What term describes a body part moving backward?

The term that describes a body part moving backward is retraction. This motion specifically refers to the movement of a body part towards the posterior (back) side of the body. For instance, when the shoulder blades are drawn together or when the jaw is brought back into its resting position, it is referred to as retraction.

In contrast, other terms have distinct meanings. Extension is the straightening of a joint resulting in an increase in the angle between two bones, such as straightening the elbow when extending the arm. Flexion is the opposite, involving bending a joint, thus decreasing the angle, as seen when bending the arm at the elbow. Protraction describes movement forward, where a body part is pushed out or away from the midline, such as reaching the jaw forward. Understanding these definitions helps clarify the specific actions associated with each term in anatomical movements.