I had a hard time finding a good image of a Ball skull, so I found an Eastern Hognose. This is looking up from the belly of the snake (ventral view):

As you can see, there's little protection on the snake's head to prevent it from much brain trauma. Some protection covers it, and it varies from species to species ("hot" or venomous snakes having the most protection, I've found) but for the most part, snakes don't have much to keep their heads safe.