What common result occurs when the PIP joint is subjected to a hyperextension force?

• A. Boutonnière deformity
• B. Trigger finger
• C. Swan neck deformity
• D. Jersey finger

Answer: (C)

The correct choice, which identifies the common result of hyperextension at the PIP (proximal interphalangeal) joint, is the swan neck deformity. This condition typically arises when a hyperextension force causes a stretch of the volar plate and a disruption of the collateral ligaments of the joint.

In swan neck deformity, the result is a characteristic posture of the finger where the PIP joint is hyperextended while the distal interphalangeal (DIP) joint is flexed. The involuntary positioning occurs due to an imbalance of muscle forces and structures supporting the finger, often seen in conditions like rheumatoid arthritis.

Understanding the mechanics of this injury is crucial, as it highlights how specific forces can lead to predictable patterns of deformity, which is essential in both diagnosis and rehabilitation in athletic training contexts. This awareness can guide appropriate interventions to restore function and mobility to the afflicted digits.