The facial skeleton comprises the facial bones that may attach to build a portion of the skull.
In human anatomy and development, the facial skeleton is sometimes called the membranous viscerocranium, which comprises the human mandible and dermatocranium elements that are not part of the braincase.
Structure
In the
human skull, the facial skeleton consists of fourteen bones in the
face:
Variations
Elements of the
cartilaginous viscerocranium (i.e.,
splanchnocranium elements), such as the
hyoid bone, are sometimes considered part of the facial skeleton. The
ethmoid bone (or a part of it) and also the
sphenoid bone are sometimes included, but otherwise considered part of the
neurocranium. Because the maxillary bones are fused, they are often collectively listed as only one bone. The mandible is generally considered separately from the cranium.
Development
The facial skeleton is composed of
dermal bone and derived from the
neural crest cells (also responsible for the development of the
neurocranium,
human teeth and
adrenal medulla) or from the
sclerotome, which derives from the
somite block of the
mesoderm. As with the neurocranium, in
Chondricthyes and other cartilaginous vertebrates, they are not replaced via endochondral ossification.
Variation in craniofacial form between humans is largely due to differing patterns of biological inheritance. Cross-analysis of osteological variables and genome-wide SNPs has identified specific genes that control this craniofacial development. Of these genes, DCHS2, RUNX2, GLI3, PAX1 and PAX3 were found to determine human nose, whereas EDAR impacts chin protrusion.
==Additional images==
(labeled as "Brain case").]]
See also
External links
