Neurocranium

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Neurocranium
Cranial bones en v2.svg
The eight bones that form the human neurocranium.
Neurocranium - animation02.gif
The eight cranial bones. (Facial bones are shown in semi-transparent.)
  Yellow: Frontal bone (1)
  Blue: Parietal bone (2)
  Purple: Sphenoid bone (1)
  Orange: Temporal bone (2)
  Green: Occipital bone (1)
  Red: Ethmoid bone (1)
Details
Identifiers
Latin Neurocranium
Dorlands
/Elsevier
c_60/12264811
TA A02.1.00.007
FMA 53672
Anatomical terms of bone

In mammals, the neurocranium, also known as the braincase, brainpan, or brain-pan[1][2] is the upper and back part of the skull.

The skull can be divided into two parts: the neurocranium, which forms a protective case around the brain, and the facial skeleton, which forms the skeleton of the face.[3]

In the human skull, the neurocranium includes the calvaria, or skullcap. The lower part of the skull is the facial skeleton also known as the splanchnocranium.

Structure[edit]

The neurocranium is divided into two portions:

In humans, the neurocranium is usually considered to include the following eight bones:

The ossicles (three on each side) are usually not included as bones of the neurocranium.[5] There may variably also be extra sutural bones present.

Below the neurocranium is a complex of openings (foramina) and bones, including the foramen magnum which houses the neural spine. The auditory bullae, located in the same region, aid in hearing.[6]

The size of the neurocranium is variable among mammals. The roof may contain ridges such as the temporal crests.

Development[edit]

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.

Other animals[edit]

The neurocranium is formed by the endocranium, the lower portions of the cranial vault, and the skull roof. These are not fused in fishes, and a proper neurocranium is only found in land vertebrates.

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.

Additional images[edit]

See also[edit]

References[edit]

  1. ^ "Brainpan - Medical Definition and More from Merriam-Webster". Merriam-Webster/Medical. 
  2. ^ Nyiszli, Miklos (2011). Auschwitz: A Doctor's Eyewitness Account. New York: Arcade Publishing. 
  3. ^ a b Sadler, Thomas W. (February 2009). Langman's Medical Embryology. Lippincott Williams & Wilkins. p. 173. ISBN 0781790697. 
  4. ^ In small children, the frontal bone is still separated into two parts, by the frontal suture, which normally closes during postnatal development.
  5. ^ but if they are included, the neurocranium will then have to be said to consist of fourteen bones
  6. ^ Elbroch, M. 2006. Animal skulls: A guide to North American species. Stackpole Books, pp. 20–22. ISBN 978-0-8117-3309-0