It does not change; the directional terms are given in relation to the anatomical position, not the patient position.
lying flat, face down
The medical term for a patient lying on his belly is the prone position. The opposite of the prone position is supine, or the patient lying flat on his back.
Transverse means acting, lying, or being across: set crosswise
The dorsum is medical terminology for the back. Hence, the dorsal position is lying on your back.
prone means "face down", example lying face down on your stomach. Supine being the opposite.
Prone
prone
The procedure is performed with the patient lying on her back with her legs in stirrups.
Orthopnea is the medical term meaning shortness of breath when lying flat.
The procedure is performed with the patient lying on her back with her legs in stirrups.
Prone means lying horizontal with the face down. Pronation is the action of lying prone.
Aside from the Latin, the most common term for lying on your back is supine.