Adduction of thumb Course and branches of Ulnar nerve Ulnar nerve arises from the medial cord of the brachial plexus (C8 & T1)In the arnz, no cutaneous or muscular branches arise.As the nerve enters the forearm from behind the medial epicondyle, it supplies- Flexor carpi ulnaris and- Medial half of the flexor digitorum profundusIn the distal third of the forearm, it gives off its palmar and posterior cutaneous branches.The palmar cutaneous branch supplies- The skin over the hypothenar eminenceThe posterior cutaneous branch supplies- The skin over the medial 1/3 of the dorsum of the hand and- Medial 11/2 fingersThe ulnar nerve enters the palm by passing superficial to the flexor retinaculum and divides into its superficial and deep terminal branches.The superficial terminal branch supplies - The palmaris brevis and the skin of the palmar surface of the medial 11/2 fingers, including their nail beds.The deep terminal branch supplies- all the muscles of the hand except the muscles of the thenar eminence and the first two lumbricals, which are supplied by the median nerve Branches of Ulnar NerveMuscularCutaneous- Flexor carpi ulnaris- Medial 1/3 of the palmar and dorsal- Medial half of flexor digitorum profundusaspect of hand- Palmaris brevis- Medial 1 1/2 fingers including the dorsal- Hypothenar eminence musclesdistal phalanges and nail beds.- Medial two lumbricals - All 4 dorsal interossei - All 4 palmar interossei - Adductor pollicis Injury to the Ulnar nerve Ulnar nerve is most commonly injured at the elbow, where it lies behind the medial epicondyle and at the wrist where it lies in front of flexor retinaculum.In high ulnar nerve injury at or proximal to elbow, all the muscles supplied by the ulnar nerve in the forearm and hand are paralyzed whereas in low ulnar nerve palsy, there is sparing of the forearm muscles (in flexor carpi ulnaris and flexor digitorum profundus). Sensory deficit are same in both high & low ulnar nerve injury.Clinical findings in injury at Elbow Motor- Flexion of the wrist joint results in abduction d/t paralysis of flexor carpi ulnaris- Medial border of the front of the forearm will show flattening owing to the wasting of the underlying ulnaris and profundus muscles.- The patient is unable to adduct and abduct the fingers d/t paralysis of the interossei (Palmar interossei adduct the fingers - PAD. Dorsal interossei abduct the fingers - DAB). They can be tested by Egawa's Test and Card test. Egawa's Test: (for dorsal interossei)The patient is asked to abduct his fingers, with the hand kept flat on the table, palmar surface down. Card Test: (for palmar interrossei)The patient is asked to hold a card between his two extended fingers. Examiner tries to pull the card out.- Pt. is unable to adduct the thumb because of paralysis of adductorpollicis. This can be checked by Froment's sign or the 'book test'.Froment's sign/book sign: (for adductorpollicis)The patient is asked to grasp a book between the thumb and index finger. Due to paralysis of the adductor pollicis, he does so by strongly contracting the flexor pollicis Langus and thus flexing the terminal phalanx of thumb (A normal person would keep his thumb extended).- The metacarpophalangeal joints become hyperextended because of the paralysis of the lumbricals and interossei muscles, which normally flex these joints. As the first and second lumbricals are not paralyzed, being supplied by the median nerve, the hyperextension of the metacarpophalangeal joints is most prominent in the fouh and fifth fingers. The interphalangeal joints are flexed, owing again to the paralysis of the lumbricals and interossei muscles which normally extend these joints. In long standing cases the hand assumes the characteristic 'claw' deformity (main en griffe)- Wasting of the paralyzed muscle result in flattening of the hypothenar eminence and loss of the convex curve of the medial border of the hand.- Dorsum of the hand shows hollowing between the metacarpal bones d/t atrophy of the dorsal interossei muscle.Sensory- Loss of sensations over medial 1/3 hand and 11/2 digits.Vasomotor changes- The skin areas involved in sensory loss are warmer and drier than normal because of the aeriolar dilatation and absence of sweating resulting from loss of sympathetic tone.Clinical findings in injury at WristThe small muscles of the hand will be paralyzed and show wasting except for the muscle of the thenar eminence and the first two lumbricalsThe claw hand is much more obvious in wrist lesions because the flexor digitorutn profundus muscle is not paralyzed causing marked flexion of the terminal phalanges Sensory loss and Vasomotor change are almost similar to high ulnar nerve injury..