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

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

References

For a reference, I direct the time-rich reader to Sir Sydney Sunderland's "Nerves and Nerve Injuries", from 1968. (Not available as full text in Google, unfortunately.)

For brachial plexus injuries, I recommend Alain Gilbert's book.

For peripheral nerves, there is Haymaker, Webb, and Barnes Woodhall. Peripheral nerve injuries: principles of diagnosis. Thieme, 1998.

Vanderpool, D. W., et al. "Peripheral compression lesions of the ulnar nerve."Journal of Bone & Joint Surgery, British Volume 50.4 (1968): 792-803.