American Board of Surgical Assistants (ABSA) Orthopedic Practice Test

What anatomical structure acts as a gliding mechanism by containing synovial fluid?

1. A tendon

2. A ligament

3. A bursa

4. A capsule

The correct answer is: A bursa

The correct answer is that a bursa acts as a gliding mechanism by containing synovial fluid. A bursa is a small, fluid-filled sac located in areas where there is friction, such as between muscles, tendons, and bones. The synovial fluid found inside a bursa reduces friction and allows for smooth movement during activities that involve joint motion. This function is essential in preventing wear and tear on the surrounding tissues, thereby improving overall joint function and comfort. In contrast, tendons primarily attach muscles to bones and facilitate movement, while ligaments connect bones to other bones and provide stability to joints; neither of these structures is specifically designed to reduce friction through synovial fluid. A joint capsule, while it does contain synovial fluid, serves primarily as a protective enclosure for the joint rather than acting as a lubricating structure like a bursa does.