Why is it important to use a system of location similar to north/south and east/west to describe location on a patient’s body?
I would assume that it would have to do with keeping it less confusing.
If someone were to say the left (fill in), then it could either mean their (patient's) or your (doctor's) left. Saying the west (fill in) would most instinctively mean the way you (doctor) perceive the cardinal directions. I really haven't the slightest idea, but that makes sense to me somehow.