Sound is transmitted by ALL the bones in your body. You hear some sound through your tailbone, in fact. But by far, the most comes through your ear canals - which ought to be no surprise. The only way to muffle all bone transmission would be to encase yourself completely in foam. Of course, breathing would be an issue ...
Fortunately, bone transmission is pretty inefficient. It would take sound levels high enough to kill you outright to damage your hearing by bone transmission alone.
Good friend toad, that's not quite correct. Exit pressure of some magnum rifles exceeds 15Kpsi even with 30" barrels. That equates to 140+dB. A 16" barrel in many different chamberings from .223 up can top that easily.
