The skull is that bony protective layer that wraps the whole brain up. It gets around about 15%, 15 to 20% of the blood that leaves the heart every minute. These connective tissue layers actually help protect it from things that are floating through the bloodstream. And so, which are probably more dangerous than... well, I wouldn't say more dangerous, but probably you're more likely to be exposed to some sort of toxin in the environment than some sort of physical trauma.