Certified Hand Therapist (CHT) Practice Exam

What ligament helps prevent dorsal subluxation of the metacarpal base?

1. Transverse retinacular ligament

2. Oblique beak ligament

3. Triangular ligament

4. Collateral ligament

The correct answer is: Oblique beak ligament

The oblique beak ligament plays a critical role in preventing dorsal subluxation of the metacarpal base, particularly in the thumb. This ligament creates a stabilizing effect around the carpometacarpal joint, providing support during pinching and gripping activities. Its anatomical position and tension help to maintain the alignment of the metacarpal, thus preventing excessive movement that could lead to dorsal subluxation, which would compromise hand function. In contrast, the other ligaments listed have different functions and areas of focus. The transverse retinacular ligament primarily serves to stabilize the extensor tendons as they cross the proximal interphalangeal joint but does not directly influence the position of the metacarpal base. The triangular ligament, also not directly involved in stabilizing the metacarpal base, is related to the structure of the extensor tendons and their movement. Lastly, the collateral ligaments provide stability to the joints primarily in the frontal plane during finger motion but do not specifically prevent dorsal subluxation at the metacarpal base.