> I'm not sure why you'd classify everything up to destroying the skin as 1-3 and then label 4 as destroying bone.
I'd wager that from a medical standpoint there is no functional difference between burning through fat layer, or going even deeper and hitting muscle and/or bone.
Isn't 4th degree the last stop?
https://www.urmc.rochester.edu/encyclopedia/content.aspx?Con...
After burning through muscle and bone, there is not much beyond that to warrant another level in the classification.
In fact, some classifications just end in 3rd degree, and bundle muscle and bone damage in it.