A competitive rock climber reports a sudden pop in the middle finger during a crimp grip. He now has palmar displacement of the flexor tendons during resisted finger flexion, visible as bowstringing across the proximal phalanx. Which structure has been ruptured?

• A A1 pulley
• B Transverse metacarpal ligament
• C A4 pulley
• D A2 pulley ✓

Explanation

The A2 pulley, located over the proximal portion of the proximal phalanx, is the strongest and biomechanically the most important annular pulley. Rupture, classically in climbers using the crimp grip, allows the flexor tendons to bowstring away from the bone, increasing the moment arm and reducing efficiency of flexion. The A1 pulley is the site of trigger finger release, not climber injuries.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.