What is the term for lying face down?

The term for lying face down is "prone." This position is commonly used in various medical examinations and procedures, as well as during certain types of therapy and rehabilitation. Being in a prone position can affect the physiological responses of the body, such as respiratory function and circulation, which is why it might be relevant in medical contexts. Understanding the term "prone" is crucial for healthcare professionals, including medical assistants, as they frequently assist in positioning patients for exams or treatments.

The other terms in the question refer to different positions: "supine" means lying face up, "Trendelenburg" refers to lying on the back with the legs elevated above the head, and "sitting" describes an upright position. Each of these has its specific applications in healthcare, but they do not describe the position of lying face down.