Which axis is described as running from the head toward the feet (top to bottom)?

• A. Longitudinal axis of rotation
• B. Frontal axis
• C. Anteroposterior axis
• D. Vertical axis

Answer: (A)

The axis described runs along the length of the body from head to toe. This is the longitudinal axis. It sits along the body's length, so movements that rotate around it occur in the transverse (horizontal) plane, producing twisting or rotational actions such as turning the trunk or twisting the hips. The other axes are oriented differently: a left–right axis runs across the body and supports rotations in the sagittal plane (like flexion and extension), while the front-to-back axis runs from the chest to the back and supports movements in the frontal plane (like abduction and adduction). In this top-to-bottom description, the longitudinal axis is the best match.