The eight bones that form the human neurocranium.
|Anatomical terms of bone|
In the human skull, the neurocranium includes the calvaria, or skullcap. The lower part of the skull is the splanchnocranium.
Evolutionarily, the human neurocranium has expanded from comprising the back part of the mammalian skull to being also the upper part: during the evolutionary expansion of the brain, the neurocranium has overgrown the splanchnocranium. The upper-frontmost part of the cranium also houses the evolutionarily newest part of the human brain, the frontal lobes.
The term "cranium" can be ambiguous in that it can refer to the neurocranium alone or to the whole skull (the neurocranium and the facial skeleton).
The size of the braincase is variable among mammals. The roof may contain ridges such as the temporal crests. Below the braincase is a complex of foramina (openings) and bones, including the foramen magnum which houses the neural spine. The auditory bullae, located in the same region, aid in hearing.
The neurocranium is divided into two portions:
(a) the membranous part, consisting of flat bones, which surround the brain as a vault; and
Human neurocranial bones
In humans, the neurocranium is usually considered to include the following eight bones:
The neurocranium arises from paraxial mesoderm. There is also some contribution of ectomesenchyme. In Chondrichthyes and other cartilaginous vertebrates this portion of the cranium does not ossify; it is not replaced via endochondral ossification.
- Sadler, Thomas W. (February 2009). Langman's Medical Embryology. Lippincott Williams & Wilkins. p. 173. ISBN 0781790697.
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- Nyiszli, Miklos (2011). Auschwitz: A Doctor's Eyewitness Account. New York: Arcade Publishing.
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- In small children, the frontal bone is still separated into two parts, by the frontal suture, which normally closes during postnatal development.
- but if they are included, the neurocranium will then have to be said to consist of fourteen bones
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