Final answer:
A patient lying face down is in the prone position, which is used to indicate a face-down orientation in medical contexts.
Step-by-step explanation:
A patient who is found lying face down is said to be in a prone position. When talking about body orientations, 'prone' describes a face-down orientation, whereas 'supine' refers to a face-up orientation. These terms are often employed in medical settings to describe how a patient is positioned during physical examinations or surgical procedures. The correct option to describe a patient lying face down is a. The person is prone with upper limbs, including palms, touching sides and lower limbs touching at sides.