medialtolateral

Medialtolateral, commonly written mediolateral, is an anatomical directional term used to describe orientation or movement that runs from the midline of the body toward the outer side. It denotes a plane, axis, incision direction, or component of motion that progresses from medial to lateral.

The term is applied across disciplines such as anatomy, radiology, surgery, and biomechanics. In imaging, a mediolateral projection or view refers to an examination where the imaging beam or orientation passes from the medial side toward the lateral side, as in a mediolateral knee radiograph. In surgical contexts, a mediolateral approach or incision begins on the medial aspect and extends toward the lateral aspect of the region of interest.

In biomechanics and kinesiology, movements can be described as mediolateral when the motion occurs in or about the mediolateral axis—the axis that runs from the midline of the body to the side—important for flexion-extension of joints like the knee or hip, which occurs around a mediolateral axis. The term also appears in descriptions of lateral displacement or alignment of structures viewed from a medial-to-lateral perspective.

Etymology: mediolateral derives from Latin medialis (midline) and lateralis (lateral), and is commonly hyphenated as mediolateral or written as medial-to-lateral. While the term is concise, its exact meaning can depend on context, so it is often specified alongside the plane, axis, or procedure being described.