Which deformity features extension at the PIP joint and flexion at the DIP joint?

• A. Boutenniere Deformity
• B. Swan-neck Deformity
• C. Raynaud's Phenomenon
• D. Trigger Finger

Answer: (B)

The swan-neck deformity is characterized by a specific pattern of joint movements: extension at the proximal interphalangeal (PIP) joint coupled with flexion at the distal interphalangeal (DIP) joint. This occurs due to an imbalance in the surrounding muscles and tendons, often resulting from conditions like rheumatoid arthritis. The proximal phalanx is angled backward, while the terminal phalanx is bent forward, resembling the neck of a swan.

Understanding this mechanism is essential for occupational therapy practice as it informs appropriate interventions aimed at alleviating symptoms and improving function for individuals with this deformity. In contrast, other conditions mentioned, such as Boutonniere deformity, feature the opposite joint positions, wherein the PIP joint is flexed and the DIP joint is extended. Raynaud's phenomenon is a vascular condition impacting blood flow rather than joint positions, and trigger finger involves a different mechanism associated with tendon dysfunction. All these clarifications help solidify the understanding of joint deformities and their implications in practice.