Final answer:
The true statement about a synovial joint is that synovial fluid lubricates the joint and prevents excessive wear on the joints. Bursae do not produce synovial fluid, and ligaments (not bursae) help stabilize synovial joints.
Step-by-step explanation:
Among the statements provided, the one that is true of a synovial joint is: Synovial fluid lubricates the joint and prevents excessive wear on the joints. Synovial fluid serves to reduce friction between the articulating bones, facilitating smoother and greater movements.
The joint cavity space in a synovial joint can change due to trauma or other factors, so statement B is incorrect. Bursae are fluid-filled sacs that help reduce friction and cushion pressure points between your bones and the tendons, muscles, and skin near your joints, but they do not produce synovial fluid, so statement C is incorrect. The synovial joint is stabilized by ligaments rather than bursae, making statement D incorrect.
Structural Features of Synovial Joints
Synovial joints, such as the knees, elbows, and shoulders, have a characteristic joint cavity filled with synovial fluid and are surrounded by an articular capsule. The capsule and supporting ligaments provide stability, while the articular cartilage and synovial fluid lubricate and cushion the joint, respectively.