Which statement accurately describes joints and their roles?

• A. The elbow is a hinge joint that allows rotation.
• B. The ball-and-socket joint in the shoulder allows only one plane of movement.
• C. Hinge joints such as the knee allow flexion and extension; ball-and-socket joints like the hip allow multi-directional movement.
• D. The skull is a ball-and-socket joint.

Answer: (C)

Joints determine how the bones can move. Hinge joints allow movement in one plane, mainly bending and straightening (flexion and extension). The knee is the classic example, where the leg bends at the knee and straightens to push off or stand.

Ball-and-socket joints, on the other hand, permit movement in multiple directions, including up and down, side to side, and rotation. The hip is a ball-and-socket joint, giving a wide range of motion in various directions.

The skull isn’t a ball-and-socket joint; the joints in the skull are sutures that stay fairly fixed once adult, not designed for the broad movements of a ball-and-socket joint.

So the statement that matches reality is that hinge joints like the knee allow flexion and extension, while ball-and-socket joints like the hip allow multi-directional movement.