Facial skeleton

The facial skeleton, splanchnocranium or viscerocranium consists of a part of the skull that is derived from branchial arches. The facial bones are the bones of the anterior and lower skull. The other, dorsal part of the skull is the neurocranium.

Human facial bones

For the human skull, most sources include at least these twelve bones in their lists of facial bones:^[1][2]

• Inferior nasal concha (2)
• Lacrimal bones (2)
• Mandible
• Maxilla
• Nasal bones (2)
• Palatine bone
• Vomer
• Zygomatic bones (2)

Mnemonic

A mnemonic device for this enumeration is: "Virgil Can Not Make My Pet Zebra Laugh" – Vomer, Conchae, Nasal, Maxilla, Mandible, Palatine, Zygomatic, Lacrimal.

Variations

The hyoid bone is sometimes included, and sometimes excluded. The ethmoid bone (or a part of it) is sometimes included, but otherwise considered part of the neurocranium; the same is the case with the sphenoid bone. Some sources describe the maxilla's left and right parts as two bones. Likewise, the palatine bone is also sometimes described as two bones.

Anatomical textbooks differ in what bones they include in their enumerations of the bones of the facial skeleton. Some textbooks make a strict distinction between bones of the neurocranium and viscerocranium, primarily based on the respective bones' embryological origins. Other textbooks are more lenient, maybe in an effort to provide more context or be more comprehensive, and tend to include all the bones that can be seen in a frontal aspect of the human skull in their enumerations of the facial bones; consequently they include bones such as the frontal bone, etc. in their lists, as is also evident in the illustrations on this page.^[3]

More images with facial bones

Embryonic origins

The splanchnocranium is derived from the neural crest cells (also responsible for the development of the neurocranium or, teeth and adrenal medulla) or from scleratone found in the somite block of the mesoderm. As with the neurocranium, in Chondricthyes and other cartilaginous vertebrates, they are not replaced via endochondral ossification. In tetrapods, such as amphibians and reptiles, the columella connecting to the tympanum is derived from the splanchnocranium. In mammals, the splanchnocranium derives the bones of the inner ear, the malleus, the incus and stapes.

References

External links

• ent/9 at eMedicine - "Facial Bone Anatomy"