Regarding up/down vs left/right. Perspective is an issue with left/right, but generally not for up/down. Everyone in the vast majority of circumstances share th

Regarding up/down vs left/right. Perspective is an issue with left/right, but generally not for up/down. Everyone in the vast majority of circumstances share the same up/down perspective. When it comes to left/right, you often have to do some mental acrobatics to figure out what the frame of reference is, in order to figure out which way is left or right from that frame of reference. It's easy to just point and say "that way", but to know whether to say "left" or "right" you have to think, "ok, this is my left, but which way is he facing, is that his right? ok, but if I say right, will he think I'm saying his right or mine?" That's why sailors invented port and starboard. Maybe we should apply this to doctors. "Ok, we're operating on the starboard knee today!" To be fair, I assume they use left/right from the perspective of the patient, but I could see using a separate pair of terms being useful, the same way it's useful to say port/starboard instead of saying left/right and an understanding that the perspective is focused toward the bow (front) of the ship.