Final answer:
Medial rotation is the term used to describe the relative motion or twist between the long bone in the leg's shaft and neck, where the bone rotates toward the midline of the body. Conversely, lateral rotation refers to the movement of the bone as it rotates away from the midline of the body.
Step-by-step explanation:
Rotational movement between the long bone in the leg's shaft and neck is referred to as medial rotation. This is the movement of a bone as it rotates toward the midline of the body. In contrast, lateral rotation is the term used to describe the movement of a bone as it rotates away from the midline of the body.