What is Wrist Drop?
(A) Definition : Paralysis of the extensor of wrist. There will be difficulties in extension of wrist and fingers. In an attempted extension of fingers, there will be flexion of MCP joints and extension of interphalangeal joints due to unopposed action of lumbricals and interossei. (B) Method of testing : Ask the patient to make a fist and try to flex the wrist foreibly against his effort to maintain the posture. Normally, it is almost impossible to flex the wrist overcoming the patient’s wrist extensors. But in wrist drop, patient’s wrist will be very easily flexed by the examiner. (C) Aetiology : 1) Radial nerve palsy 2) Lead neuropathy, and 3) Other peripheral neuropathies Identification points for an aetiological diagnosis : Same as described in the chapter on “Wasting of the small muscles of hands” * Never forget to palpate the ulnar nerve in the elbow and to examine trophic changes in the fingers in a patient with claw hand or wasting of the small muscles of hands.
