hands are placed back-to-back and held in that position for 60 seconds, bringing on symptoms. By extending the hands out of that position, symptoms are relieved. If these tests are positive, the doctor may want to order nerve conduction studies, although it is possible for conduction tests to be normal when the individual suffers from carpal tunnel syndrome.