Radial nerve injury commonly presents with which sign?

Radial nerve injury commonly presents with which sign?

• A. Weakness of wrist flexors
• B. Numbness in the medial forearm
• C. Weakness of finger flexors
• D. Wrist drop

Answer: (D)

Radial nerve injury cripples the extensor muscles of the forearm, so the wrist cannot be actively extended. This motor deficit produces the classic wrist drop, where the hand rests in a flexed position because the flexors dominate. Sensory loss, when present, is typically on the dorsolateral hand and dorsum of the forearm, not the medial forearm. The other signs would involve different nerves: wrist or finger flexion weakness points to median or ulnar nerves, and medial forearm numbness comes from medial cutaneous nerves rather than the radial nerve.

Radial nerve injury cripples the extensor muscles of the forearm, so the wrist cannot be actively extended. This motor deficit produces the classic wrist drop, where the hand rests in a flexed position because the flexors dominate. Sensory loss, when present, is typically on the dorsolateral hand and dorsum of the forearm, not the medial forearm. The other signs would involve different nerves: wrist or finger flexion weakness points to median or ulnar nerves, and medial forearm numbness comes from medial cutaneous nerves rather than the radial nerve.