Swan neck deformity after distal interphalangeal joint flexion contractures: a biomechanical analysis.

The relationship between the flexor and extensor systems of the digits is both intricate and balanced, such that disruption of one system can affect the entire dynamics of the finger. The imbalance may be obvious, whereas the precipitating factor may be less obvious. These authors describe a case and provide a detailed biomechanical analysis of how a flexion contracture of the distal interphalangeal joint led to a swan neck deformity in one of their patients.