That happened to a baseball player a few years back. He was walking down a city street with a teammate and one of those store signs was hanging above the sidewalk and he jumped up to slap it when his ring caught on the sign’s metal frame and it stripped the meat right off his finger bone.
It’s called ‘degloving’. I don’t recall whatever happend to him, but I assume that the flesh could be put back on if done quickly and stiched..................
Apparently some cases of ring avulsion (degloving) can be surgically repaired, depending on severity and promptness of treatment. In Rod’s case, they just amputated what was left of the finger, pretty much only the bone.