They can either protect our internal organs and our tissues and they can also serve as attachment points for muscles because of their high surface area. So they contain compact bone on the surface and in the middle, at the center, they contain spongy bone. So what are some examples of flat bones? So the skull, the cranium, is an example of flat bones. So we have many of these flat bones that essentially fuse together as the organism becomes an adult, as the organism grows. And the skull.