Why aliens have digitigrade legs?even aliens from Andromeda.(edit)

Their legs feature the same anatomy as ours, with slightly different structure. This stance is called digitigrade, which will be addressed momentarily. I'm going to use a quarian for this exercise, but you can use any creature you wish, real or imagined, as long as it has a digitigrade posture.

Look at a quarian in profile. Let's start at the ground. Look at their toes. BioWare isn't entirely consistent in illustrating this well, but they are standing and walking on their toes. (I know it doesn't particularly look that way, but trust me. BioWare took artistic liberties.) This is what digitigrade means, that a species stands and walks on its toes. Humans, by contrast, are plantigrade, using the entire foot for standing and walking. The entire leg is built differently, as a result.

Follow the quarian's bones upward from the toes. Where your ankle and lower legs would be, that's their (very elongated) foot bones. That first major joint we arrive at is the ankle. Next come the (very short) lower leg bones, followed by another major joint, the knee. Notice it is not backward. From here, the upper leg is pretty similar to a human.

These digitigrade species do not have backward legs, knees or whatever. Their bones are proportioned differently, and their joints are positioned differently, but nothing is backward. I went through all of this, not to be pedantic, but because I suspect that many truly have no idea what is going on with these legs. I hope this was interesting, rather than obnoxious.