It was pretty common up till the 60s and maybe later to get human skeletons form South Asia, they were often obtained from flood or landslide victims, and have no identifiers except maybe an inventory number.

Modern stuff however, is obtained when someone donates their remains, and is often only held for a limited time before interred. They are anonymized to the student / researcher, but there is a record of who they were. The med school's anatomy lab here has some pretty neat stuff (or did 20 years ago when I went), including a woman's plasticized torso that had been sliced into 1 inch wafers, and an autopsied man who was born with his organs rotated in his body so that everything was on the wrong side. I still have the illustrations I drew from that anatomy class somewhere.

It may have been a donation. Donating your body to science can result in you becoming a classroom skeleton, or blown up in the sky with a rocket. If you're lucky enough, they put you in a field and let your body rot, while observing the process. You don't really get a say in it, but cadavers are used for all sorts of things.