The bones of the head also give rise to the bony component of the nasal skeleton. The bones of the head create the bony orbits: symmetrical cavities which surround and protect the eye and associated structures. The temporal bone, located laterally, supports the temporal lobes, as well as containing the middle and inner parts of the ear. Fibres from the olfactory nerve (CN1) pass through the ethmoid bone into the nasal cavity allowing the sense of smell. The ethmoid bone forms the roof of the nasal cavity. The sphenoid bone contains the sphenoid sinuses. The number of hollow bones varies among species, though large gliding and soaring birds tend to have the most. The sphenoid bone is a butterfly-shaped bone consisting of a body, and upper and lower wings. The mandible forms the lower jaw and is the site of insertion for the lower teeth. The mandible is the strongest and largest bone of the face. The bones of the cranial base allow articulation with the first cervical vertebrae, as well as with the mandible to form the temporomandibular joint. The calvarium is comprised of the frontal, occipital and two parietal bones, and the cranial base is comprised of the frontal, sphenoid, ethmoid, occipital, parietal and temporal bones. The skull of a snake is a very complex structure, with numerous joints to allow the snake to swallow prey far larger than its head. The cranium can be divided further in to the calvarium and the cranial base.
Neurovascular structures enter and leave the cranium through the cranial foramina. The cranium encloses and protects the brain whereas, the bones of the facial skeleton provides support to facial soft tissues. The 22 bones of the skull can be divided in to two main categories: the cranium and the facial skeleton. They are a type of fibrous joint, which are immovable. Of those 22 bones, 8 of them are cranial bones, or bones that serve as protection of the brain, and 14 of them are facial. The bones of the head meet at joint lines called sutures. The bones of the head form a protective cavity around the brain.
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