Certified Hand Therapist (CHT) Practice Exam

Which of the following characteristics is true about the central slip avulsion injury?

1. It usually affects the thumb

2. It is commonly associated with PIP joint injuries

3. It occurs only in multiple trauma cases

4. It primarily impacts the wrist joint

The correct answer is: It is commonly associated with PIP joint injuries

The central slip avulsion injury is a specific type of injury that involves the extensor tendon at the proximal interphalangeal (PIP) joint. This injury occurs when the central slip, a part of the extensor mechanism, is detached from its insertion on the dorsal surface of the middle phalanx. This injury is significant because it typically leads to an inability to extend the PIP joint, resulting in what is commonly referred to as a "buttonhole" or "lag" deformity. The fact that this injury is associated with PIP joint injuries indicates its importance in understanding how trauma to the finger affects its function. While the injury can occur in various contexts, it is most frequently noted in injuries that involve the PIP joint rather than in the thumb or wrist. The specific anatomy and function of the PIP joint and its extensor mechanism mean that this type of injury often requires targeted therapy and rehabilitation to restore proper extension and functionality to the finger. Understanding the specifics of central slip avulsion injuries is essential for effective diagnosis and treatment in hand therapy, reinforcing the importance of recognizing its typical association with PIP joint injuries.