Radial nerve: anatomical course and lesions

This issue has not come up in an exam, as yet (at least not since 2000).

However, it may well appear one day. Radial nerve injury is a common complication of major traumatic humeral fracture.

Course of the radial nerve

Lesions of the radial nerve

Lesion at the axilla

• Motor deficits:
  • Triceps weakness
  • Brachioradialis weakness
  • Extensor weakness of the wrist - "wrist drop"
• Sensory loss:
  • Lateral dorsum of the hand and wrist
  • Dorsum of the thumb
  • Proximal dorsum of fingers 2 and 3

Lesion at the spiral groove of humerus

• Motor deficits:
  • Triceps is spared!
  • Brachioradialis weakness
  • Extensor weakness of the wrist - "wrist drop"
• Sensory loss:
  • Lateral dorsum of the hand and wrist
  • Dorsum of the thumb
  • Proximal dorsum of fingers 2 and 3

Lesion at the radial tunnel (humeroradial joint)

• Motor deficits:
  • Extensor weakness of the wrist - "wrist drop" - may be mild
• Sensory loss:
  • Lateral dorsum of the hand and wrist
  • Dorsum of the thumb
  • Proximal dorsum of fingers 2 and 3