Skull: Cranium and Facial Bones
The skull consists of 8 cranial bones and 14 facial bones. The bones are listed in Table , but note that only six types of cranial bones and eight types of facial bones are listed because some of the bones (as indicated in the table) exist as pairs.
The bones of the skull provide protection for the brain and the organs of vision, taste, hearing, equilibrium, and smell. The bones also provide attachment for muscles that move the head and control facial expressions and chewing.
Figures 1 and 2 illustrate specific characteristics of these bones, while some general features of the skull follow:
- Sutures are immovable interlocking joints that join skull bones together.
- Fontanels are spaces between cranial bones that are filled with fibrous membranes. The spaces provide pliability for the skull when it passes through the birth canal and for brain growth during infancy. Bone growth eventually fills the spaces by age two.
- Sutural (Wormian) bones are very small bones that develop within sutures. Their number and location vary.
- The cranial vault denotes the top, sides, front, and back of the cranium. The cranial floor (base) denotes the bottom of the cranium.
- Cranial fossae are three depressions in the floor of the cranium. These fossae, called the anterior, middle, and posterior cranial fossae, provide spaces that accommodate the shape of the brain.
- The nasal cavity is formed by cartilage and several bones. Air entering the cavity is warmed and cleansed by mucus lining the cavity.
- Sinuses (paranasal sinuses) are mucus‐lined cavities inside cranial and facial bones that surround the nasal cavity. The cavities secrete mucus that drains into the nasal cavity. The cavities also act as resonance chambers that enhance vocal (and singing) quality.
Figure 1.The right lateral view and anterior view of the skull's bones
figure 2.The sagittal section and interior view of the skull's bones
