What type of joint contains a joint cavity?

• A. Synovial
• B. Fibrous
• C. Cartilaginous
• D. Hinge

Answer: (A)

The key idea is that only certain joints have a fluid-filled space called a joint cavity. This cavity is a hallmark of synovial joints. In these joints, the ends of the bones are covered with articular cartilage and enclosed by an articular capsule that contains synovial fluid produced by the synovial membrane. This setup creates a lubricated, mobile space where movement occurs with minimal friction, which is why synovial joints are described as diarthroses with a cavity.

Fibrous joints connect bones with dense connective tissue and lack a joint cavity, so they allow little to no movement. Cartilaginous joints connect bones via cartilage and likewise do not have a fluid-filled cavity, resulting in more limited movement. A hinge joint is a specific type of synovial joint (such as the elbow or knee) that has a cavity as well, but it’s a particular example within the broader synovial category.