![]() ![]() Similarly, all of the blood vessels supplying the head and neck structures pass through these same foramina or between natural spaces between adjacent bones, called fissures. The main function of the cranium is to encase and protect the brain.Īll of the sensory nerve cells running from the body to the brain, and all of the motor nerves running from the brain to the body have to pass in and out of this bony cavity, and they do so through many natural openings in the underside of the cranium, called foramina (singular – foramen). Reproduced with permission from John Wiley & Sons, Ltd.) Levison’s Textbook for Dental Nurses, 10th edn. ![]() The skull and cranial bones are illustrated in Figure 7.1.įigure 7.1 Skull and cranial bones. Ethmoid bone – single plate at the lower front of the cranium, immediately behind the nose.Sphenoid bone – single plate forming the majority of the base of the cranium.Occipital bone – single plate at the back and partial underside of the cranium.Temporal bones – pair of fan-shaped plates in the temple region of the lower sides of the cranium, in front of the ears.Parietal bones – pair of plates forming the top and the greater area of the sides of the cranium.Frontal bone – single plate at the front of the cranium above the eyes, forming the forehead.The cranium is composed of eight bones, which are separated by the cranial sutures – these are visible on a dry skull as the zig-zagged joints between the bony plates. The base of the cranium articulates with the topmost bone of the vertebral column, the atlas, allowing nodding movements of the head.Īt birth and during infancy, the bony plates making up the cranium are separated from each other by two natural membrane covered spaces called fontanelles, which allow growth of the brain without bony restriction.īy the age of 18 months the fontanelles should have closed, following the natural growth together of the bony plates making up the cranium. Face – the front vertical part of the skull, containing the orbital, nasal and oral cavities and the jawsĪll of the bones of the skull except the lower jaw, the mandible, are fixed to each other by immovable joints called sutures.Cranium – the hollow cavity that surrounds the brain.The skull is the topmost part of the bony skeleton of the body, the head, and is made up of two main areas: ![]()
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