Facial skeleton

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Facial bones
Facial skeleton - en.svg
The fourteen bones that form the human facial skeleton
Facial bones - animation02.gif
The fourteen facial bones. (Neurocranium is shown in semi-transparent.)
  Blue: Vomer (1)
  Yellow: Maxilla (2)
  Purple: Mandible (1)
  Pink: Nasal bones (2)
  Red: Palatine bones (2)
  Bright blue: Lacrimal bones (2)
  Dark green: Zygomatic bones (2)
  Bright green: Inferior nasal concha (2)
Details
Part of Face, skeleton
Identifiers
Latin ossa faciei, ossa facialia
TA98 A02.1.00.008
TA2 355, 356
FMA 53673
Anatomical terms of bone

The facial skeleton comprises the facial bones that may attach to build a portion of the skull. [1] The remainder of the skull is the neurocranium.

Contents

In human anatomy and development, the facial skeleton is sometimes called the membranous viscerocranium, which comprises the mandible and dermatocranial elements that are not part of the braincase.

Structure

In the human skull, the facial skeleton consists of fourteen bones in the face: [1] [2]

Variations

Elements of the cartilaginous viscerocranium (i.e., splanchnocranial 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, 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 nasal morphology, whereas EDAR impacts chin protrusion. [3]

Additional images

See also

Related Research Articles

<span class="mw-page-title-main">Face</span> Part of the body that is at the front of the head

The face is the front of an animal's head that features the eyes, nose and mouth, and through which animals express many of their emotions. The face is crucial for human identity, and damage such as scarring or developmental deformities may affect the psyche adversely.

<span class="mw-page-title-main">Skull</span> Bony structure that forms the head in vertebrates

The skull is a bone protective cavity for the brain. The skull is composed of four types of bone i.e., cranial bones, facial bones, ear ossicles and hyoid bone. However two parts are more prominent: the cranium and the mandible. In humans, these two parts are the neurocranium and the viscerocranium that includes the mandible as its largest bone. The skull forms the anterior-most portion of the skeleton and is a product of cephalisation—housing the brain, and several sensory structures such as the eyes, ears, nose, and mouth. In humans these sensory structures are part of the facial skeleton.

<span class="mw-page-title-main">Maxilla</span> Upper jaw bone

The maxilla in vertebrates is the upper fixed bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. The two maxillary bones are fused at the intermaxillary suture, forming the anterior nasal spine. This is similar to the mandible, which is also a fusion of two mandibular bones at the mandibular symphysis. The mandible is the movable part of the jaw.

<span class="mw-page-title-main">Ethmoid bone</span> Bone in the human skull

The ethmoid bone is an unpaired bone in the skull that separates the nasal cavity from the brain. It is located at the roof of the nose, between the two orbits. The cubical bone is lightweight due to a spongy construction. The ethmoid bone is one of the bones that make up the orbit of the eye.

<span class="mw-page-title-main">Sphenoid bone</span> Bone at the front of the skull

The sphenoid bone is an unpaired bone of the neurocranium. It is situated in the middle of the skull towards the front, in front of the basilar part of the occipital bone. The sphenoid bone is one of the seven bones that articulate to form the orbit. Its shape somewhat resembles that of a butterfly or bat with its wings extended.

<span class="mw-page-title-main">Lacrimal bone</span> Smallest and most fragile bone of the human skull and face

The lacrimal bone is a small and fragile bone of the facial skeleton; it is roughly the size of the little fingernail. It is situated at the front part of the medial wall of the orbit. It has two surfaces and four borders. Several bony landmarks of the lacrimal bone function in the process of lacrimation or crying. Specifically, the lacrimal bone helps form the nasolacrimal canal necessary for tear translocation. A depression on the anterior inferior portion of the bone, the lacrimal fossa, houses the membranous lacrimal sac. Tears or lacrimal fluid, from the lacrimal glands, collect in this sac during excessive lacrimation. The fluid then flows through the nasolacrimal duct and into the nasopharynx. This drainage results in what is commonly referred to a runny nose during excessive crying or tear production. Injury or fracture of the lacrimal bone can result in posttraumatic obstruction of the lacrimal pathways.

<span class="mw-page-title-main">Axial skeleton</span> Part of the skeleton that consists of the bones of the head and trunk of a vertebrate

The axial skeleton is the part of the skeleton that consists of the bones of the head and trunk of a vertebrate. In the human skeleton, it consists of 80 bones and is composed of six parts; the skull, also the ossicles of the middle ear, the hyoid bone, the rib cage, sternum and the vertebral column. The axial skeleton together with the appendicular skeleton form the complete skeleton. Another definition of axial skeleton is the bones including the vertebrae, sacrum, coccyx, skull, ribs, and sternum.

