It is without any doubt or confusion that, at least as is portrayed in the movie, that Paul broke all the bones in his right hand going down fighting. That is the *entire* point of the conversation between Norman and his father. Perhaps the book says something else but I am going by only what is on screen in the movie.
shareTake it easy fella. Go have a sandwich or something.
shareI don't think it's that clear cut in the movie. It could be other things too, such as torture because of the debt he owed and didn't pay back or punishment because he was caught cheating. Breaking hands has always been an efficient way for casino owners to punish the cheater and destroy his skill set at the same time.
Also, i doubt that one can break "nearly all bones in his hand" merely by fighting. After one or two bones are broken, the hand is not of much use anymore, which should prevent further damaging and from then on he would also have broken bones in the other hand too because that's the one he would have to use to defend himself.
If most bones were broken, it's in all likeliness because the hand has been crushed, which points towards him having been tortured/beaten up by several guys.
In order of likeliness, i would put your hypothesis in second place:
1) Tortured
2) Fighting
3) Cheating
People who don't like their beliefs being laughed at shouldn't have such funny beliefsī²