Ulnar nerve

ulnarnerve

1. Ulnar Nerve Dr Prashant Shringi Senior Resident Neurology

2. ULNAR NERVE C 7, 8 &T1 Origin: From the medial cord of the brachial plexus. It runs downward on the medial side of the brachial artery as far as the middle of the arm . At the insertion of the coracobrachialis , it pierces the medial intermuscular septum and, accompanied by the superior ulnar collateral artery, to enter the posterior compartment of the arm. At the elbow, it passes behind the medial epicondyle . It has no branches in the arm .

3. ULNAR NERVE in the Forearm It continues downward to enter the forearm between the two heads of the flexor carpi ulnaris . It runs down the forearm between FCU and FDP. In the lower half of the forearm it lies medial to the ulnar artery.

4. Branches: Muscular : Immediately distal to the elbow joint the nerve gives off its first two muscular branches Flexor carpi ulnaris - ulnar flexor of the wrist Medial ½ of FDP- flexor of the terminal phalanges of the fourth and fifth fingers Articular : To elbow joint. Dorsal or posterior cutaneous branch : To the dorsal surface medial 1/3 rd of the hand and 1½ fingers. Palmar cutaneous branch : to supply skin of palm of hand.

5. ULNAR NERVE in the Hand Enters the palm superficial to the flexor retinaculum , passes between the pisiform carpal bone medially and the hook of the hamate carpal bone laterally ( ulnar tunnel or canal of Guyon ) Then it divides into superficial & deep branches. Superficial branch: It supplies palmaris brevis & palmar aspect of the medial 1½ fingers(sensory supply). Deep branch Runs between abductor digiti minimi & flexor digiti minimi . It pierces opponens digiti minimi . Then passes laterally within the concavity of deep palmar arch. It lies deep to the flexor tendons. It supplies 14 muscles

6. Musclar supply on hand Palmaris brevis (C8–T1 ) :A cutaneous muscle Abductor digiti minimi ( C8–Tl) : An abductor of the fifth finger Opponens digiti minimi ( C8–T1): An opposer of the fifth finger Flexor digiti minimi (C8–T1 ) : F lexor of the fifth finger Lumbricals III and IV (C8–T1 ): Flexors of the metacarpophalangeal joints and extensors of the proximal interphalangeal joints of the fifth and fourth fingers

7. Interosseous muscles (C8–Tl) : Flexors of the metacarpophalangeal joints and extensors of the proximal interphalangeal joints, four dorsal interossei are finger abductors, whereas the three palmar interossei are finger adductors Adductor pollicis (C8–T1 ) : An adductor of the metacarpal of the thumb. Deep head of the flexor pollicis brevis ( C8–Tl): F lexor of the first phalanx of the thumb.

8. Localisation of nerve leison Lesions above the Elbow: lesion of the medial cord of the brachial plexus Abnormal appearance of the hand – hypothenar eminence and interossei are atrophied and flattened Incomplete claw hand

9. Sensory findings: all three sensorybranches of the ulnar nerve are affected ( palmar,dorsal , and superficial terminal cutaneous branches)

10. Lesions at the Elbow ( Cubital Tunnel Syndrome ).

11. Ulnar nerve is most commonly compressed at the elbow in the cubital tunnel Ulnar neuropathy at the elbow often spares the flexor carpi ulnaris muscle tardy ulnar nerve palsy

12. Lesions in the Forearm: Lesions above the Elbow except that the flexor carpi ulnaris and the flexor digitorum profundus I and II muscles are often spared In a patient with surgical section of the distal ulnar nerve in the forearm, ulnar sensation in the dorsal hand was spared in relation to the superficial radial sensory innervation of the ulnar hand dorsum (“paradoxical” preservation of ulnar sensory function)

13. Lesions at the Wrist and in the Hand- Distal deep palmar motor lesion : Affects all muscles supplied by the deep palmar motor branch except the hypothenar muscles , superficial branch containing the sensory fibers and motor innervation to the palmaris brevis is not affected. Proximal deep palmar motor lesion: Affects all ulnar -innervated hand muscles, including the hypothenar muscles , with the exception of the palmaris brevis ; the superficial branch containing the sensory fibers and motor innervation to the palmaris brevis is not affected.

14. Proximal canal lesion: Affects all branches of the ulnar nerve, including the proximal and distal deep palmar motor and the superficial branches which contain the sensory fibers and motor innervation to the palmaris brevis Superficial branch lesion: Affects only the superficial branch , which is primarily sensory

15. Pseudoulnar Nerve Palsy: Pseudoulnar nerve palsy refers to isolated hand weakness apparently in an ulnar distribution that is due to contralateral cerebral infarction in the white matter of the angular gyrus of the inferior parietal lobe Palmaris brevis spasm syndrome :P rolonged use of a computer mouse and keyboard Electrophysiologic studies suggest a distal ulnar motor branch

16. Thank you