The Elbow

Ulnar nerve lesions

Sensory deficit

The palmar and dorsal cutaneus branches innervate the ulnar aspect of wrist and hand.
On the palmar side this is: The ulnar aspect of the hand and the dorsal side of the little finger and the ulnar half of the ring finger.
On the dorsal side this is: The ulnar half of the wrist; the little finger; the ring finger - except the radial half of the two distal phalanges- ; and the ulnar side of the middle finger up to the proximal interphalangeal joint.

Paraesthesia may be felt in the little finger and the ulnar side of the hand and the ring finger.

Motor ulnar palsy

Ulnar nerve palsy at the level of the elbow has serious functional consequences in wrist and hand.
Weakness of the flexor carpi ulnaris and the flexor digitorum longus of IV and V leads to a classic claw deformity.
Most problems however are caused by a paralysis of the intrinsic muscles of hand and thumb. This will result in an inability to perform a precision pinch.


Palsy of the ulnar lumbricales causes a claw deformity of the ulnar fingers	Abduction of the littel finger is weak (palsy of the abductor digiti minimi)	Flexion of the fifth metacarpal is impossible (palsy of the opponens digiti minimi.)

Palsy of the adductor pollicis ( "closing of metacarpale I in relation to metacarpale II)	Palsy of the intrinsic muscles of thumb and index fingers cause a 'terminal pinch'	Palsy of the interossei.