Median nerve injury at wrist, is commonly tested by:
Injury or compression of median nerve at wrist (eg carpel tunnel syndrome) can be tested by 1. Pen test for loss of action of Abductor pollicis brevis 2. Ape thumb deformity Q (adducted posture of thumb) 3. Loss of opposition & abduction of thumb Q (d/ t wasting of thenar muscles) 4. Sensory loss - lateral 31/2 of digits & 2/3 palm (autonomous zone is tip of index & tniddle finger) Abductor pollicis longus is supplied by posterior interosseous nerve (br. of radial nerve)Q; so abduction of thumb is not completely lost.
Contraction of abductor pollicis brevis
Contraction of flexor pollicis brevis
Loss of sensation on palm
Loss of sensation on ring finger