A patient tries to make a fist but the index and middle finger remain partially extended. The nerve most probably involved is
Answer: (a) Median nerve.MEDIAN NERVE INJURY* When the median nerve is severed in the elbow region, flexion of the proximal interphalangeal joints of the lst-3rd digits is lost and flexion of the 4th and 5th digits is weakened.* Flexion of the distal interphalangeal joints of the 2nd and 3rd digits is also lost.* Flexion of the distal interphalangeal joints of the 4th and 5th digits is not affected because the medial part of the FDP is supplied by the ulnar nerve.* The ability to flex the metacarpophalangeal joints of the 2nd and 3rd digits is affected because the digital branches of the median nerve supply the 1st and 2nd lumbricals.* Thus, when the person attempts to make a fist, the 2nd and 3rd fingers remain partially extended (hand of Benediction).* Thenar muscle function (function of the muscles at the base of the thumb) is also lost, as in carpal tunnel syndrome.* When the anterior interosseous nerve is injured, the thenar muscles are unaffected, but paresis (partial paralysis) of the flexor digitorum profundus and flexor pollicis longus occurs.* When the person attempts to make the "okay" sign, opposing the tip of the thumb and index finger in a circle, a "pinch" posture of the hand results instead owing to the absence of flexion of the interphalangeal joint of the thumb and distal interphalangeal joint of the index finger (anterior interosseous syndrome)
Median nerve
Musculo-cutaneous nerve
Radial nerve
Ulnar nerve
Upper Extremity