trivet is right: cadaver is the (mainly) medical term for corpse. Both words have Latin origins, so that's clearly not the reason for the doctors choosing "cadaver" over the other. Cadaver comes from cadere to fall, while corpse comes from corpus meaning body.
So perhaps the doctors want to make it clear that the body is not merely a body but a fallen (dead) one before they start hacking it about???
I have never heard cadaver used in reference to anything but human remains, but I have occasionally seen the word corpses used to refer to non-humans (though always it's used as an adjective). Anyone else notice this?
I mean one never says, when speaking of squirrels for example, "corpses," unless one says "squirrel corpses." I said that wrong. I meant the animal in question is the adjective. Brain fuzzy. Need sleep.
I've always thought cadaver is such a lovely word to have such a ... non-lovely... meaning. Innit? Corpse is not such a nice word, though I like copse, precisely because it doesn't sound like such a nice thing, but it is.
I have an osteochondral lesion and a brevis tear in my right ankle. My orthopedic surgeon said that I'll probably need to replace a small area of my ankle with "cadaver bone". I was creeped out at first, but now I'm okay with the idea... as long as I'm assured that I won't be receiving "zombie bone".