What are the positions associated with the Swan neck deformity?

The Swan neck deformity is characterized by a specific positioning of the fingers, most often seen in conditions such as rheumatoid arthritis. In this deformity, the proximal interphalangeal (PIP) joint is hyperextended, while the distal interphalangeal (DIP) joint is flexed. This results in a distinctive appearance, where the finger resembles the neck of a swan, hence the name.

The hyperextension of the PIP joint is typically due to imbalances within the muscles and tendons surrounding the joints, leading to the inability to properly stabilize the PIP joint while the DIP joint flexes. This pattern can lead to functional limitations and is significant in the assessment of hand deformities and management in patients with arthritis or similar conditions. Understanding this specific deformity and its joint positions is crucial for both diagnosis and treatment planning.