Which feature describes a synovial joint?

• A. Bones joined by dense fibrous tissue with no joint cavity.
• B. Contains a fluid-filled joint cavity and synovial membrane.
• C. Made of fibrocartilage with limited movement.
• D. Bones fused by bone tissue.

Answer: (B)

Synovial joints are defined by having a joint cavity that is fluid-filled and lined by a synovial membrane. This membrane and the surrounding capsule produce and contain synovial fluid, which lubricates the joint and reduces friction as bones move. The ends of the bones are covered with articular cartilage, and the joint is stabilized by a fibrous capsule and ligaments, all of which together allow a wide range of movement.

Other joint types lack this cavity. Joints held together by dense fibrous tissue have no joint cavity and tend to be immovable or only slightly movable. Joints linked by fibrocartilage have limited movement and also lack a true cavity. When bones are fused by bone tissue, there is no movable joint at all.