Context: in the last round of a match, a boxer realizes his opponent is just repeating the same combination over and over. I think 骨 in the following sentence has a metaphorical meaning, but I don't know how to interpret it:
支えるのはもう… 剥き出した骨のみ
I think the general meaning of the sentence should be:
The only thing that supports him... is now exposed.
Here you can see the whole page for more context. Thank you for your help!