A young man who habitually wears a heavy watch strap develops tingling and numbness over the dorsum of the thumb, index and middle fingers and the corresponding dorsum of the hand. Grip strength and all movements are normal. Which nerve is involved?

• A Posterior interosseous nerve
• B Superficial branch of the radial nerve ✓
• C Lateral cutaneous nerve of the forearm
• D Palmar cutaneous branch of the median nerve

Explanation

Compression of the superficial radial nerve, sometimes called Wartenberg's cheiralgia paraesthetica, is classically caused by tight watchbands or handcuffs. This branch is purely sensory, supplying the dorsolateral hand and dorsal surfaces of the lateral three and a half digits up to the nail beds, so there is no motor deficit. The posterior interosseous nerve is motor to the extensors, and the lateral cutaneous nerve of the forearm supplies the lateral forearm rather than the hand.

Reference: Snell's Clinical Anatomy by Regions, 10th ed.

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Written and medically reviewed by the StethoPrep medical team.