Following a humeral shaft fracture, a patient develops wrist drop and loss of finger extension. Sensation is intact over the dorsum of the hand. The nerve injured and its expected prognosis by Sunderland classification are:

• A Radial nerve — Sunderland Grade III (axonotmesis with endoneural disruption); partial recovery in 3–6 months
• B Radial nerve — Sunderland Grade I (neuropraxia); full recovery expected in 6–12 weeks ✓
• C Posterior interosseous nerve — Sunderland Grade V (neurotmesis); surgical repair required
• D Median nerve — Sunderland Grade I; full recovery expected

Explanation

Radial nerve palsy from a closed humeral shaft fracture (Holstein–Lewis fracture at the junction of middle and distal thirds) is most commonly a neuropraxia (Sunderland Grade I — conduction block without axonal disruption), due to traction or contusion. Sunderland Grade I injuries recover fully within 6–12 weeks. Exploration is indicated if no clinical or EMG recovery is seen by 3 months. Sensory preservation over the dorsum of the hand (posterior cutaneous nerve of forearm branch, given off proximal to the fracture) further supports partial neuropraxia.

Reference: Maheshwari Essential Orthopaedics, 6th ed.

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Written and medically reviewed by the StethoPrep medical team.