The swan neck deformity has three components: flexion of the metacarpophalangeal and distal interphalangeal joints and hyperextension of the proximal interphalangeal (PIP) joints. The deformity may develop as the result of synovitis in any of these joints and limits functional grasp. Clinical considerations * impaired grasp * synovitis/capsular laxity * intrinsic tightness Biomechanical considerations * volar plate weakening * dorsal displacement of lateral bands * PIP joint hyperextension * terminal extensor lag Reference: * Melvin JL. Rheumatic disease in the adult and child: occupational therapy and rehabilitation. 3rd ed. Philadelphia: F.A. Davis Company; 1989.