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The dura mater has two layers, an outer periosteal layer closely adhered to the neurocranium, and an inner meningeal layer known as the dural border cell layer. [1] The two dural layers are for the most part fused together forming a thick fibrous tissue membrane that covers the brain and the vertebrae of the spinal column. [2]
The cranial cavity, also known as intracranial space, is the space within the skull that accommodates the brain.The skull is also known as the cranium. [1] The cranial cavity is formed by eight cranial bones known as the neurocranium that in humans includes the skull cap and forms the protective case around the brain.
The calvaria is made up of the superior portions of the frontal bone, occipital bone, and parietal bones. [1] In the human skull, the sutures between the bones normally remain flexible during the first few years of postnatal development, and fontanelles are palpable. Premature complete ossification of these sutures is called craniosynostosis.
Brain cells make up the functional tissue of the brain. The rest of the brain tissue is the structural stroma that includes connective tissue such as the meninges , blood vessels , and ducts. The two main types of cells in the brain are neurons , also known as nerve cells, and glial cells , also known as neuroglia. [ 1 ]
The upper areas of the cranial bones form the calvaria (skullcap). The facial skeleton (membranous viscerocranium) is formed by the bones supporting the face, and includes the mandible . The bones of the skull are joined by fibrous joints known as sutures— synarthrodial (immovable) joints formed by bony ossification , with Sharpey's fibres ...
The open portion between the major bones of the upper part of the vault, called fontanelles, normally remain soft up to two years after birth. As the fontanelles close, the vault loses some of its plasticity. The sutures between the bones remain until 30 to 40 years of age, allowing for growth of the brain. Cranial vault size is directly ...
The neural crest runs the length of the tube with cranial neural crest cells at the cephalic end and caudal neural crest cells at the tail. Cells detach from the crest and migrate in a craniocaudal (head to tail) wave inside the tube. [67] Cells at the cephalic end give rise to the brain, and cells at the caudal end give rise to the spinal cord ...
Visually, the interior of the brain consists of areas of so-called grey matter, with a dark color, separated by areas of white matter, with a lighter color. Further information can be gained by staining slices of brain tissue with a variety of chemicals that bring out areas where specific types of molecules are present in high concentrations.