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The vomer () is one of the unpaired
facial bones The facial skeleton comprises the ''facial bones'' that may attach to build a portion of the skull The skull is a bone A bone is a Stiffness, rigid tissue (anatomy), tissue that constitutes part of the vertebrate skeleton in animals. Bones ...
of the
skull The skull is a bone A bone is a rigid tissue Tissue may refer to: Biology * Tissue (biology), an ensemble of similar cells that together carry out a specific function * ''Triphosa haesitata'', a species of geometer moth found in North A ...

skull
. It is located in the midsagittal line, and articulates with the
sphenoid
sphenoid
, the
ethmoid The ethmoid bone (; from Greek ''ethmos'', "sieve") is an unpaired bone in the human skull, skull that separates the nasal cavity from the brain. It is located at the roof of the human nose, nose, between the two Orbit (anatomy), orbits. The cubic ...
, the left and right
palatine A palatine or palatinus (in Latin; plural ''palatini''; cf. derivative spellings below) is a high-level official attached to imperial or royal courts in Europe since Roman Empire, Roman times.
palatine
bones, and the left and right maxillary bones. The vomer forms the inferior part of the
nasal septum The nasal septum () separates the left and right airways of the nasal cavity, dividing the two nostrils. It is depressed by the depressor septi nasi muscle. Structure The fleshy external end of the nasal septum is called the columella ...
, with the superior part formed by the perpendicular plate of the ethmoid bone.Illustrated Anatomy of the Head and Neck, Fehrenbach and Herring, Elsevier, 2012, page 52 The name is derived from the Latin word for a ploughshare and the shape of the bone.


Structure

The vomer is situated in the median plane, but its anterior portion is frequently bent to one side. It is thin, somewhat quadrilateral in shape, and forms the hinder and lower part of the
nasal septum The nasal septum () separates the left and right airways of the nasal cavity, dividing the two nostrils. It is depressed by the depressor septi nasi muscle. Structure The fleshy external end of the nasal septum is called the columella ...
; it has two surfaces and four borders. The surfaces are marked by small furrows for
blood vessel The blood vessels are the components of the circulatory system The circulatory system, also called the cardiovascular system or the vascular system, is an organ system An organ system is a biological system A biological system is a comp ...
s, and on each is the nasopalatine groove, which runs obliquely downward and forward, and lodges the
nasopalatine nerve One branch of the pterygopalatine ganglion (trigeminal nerve, maxillary nerve, maxillary branch), longer and larger than the others, is named the nasopalatine nerve (sometimes called the long sphenopalatine nerve). It enters the nasal cavity throug ...
and vessels.


Borders

The ''superior border'', the thickest, presents a deep furrow, bounded on either side by a horizontal projecting expansion of bone – called the wing of vomer; the furrow receives the rostrum of the
sphenoid
sphenoid
, while the margins of the alae articulate with the vaginal processes of the
medial pterygoid plate The pterygoid processes of the sphenoid (from Greek ''pteryx'', ''pterygos'', "wing"), one on either side, descend perpendicularly from the regions where the body and the greater wings of the sphenoid bone The sphenoid bone is an unpaired bone ...
s of the sphenoid behind, and with the sphenoidal processes of the palatine bones in front. The ''inferior border'' articulates with the crest formed by the maxillæ and
palatine bone In anatomy Anatomy (Greek ''anatomē'', 'dissection') is the branch of biology concerned with the study of the structure of organisms and their parts. Anatomy is a branch of natural science which deals with the structural organization of livi ...

palatine bone
s. The ''anterior border'' is the longest and slopes downward and forward. Its upper half is fused with the perpendicular plate of the
ethmoid The ethmoid bone (; from Greek ''ethmos'', "sieve") is an unpaired bone in the human skull, skull that separates the nasal cavity from the brain. It is located at the roof of the human nose, nose, between the two Orbit (anatomy), orbits. The cubic ...

ethmoid
; its lower half is grooved for the inferior margin of the septal cartilage of the nose. The ''posterior border'' is free of bony articulation, having no muscle attachments. It is concave, separates the
choana The choanae (singular choana), posterior nasal apertures or internal nostrils are two openings found at the back of the nasal passage between the nasal cavity The nasal cavity is a large, air-filled space above and behind the nose A nose ...
e, and is thick and bifid above, thin below.


