Which term is used to describe the act of increasing the angle of a joint?

The term that describes the act of increasing the angle of a joint is indeed extension. In anatomical terms, extension is the movement that straightens a joint, thereby increasing the distance between the body parts involved. For example, when you straighten your arm at the elbow, you are extending the joint, as you are increasing the angle between the forearm and the upper arm.

In anatomy, flexion refers to decreasing the angle at a joint, such as bending the elbow. Elevation typically describes moving a body part superiorly, such as shrugging the shoulders, while rotation involves turning a body part around its axis, such as twisting the neck or torso. Understanding these definitions helps clarify joint movements and is crucial for comprehending human anatomy and physiology.