Every wind instrument which require the two hands to press keys (saxophone, clarinet, oboe…) have the left hand of the player being the top one. This consistency makes it easier to switch from one instrument to another but is there a particular reason for that?
One could think that both hands are equally used on these instruments but I remember, as a left-handed person, trying to grab the saxophone the other way around when I started (it did not last long). There are lefties guitar, while, even if both hands do not have the same role, both of them are pretty active. If there is a physiological reason for having the left hand on top, then why don't we have left-handed wind instruments?