The most common physical findings in a patient with median nerve compression at the wrist (carpal tunnel syndrome) are:

C. A positive percussion test at the wrist and a positive wrist flexion test producing paresthesias at the thumb, index, and long fingers.

DISCUSSION: While patients with carpal tunnel syndrome often complain of subjective symptoms such as numbness of the thumb, index, and long fingers, objective decreased sensibility is not usually present. Testing with von Frey filaments produces the most sensitive results. Decreased light touch is noted before decreased two-point discrimination. Dryness of the skin in the median nerve distribution is evident with severe injury to the nerve but not in the routine carpal tunnel syndrome. Although the abductor pollicis brevis and opponens pollicis are supplied by the motor branch of the median nerve, atrophy of these muscles is not seen until long-term median nerve compression has occurred. Symptomatic carpal tunnel syndrome without evidence of thenar atrophy has a greater frequency than the more severe median nerve compression, with demonstrable thenar atrophy. Percussion over the median nerve at the wrist producing paresthesias distally in the distribution of the median nerve and paresthesias caused by wrist flexion are two of the most common signs of median nerve compression at the wrist. Although patients with carpal tunnel syndrome intermittently complain of weak grip and dropping objects, cramping of the hand while writing and difficulty writing are not routine symptoms of this condition.