Translation:I lose a nail from my right hand.
It seems to be a question and consequently a choice between belonging and origin. If you believe belongs to the person when was still on the hand "of" is the correct preposition. On the contrary if it is believed that the nail that is no longer on the end came from the person's hand "from" is correct. Further more "de" can be translated as : of, from, by,in, at, on, about,as, with, for. So in conclusion both should be accepted.Some languages like Italian don't even need a proposition : mi e caduta un'unghia, se me caio la una( sorry for the lack of accents)