Ulnar nerve injury , various connections .pptx

Ulnar nerve injury

1. Ulnar nerve injury Dr. Rishav Dept. of orthopaedics

2. Applied anatomy Ulnar n arises from the C8-T1 dorsal rami and then courses along the medial aspect of arm. Passes from ant to post compartment of arm beneath the arcade & ligament of struthers . At the elbow passes through cubital tunnel under the Osborne ligament at the level of the medial epicondyle & then courses down and enters forearm by piercing between the two heads of FCU. Passes through flexor pronator muslces and at wrist it lies superficial to flexor retinaculum and then it enters into guyon’s canal.

3. Supply Muscles- FCU Ulnar half of flexor digitorum profundus Hand- Palmaris brevis, Hypothenar- opponens digiti minimi , abductor digiti minimi , flexor digiti minimi brevis Adductor pollicis Dorsal introssei Palmar introssei 3 rd & 4 th lumbrical

4. Palmar cutaneous branch arises in the middle of the forearm and supplies the skin over the hypothenar eminence Dorsal cutaneous branch of ulnar nerve- dorsal medial hand, dorsum of little finger, and half of ring finger. Superficial branch → palmar skin of little finger and ulnar half of ring finger. Articular branches are given off to the elbow joint.

5. Two nerve variants Martin gruber anastomosis ( forearm)- b/w median n & ulnar n (AIN to ulnar n) Riche- cannieu anastomosis (palm )- b/w median n & ulnar n

6. Complete anesthesia to pinpricks in the middle & distal phalanges of little finger- total division of nerve

7. Cubital tunnel syndrome- + ve percussion test over the un at the level of medial epicondyle + ve elbow flexion test - With the elbow fully flexed, the patient complains of numbness and tingling in the small and ring fingers, often within 1 minute.

8. High Ulnar Nerve Injury (lesion above elbow) Causes: Fracture medial epicondyle Supracondylar fracture extension Penetrating injuries, entrapment Muscles Paralysed: Forearm: Flexor carpi ulnaris (FCU) Medial half of flexor digitorum profundus (FDP) → ring & little finger Hand: Hypothenar muscles All interossei (palmar + dorsal) Medial 2 lumbricals Adductor pollicis

9. Motor Deficits: Loss of wrist flexion strength, with radial deviation (FCU lost). Paralysis of interossei & lumbricals -clawing, but less severe Loss of finger adduction/abduction (cannot hold paper → card test positive ). Weak thumb adduction (positive Froment’s sign ). Deformity: Mild claw hand (ulnar paradox: higher the lesion, less the clawing). Sensory Loss: Dorsum of medial 1½ fingers, Palmar aspect of little finger & medial half of ring finger.

10. Low Ulnar Nerve Injury (lesion at wrist or palm, e.g., Guyon’s canal) Causes: Lacerations at wrist Guyon’s canal syndrome ( Entrapment of the ulnar nerve in the pisohamate tunnel) Ganglion, tumors compressing nerve Muscles Paralysed: Only intrinsic hand muscles supplied by ulnar nerve: Hypothenar muscles All interossei Medial 2 lumbricals Adductor pollicis Deep head of flexor pollicis brevis

11. Motor Deficits: Flexion at DIP of ring & little intact → severe clawing of ring & little fingers. Classical claw hand

12. Nerve conduction studies -slowing in the ulnar nerve velocities across the elbow EMG shows fibrillation in the ulnar innervated intrinsic muscle.

13. Management of Ulnar Nerve Injury General Principles Aim: restore continuity, relieve compression, preserve function, and correct deformity. Depends on: level of injury (high vs low), cause (traumatic vs entrapment), duration (acute vs chronic), and functional deficit (sensory/motor loss). Conservative Management Indicated in: Mild compression neuropathies (e.g., cubital tunnel syndrome, Guyon’s canal syndrome). Neuropraxia or early cases without muscle wasting.

14. Splinting : Anti-claw splint (MCP joint kept flexed at ~30°, IPs free) to correct claw deformity and prevent contractures. Physiotherapy : Range of motion (ROM) exercises to prevent stiffness. Strengthening of preserved muscles (flexor digitorum profundus to index/middle). Nerve stimulation therapy (TENS). Occupational therapy → Training for grip, pinch, writing.

15. Surgical Management Indications: Persistent/progressive symptoms despite 3–6 months conservative care. Severe motor deficit (clawing, intrinsic muscle wasting). Lacerations or transections of the nerve. Procedures : At the Elbow (Cubital Tunnel): Simple decompression (release of Osborne’s ligament, fascia, arcade of Struthers). Anterior transposition of ulnar nerve (subcutaneous, intramuscular, or submuscular)- anterior transposition at the elbow permits closure of gaps up to 5 cm. Medial epicondylectomy (to relieve tension).

16. In Case of Nerve Injury/Transection: Primary repair (neurorrhaphy) – for clean cut injuries. Nerve grafting – when there is a segmental loss. Nerve transfers – in high/proximal injuries to restore motor function early (e.g., AIN → ulnar nerve transfer). At the Wrist (Guyon’s canal): Decompression and release of constricting structures.

17. Management of Chronic Cases / Claw Hand When intrinsic paralysis has set in: Tendon transfers to restore intrinsic hand function and correct clawing: Zancolli’s procedure - looping a slip of flexor digitorum superficialis around the opening of the flexor sheath Brand’s procedure ( extensor carpi radialis longus to intrinsic tendon transfers Index abduction is improved by transferring extensor pollicis brevis or extensor indicis to the interosseous insertion on the radial side of the finger.

18. Thank u