What type of joint is the knee?

The knee is classified as a hinge joint, which is primarily designed to allow movement in a single plane, specifically flexion and extension. This type of joint operates similarly to the way a door opens and closes, permitting a back-and-forth motion. The structure of the knee joint features a complex arrangement of bones, ligaments, and cartilage that allows it to function effectively as a hinge, while still providing stability and support to the body during various activities like walking, running, and jumping.

In contrast to hinge joints, ball-and-socket joints allow for a greater range of motion, including rotation, which does not characterize the knee. Pivot joints facilitate rotational movement around a single axis, while gliding joints enable limited movement over a flat surface. The specific functions and anatomical configurations of these joint types differentiate the knee's primary action as that of a hinge joint.