carbon-fibre bones and med-technology

[Ashen Key]

Couple of questions that I was interested in hearing you guys' thoughts on (both came up during research for a fic).

How would Na'vi bones act under physical stress?

Or rather, how would their carbon-fibre reinforced bones break or fracture? I read somewhere that they might splinter more then break, but carbon itself (so my research has lead me to believe) does break when under a sharp enough shock (like, say, a hammer). And also, carbon doesn't bend under pressure, it just snaps, so it seems to lose flexibility with the strength....but then again, we're taking about a composite of bone with carbon, so....Yeah. I'm not sure how Na'vi bones would actually react under physical stress, or what would cause them to break. (For fic, I need to break something to cause a character to have a limp, just not sure on the details yet).

What level of medicine-technology do you think the Na'vi have?

I'm assuming that as far as helpful herbs and drugs are concerned, the Na'vi are set, but I'm not sure on their level of tech as far as surgery/setting bones/physical therapy/etc would be. Any theories?