During WW2 Nazi experimentation on humans took place, and there were similar practices taking place in Japan as well. Did any of these horrific and inhumane research methods actually result in any new findings with regards to human anatomy, medicine, etc.?
No. Not really. The nature of those "experiments" made it so that they were rather non-scientific and cared close to nothing for actual beneficial progress in medicine. See this answer and this one by /u/commiespaceinvader