<prompt> Median nerve injury at wrist, is commonly tested by:Contraction of abductor pollicis brevisContraction of flexor pollicis brevisLoss of sensation on palmLoss of sensation on ring finger  <response>: 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 312 of digits 23 palm autonomous zone is tip of index tniddle finger Abductor pollicis longus is supplied by posterior interosseous nerve br. of radial nerveQ; so abduction of thumb is not completely lost. 