A young man punches a wall and presents with swelling and tenderness over the dorsal aspect of the hand just proximal to the little knuckle. X-ray shows a metacarpal neck fracture with apex-dorsal angulation. The typical deformity and the structure at risk from the sharp volar spike are:

• A Apex-volar deformity; digital nerves of the index finger
• B Apex-dorsal deformity with volar spike threatening the flexor tendons and digital vessels ✓
• C Apex-dorsal deformity; skin and extensor tendons dorsally
• D No characteristic deformity; risk limited to the metacarpophalangeal capsule

Explanation

A boxer's fracture involves the neck of the fifth metacarpal. The pull of the interossei flexes the metacarpophalangeal joint and the head tilts palmarward, producing the characteristic apex-dorsal angulation. The sharp dorsal cortex of the proximal fragment projects into the palm, where it endangers the flexor tendons and the digital neurovascular bundle. Moderate angulation of the fifth metacarpal neck is accepted because remodelling is excellent, but excessive angulation needs closed reduction.

Reference: Green's Operative Hand Surgery, 7th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.