A 48-year-old woman with long-standing rheumatoid arthritis has hyperextension of the proximal interphalangeal joint and flexion of the distal interphalangeal joint of the right index finger. This deformity is called:
- A Boutonniere deformity
- B Mallet finger
- C Swan neck deformity ✓
- D Trigger finger
Correct answer: C. Swan neck deformity
Explanation
Swan neck deformity in rheumatoid arthritis is characterised by hyperextension of the proximal interphalangeal joint with compensatory flexion of the distal interphalangeal joint. Boutonniere deformity is the opposite: flexion of the proximal interphalangeal joint and hyperextension of the distal interphalangeal joint. Mallet finger results from extensor tendon disruption at the distal interphalangeal joint. Trigger finger is a stenosing tenosynovitis of the flexor tendon.
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.