Its not physicaly possable to draw a sword from a scabbard on your back, especialy one as big as a two-handed sword (it can be done but you would need a a short or curved sword). What I want to know is why do we draw our swords from the right hip when it is quicker and needs less room to draw from the right hip assuming we are all right handed.
Huh? No it's not.
if you draw a sword from the right of your hip with your right hand you're more likely to acidentally stab yourself in the gut than draw your sword, with a dagger it might be true but you need some space with a sword, drawing from the left side gives you that, and is obviously faster.