A 22-year-old boxer strikes an opponent with a closed fist and injures his hand. X-ray shows a metacarpal neck fracture with dorsal angulation of the distal fragment. Which metacarpal is characteristically involved, and what degree of palmar (apex dorsal) angulation is generally considered acceptable without reduction?

• A Second metacarpal, up to 5 degrees
• B Third metacarpal, up to 20 degrees
• C Fifth metacarpal, up to about 40 degrees ✓
• D Fourth metacarpal, up to 40 degrees

Explanation

The boxer's fracture is a fracture of the neck of the fifth metacarpal following axial loading through a clenched fist. Because the fourth and fifth carpometacarpal joints are mobile and allow compensatory flexion, apex-dorsal angulation up to approximately 40 degrees at the fifth metacarpal neck is accepted without reduction. The index and middle metacarpals are rigidly fixed to the carpus and tolerate far less angulation.

Reference: Apley's System of Orthopaedics and Fractures, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.