Which of the following is a type of synovial joint?

• A. Cartilaginous joint
• B. Ball and socket
• C. Fibrous joint
• D. Hinge joint

Answer: (B)

Synovial joints are the freely movable joints that have a joint capsule, synovial cavity with fluid, and articular cartilage to reduce friction. A ball-and-socket joint fits this pattern: a rounded head of one bone sits into a cup-shaped socket of the other, all enclosed by a capsule and filled with synovial fluid. This design allows movement in many directions—flexion and extension, abduction and adduction, and rotation—giving the greatest range of motion seen in the body, as in the shoulder and hip. That broad, multi-directional movement is the key feature that makes ball-and-socket stand out as a typical example of a synovial joint. In contrast, cartilaginous and fibrous joints are connected by cartilage or fibrous tissue and lack a synovial cavity, so they aren’t synovial joints. Hinge joints, while also synovial, restrict movement to one plane, which is less characteristic of the defining flexibility demonstrated by ball-and-socket joints.