Shoulder and hip joints are examples of which type of joint?

• A. Hinge joints
• B. Pivot joints
• C. Ball-and-socket joints
• D. Gliding joints

Answer: (C)

Ball-and-socket joints allow movement in many directions because a rounded head fits into a cup-like socket, creating a wide range of motion. In the shoulder, the humeral head sits in the shallow glenoid cavity of the scapula, and although the socket isn’t very deep, the joint is enabled and stabilized by surrounding muscles and ligaments, giving extensive mobility. In the hip, the femoral head fits into the deeper acetabulum, providing a strong balance of stability and flexibility for weight-bearing activities. This setup lets the joint move in flexion and extension, abduction and adduction, rotation, and circumduction. Other joints are more limited in direction: hinge joints move mainly in one plane, pivot joints rotate around a single axis, and gliding joints allow small sliding movements between surfaces.