What structure completely encases the synovial joint and attaches to the periosteum of the bones forming the joint?

• A. Synovial membrane
• B. Joint capsule
• C. Hyaline cartilage
• D. Tendon

Answer: (B)

The joint capsule. It forms a fibrous sleeve that completely encloses the synovial joint and anchors to the periosteum of the adjacent bones, creating the closed space of the joint. Inside, the inner synovial membrane lines the capsule and produces synovial fluid, while the outer fibrous layer provides stability. Hyaline cartilage covers the articular surfaces rather than encasing the joint, and a tendon attaches muscle to bone rather than surrounding the joint space.