The basis for communication in anatomy and physiology assumes

The basis for communication in anatomy and physiology assumes anatomical position.  

Anatomical position is the position in which a person stands straight with his spinal cord stretched and straight, his chin remaining perpendicular with the body axis, and his feet joint side by side and his palms facing anteriorly.

This is the position which is used as the default position to explain the location and relationship of any organ or object inside body with surrounding organs. In anatomy and physiology both, anatomical position is the default position to explain the location of other organs. Thus, as any location is stated in these subjects, the position is taken to be anatomical position.  

the scientific method.