Radial Nerve Lesions
Approach
- Expose elbows
- Ask patient to place hands palm upwards on a pillow
- Observe wrist drop
- Inspect
- Unlikely to be wasting of hand muscles
- Wrist drop
- If high radial elsion - whole arm deformed in Erb's palsy
- 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
- 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
- High
- Brachial plexus - saturday night palsy
- Middle
- In spiral groove of humerus - # middle 1/3 f humerus, sometimes secondary to tourniquet use
- Low
- Elbow - due to local wounds, surgery, fracture
