Approach

• Expose elbows
• Ask patient to place hands palm upwards on pillow

1. Inspect
   • Note claw hand appearance - paralysis of lumbricals and interossei (and unopposed action of long flexors and extensors - causes flexed deformed little finger and ring fingers)
   • Examine the palm - note wasting of hypothenar muscles (all hypothenar muscles are supplied by the median nerve)
   • Ask patient to turn hand over and observe guttering between metacarpals as interossei are wasted (best seen in 1st dorsal webspace)
2. Sensory assessment
   • Autonomous area over middle and distal phalanges of little finger
3. Motor assessment
   • Test palmar interossei (adducts fingers) by asking patient to hold a piece of paper between two fingers while you attempt to pull it away
   • Dorsal interossei - spread fingers
   • Assess for weakness of flexor digitorum profundus to the ring and little fingers
   • Froment sign (for adductor pollicis)
   • Elbow flexion test: elbow fully flexed, patient will complain of numbness and tingling in the ring and little fingers

Distinguishing between high and low ulnar nerve lesion

Causes of ulnar nerve palsies

1. Anatomical
   • Cubital tunnel syndrome (at the elbow - due to repeated elbow flexion leading to a traction injury)
2. Trauma
   • Anywhere along the course of the nerve
   • supracondylar fractures
   • Dislocation of the elbow
3. Degenerative arthritis
   • Compressing proliferative synovitis and osteophytes
4. Rare
   • Compression from tight fascia / ligaments
   • Tumour masses
   • Aneurysms
   • Vascular thromboses

Management of ulnar nerve palsies

1. Non-surgical
   • Avoid repetitive flexion-extension motions and prolonged elbow flexion
   • use of night splintage with elbow in extension
2. Surgical
   • Ulnar nerve decompression (decompression of root of cubital tunnel)
   • Ulnar nerve anterior transposition
   • Medial epicondylectomy