A spos-person presents with laceration of wrist but with no vascular injury. On examination, a structure lateral to flexor digitorum superficialis is found to be injured. What action he most likely cannot perform (JIPMER May 2019)
- Whenever we find laceration of wrist, most commonly damaged nerve is median nerve. (sometimes - ulnar nerve)- As the question is stating that lateral to flexor digitorum superficialis is injured, it is clearly a case of median nerve injury.- Flexor digitorum superficialis tendons (for folding is fingers) - pass deep to flexor retinaculum/ Transverse carpal ligament.- Deep to that median nerve is also passing just lateral to flexor digitorum superficialis tendon.- Median nerve supplies thenar muscles (like abductor pollicis brevis, opponens pollicis) & also give cutaneous supply to 31/2 fingers skin.- In median nerve injury, there would be paralysis of opponens pollicis resulting in problem of thumb opposition - Sometimes, wrist laceration lead to ulnar nerve injury.* Ulnar nerve & ulnar aery runs superficial to flexor retinaculum in Guyon's canal * Inside Guyon's canal, it divides into superficial & deep branches.* Superficial branch - gives 11/2 fingers skin supply* Deep branch - Supplies Hypothenar muscles like Digiti minimi muscles, all interossei & 2 lumbricals.- These are lost in ulnar nerve injury- Ulnar aery forms superficial palmar arch- Radial aery running with radius bone, become content of anatomical snuff box & gives deep palmar arch.- Abduction to 2nd digit - Need dorsal interossei - supplied by ulnar. N- Adduction of 2nd digit - Need palmar interossei - supplied by ulnar. N (PADD)- Flexion of thumb - done by flexor pollicis longus - supplied by anterior interosseous nerve which is branch of median nerve
Abduction of 2nd digit
Adduction of 2nd digit
Opposition of thumb
Flexion of thumb
JIPMER 2019