Citation:
In the context of anatomy and physiology, retraction is a movement that pulls a part of the body backward or towards its posterior position on the sagittal plane. It is commonly observed in movements like pulling the shoulders back.
This is the opposite movement of retraction, involving pushing a part of the body forward or away from its posterior position.
Extension refers to increasing the angle between two bones at a joint, essentially straightening or opening up a joint.
Flexion is the act of decreasing the angle between two bones at a joint, typically bending or folding a joint