In anthropology, Sinodonty and Sundadonty are two patterns of features widely found in the dentitions of different populations in East Asia and Southeast Asia. These two patterns were identified by anthropologist Christy G. Turner II as being within the greater "Mongoloid dental complex".

<span class="mw-page-title-main">Brow ridge</span> Bony ridge located above the eye sockets of all primates

The brow ridge, or supraorbital ridge known as superciliary arch in medicine, is a bony ridge located above the eye sockets of all primates and some other animals. In humans, the eyebrows are located on their lower margin.

<span class="mw-page-title-main">Pharyngeal arch</span> Embryonic precursor structures in vertebrates

The pharyngeal arches, also known as visceral arches, are structures seen in the embryonic development of vertebrates that are recognisable precursors for many structures. In fish, the arches are known as the branchial arches, or gill arches.

<span class="mw-page-title-main">Forensic facial reconstruction</span> Recreating faces from skeletal remains

Forensic facial reconstruction is the process of recreating the face of an individual from their skeletal remains through an amalgamation of artistry, anthropology, osteology, and anatomy. It is easily the most subjective—as well as one of the most controversial—techniques in the field of forensic anthropology. Despite this controversy, facial reconstruction has proved successful frequently enough that research and methodological developments continue to be advanced.

Ectodysplasin A receptor (EDAR) is a protein that in humans is encoded by the EDAR gene. EDAR is a cell surface receptor for ectodysplasin A which plays an important role in the development of ectodermal tissues such as the skin. It is structurally related to members of the TNF receptor superfamily.

<span class="mw-page-title-main">Neurocranium</span> Upper and back part of the skull, which forms a protective case around the brain

In human anatomy, the neurocranium, also known as the braincase, brainpan, or brain-pan is the upper and back part of the skull, which forms a protective case around the brain. In the human skull, the neurocranium includes the calvaria or skullcap. The remainder of the skull is the facial skeleton.

<span class="mw-page-title-main">Endocranium</span> The lower and inner parts of the skull

The endocranium in comparative anatomy is a part of the skull base in vertebrates and it represents the basal, inner part of the cranium. The term is also applied to the outer layer of the dura mater in human anatomy.

Viscerocranium may refer to one of two related concepts:

<span class="mw-page-title-main">Skull roof</span> Roofing bones of the skull

The skull roof, or the roofing bones of the skull, are a set of bones covering the brain, eyes and nostrils in bony fishes and all land-living vertebrates. The bones are derived from dermal bone and are part of the dermatocranium.

A facial cleft is an opening or gap in the face, or a malformation of a part of the face. Facial clefts is a collective term for all sorts of clefts. All structures like bone, soft tissue, skin etc. can be affected. Facial clefts are extremely rare congenital anomalies. There are many variations of a type of clefting and classifications are needed to describe and classify all types of clefting. Facial clefts hardly ever occur isolated; most of the time there is an overlap of adjacent facial clefts.

<span class="mw-page-title-main">DCHS2</span> Protein-coding gene in the species Homo sapiens

Protein dachsous homolog 2, also known as protocadherin-23 (PCDH23) or cadherin-27 (CDH27), is a protein that in humans is encoded by the DCHS2 gene.

The development of craniofacial growth is a complicated phenomenon that has been the subject of much research for past 70 years. From the first theory in 1940s, many different ideas pertaining to how a face develops has intrigued the minds of researchers and clinicians alike.

References

  1. 1 2 Jinkins, J. Randy (2000). Atlas of Neuroradiologic Embryology, Anatomy, and Variants. Lippincott Williams & Wilkins. p. 458. ISBN   0-7817-1652-7 . Retrieved 24 August 2017.
  2. "Divisions of the Skeleton". U.S. National Cancer Institute's Surveillance, Epidemiology and End Results (SEER) Program. Archived from the original on 14 January 2009. Retrieved 24 August 2017.{{cite web}}: CS1 maint: bot: original URL status unknown (link)
  3. Adhikari K, Fuentes-Guajardo M, Quinto-Sánchez M, Mendoza-Revilla J, Chacón-Duque JC, Acuña-Alonzo V, Gómez-Valdés J (2016). "A genome-wide association scan implicates DCHS2, RUNX2, GLI3, PAX1 and EDAR in human facial variation". Nature Communications. 7: 11616. Bibcode:2016NatCo...711616A. doi:10.1038/ncomms11616. PMC   4874031 . PMID   27193062.