In trigger finger (stenosing tenovaginitis), the anatomical site of pathological thickening causing triggering is:
- A A1 pulley at the level of the metacarpal head ✓
- B A2 pulley at the proximal phalanx
- C Flexor digitorum superficialis chiasm (Camper's chiasm)
- D Carpal tunnel at the wrist
Correct answer: A. A1 pulley at the level of the metacarpal head
Explanation
Trigger finger results from a size mismatch between the flexor tendon (FDS+FDP) and the A1 pulley, which overlies the metacarpophalangeal joint at the level of the metacarpal head. Fibrocartilaginous metaplasia of the A1 pulley causes constriction of the tendon sheath, producing the 'snapping' phenomenon. Treatment is local steroid injection or surgical release of the A1 pulley. The A2 pulley (B) is biomechanically critical and should not be divided.
Reference: Maheshwari Essential Orthopaedics, 6th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.