In The Dark Knight Rises, when Bane is beating up Batman and then punches him repeatedly in the head, we see that Batman's head flattens on the side. Does this imply that Bane has actually crushed Batman's skull?
Nolan's Batman has a thick graphite cowl that acts as a helmet. It's not skin tight and actually protects his head. What you saw in that scene is Bane breaking that helmet. Bruce does sustain some head injuries, as seen in the clip below, but they seem like bruises and he does recuperate.