The skull is the hard part of your head. It is a hollow, rigid structure made of bone, and is attached to the top of your spine. It protects your brain and eyes like a tortoise's shell protects its body.
The muscles you use for chewing, smiling, frowning, laughing and other facial expressions are attached to the skull.
The skull is divided into two parts: the "cranial" part or "cranium" (the top part which covers the brain) and the "facial" part (the bones at the front that shape the face).