The skull, also known as the cranium, is the bone that protects the brain. It is a bony structure that surrounds and encloses the brain, providing it with physical protection from external forces that could cause damage. The skull is composed of several bones that are fused together, including the frontal, parietal, temporal, occipital, sphenoid, and ethmoid bones. The skull also contains several openings and cavities, such as the orbits for the eyes, the nasal cavity, and the ear canals.