Radial nerve - lesions at spiral groove level

Causes

• Humerus fracture.
• Compression injury during sleep (Saturday night palsy) or turniquet application.
• Entrapment by musculotendineous arch of lateral head of triceps muscle.
• Progressive, severe, painless radial neuropathy may present as a complication of chronic intramuscular injection.

Symptoms & signs

Similar to lesions at the axillary level with some important differences:

• Triceps muscle is spared.
• Sensibility in dorsal arm is unaffected.
• Sensibility in the dorsal forearm may be unaffected.