Which of the following joints is classified as a hinge joint?

A hinge joint is characterized by its ability to allow movement in one plane, effectively functioning like the hinge on a door. It permits flexion and extension, which is the bending and straightening movement, similar to how a door opens and closes.

The elbow is the prime example of a hinge joint in the human body. Its structure allows the forearm to move toward and away from the upper arm, enabling actions such as lifting and lowering objects.

In contrast, the shoulder and hip joints are classified as ball-and-socket joints, which allow for a wider range of motion, permitting rotational movement as well as movements in multiple planes. The wrist, while it does allow for some flexion and extension, is more accurately classified as a complex joint with multiple types of movement available due to its structure and composition. Therefore, the elbow stands out as the specific hinge joint among the options provided.