What term describes the act of increasing the angle between two parts, effectively straightening a limb?

The term that describes the act of increasing the angle between two parts, effectively straightening a limb, is extension. In anatomical terms, extension refers to the straightening of a joint or the straightening of a limb after it has been bent, which increases the angle between the body parts involved. For example, when you straighten your arm at the elbow, you are extending that joint.

Understanding this term is crucial in health sciences as it helps in comprehending movements that occur in physical therapy, rehabilitation, and anatomy. This terminology is used extensively when discussing range of motion, joint mobility, and physical fitness.