Skull

The skull (cranium) bones are made up of eight cranial and fourteen facial bones. The skull contains numerous cavities these being the cranial cavity (the largest of all), the nasal cavity, middle and inner ear chambers and the two bony orbits. The latter that houses the eyeballs is actually formed by facial and cranial bones. The bones of the skull are partitioned into two parts, the vault and the base. The vault, which is also known, as the calvarium, is the upper rounded dome like portion. It is made up of the frontal bone, two parietal bones, two temporal bones, an occipital bone, a sphenoid bone and an ethmoid bone. The base refers to the irregular portion located below the vault. The base of the skull is made up of the basal portion of the frontal bone, the ethmoid, the sphenoid and the basal portion of the occipital bone. The contour of the base of the skull is irregular and rough as opposed to the contour of the vault of the skull that is a smooth convex surface. The skull base is also perforated with passages for cranial nerves and blood vessels to pass through. The base of the skull also contains the foramen magnum, which is a large opening of the occipital bone that provides a passageway for the lower portion of the brainstem, as it becomes the upper portion of the spinal cord. The vault and base are separated by what is termed sutures of the skull. These sutures are made up of membranous tissue and cartilage. The four prominent skull sutures are the coronal suture, the sagittal suture, the lamboidal suture and the squamosal suture. The coronal suture unites the frontal bone with the two parietal bones. The sagittal suture unites the bones at the midline. The lamboidal suture separates the parietal and occipital bones. The squamosal suture is located between the parietal and temporal bones