Final answer:
The sagittal plane divides the body into right and left sides, with movements in this plane such as flexion and extension occurring around the medial-lateral axis.
Step-by-step explanation:
The sagittal plane, which separates the body into the right and left sides, is used primarily for flexion and extension movements. The medial-lateral axis, an imaginary line that extends from the medial (middle) to the lateral (side) parts of the body, is the center of rotation for these motions. For example, when someone flexes their knee or elbow, they are moving around the medial-lateral axis in the sagittal plane. It is referred to as a parasagittal plane, or less frequently, a longitudinal section, if it splits the body into unequal right and left sides.