Approach

• Expose elbows
• Ask patient to place hands palm upwards on a pillow
• Observe wrist drop

1. Inspect
   • Unlikely to be wasting of hand muscles
   • Wrist drop
   • If high radial elsion - whole arm deformed in Erb's palsy
2. Sensory assessment
   • Loss of sensation over 1st dorsal interosseus (between thumb and index finger)
   • Also for sensory loss over the dorsal aspect of the forearm
3. Motor assessment
   • Begin with the Metacarpophalangeal joint extensors (extension lost)
   • Fix MCPJ - demonstrate extensio at the PIPJ (lumbricals and interossei are supplied by median and ulnar nerves)
   • Test triceps - demonstrate weakness in high radial nerve lesions

Causes of radial nerve lesions

1. High
   • Brachial plexus - saturday night palsy
2. Middle
   • In spiral groove of humerus - # middle 1/3 f humerus, sometimes secondary to tourniquet use
3. Low
   • Elbow - due to local wounds, surgery, fracture