Articulations

The vomer articulates with six bones: * two of the cranium, the
sphenoid
sphenoid
and
ethmoid The ethmoid bone (; from Greek ''ethmos'', "sieve") is an unpaired bone in the human skull, skull that separates the nasal cavity from the brain. It is located at the roof of the human nose, nose, between the two Orbit (anatomy), orbits. The cubic ...
. * four of the face, two
maxilla The maxilla (plural: ''maxillae'' ) in vertebrates is the upper fixed (not fixed in Neopterygii) 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 tw ...

maxilla
e; and two
palatine bone In anatomy Anatomy (Greek ''anatomē'', 'dissection') is the branch of biology concerned with the study of the structure of organisms and their parts. Anatomy is a branch of natural science which deals with the structural organization of livi ...

palatine bone
s. It also articulates with the septal cartilage of the nose.


Function

The
vomeronasal organ The vomeronasal organ (VNO), or Jacobson's organ, is the paired auxiliary olfactory Olfaction, or the sense of smell, is the special sense through which smells (or odors) are perceived. It occurs when an odor binds to a olfactory receptor, re ...

vomeronasal organ
, also called Jacobson's organ, is a
chemoreceptor A chemoreceptor, also known as chemosensor, is a specialized sensory receptor Sensory neurons, also known as afferent neurons, are neuron A neuron or nerve cell is an membrane potential#Cell excitability, electrically excitable cell (biology) ...
organ named for its closeness to the vomer and
nasal bone The nasal bones are two small oblong bone A bone is a Stiffness, rigid tissue (anatomy), tissue that constitutes part of the skeleton in most vertebrate animals. Bones protect the various organs of the body, produce red blood cell, red and whi ...

nasal bone
s, and is particularly developed in animals such as cats (who adopt a characteristic pose called the ''
Flehmen reaction The flehmen response (; from German ''flehmen'', to bare the upper teeth, and Upper Saxon German Upper Saxon (german: Obersächsisch, ; ) is an East Central German East Central German (german: Ostmitteldeutsch) is the eastern, non-Franconian ...
'' or ''flehming'' when making use of it), and is thought to have to do with the perception of certain
pheromone A pheromone (from Ancient Greek Ancient Greek includes the forms of the Greek language Greek ( el, label=Modern Greek Modern Greek (, , or , ''Kiní Neoellinikí Glóssa''), generally referred to by speakers simply as Greek (, ...

pheromone
s.


In other animals

In
bony fish Osteichthyes (), popularly referred to as the bony fish, is a diverse taxonomic Taxonomy (general) is the practice and science of classification of things or concepts, including the principles that underlie such classification. The term may al ...

bony fish
, the vomers are flattened, paired, bones forming the anterior part of the roof of the mouth, just behind the
premaxilla The premaxilla (or praemaxilla) is one of a pair of small cranial bones at the very tip of the upper jaw of many animals, usually, but not always, bearing teeth. In humans, they are fused with the maxilla. The "premaxilla" of theria, therian mamma ...
ry bones. In many species, they have teeth, supplementing those in the jaw proper; in some
labyrinthodont Labyrinthodontia (Greek Greek may refer to: Greece Anything of, from, or related to Greece Greece ( el, Ελλάδα, , ), officially the Hellenic Republic, is a country located in Southeast Europe. Its population is approximately 10.7 mil ...
s (extinct amphibians) the teeth on the vomers were actually larger than the primary set. In
amphibian Amphibians are ectothermic, tetrapod vertebrates of the Class (biology), class Amphibia. All living amphibians belong to the group Lissamphibia. They inhabit a wide variety of habitats, with most species living within terrestrial animal, ter ...
s and
reptile Reptiles, as most commonly defined, are the animals in the class Class or The Class may refer to: Common uses not otherwise categorized * Class (biology), a taxonomic rank * Class (knowledge representation), a collection of individuals or ...

reptile
s, the vomers become narrower, due to the presence of the enlarged
choana The choanae (singular choana), posterior nasal apertures or internal nostrils are two openings found at the back of the nasal passage between the nasal cavity The nasal cavity is a large, air-filled space above and behind the nose A nose ...
e (the inner part of the nostrils) on either side, and they may extend further back in the jaw. They are typically small in
bird Birds are a group of warm-blooded vertebrate Vertebrates () comprise all species of animal Animals (also called Metazoa) are multicellular eukaryotic organisms that form the Kingdom (biology), biological kingdom Animalia. With ...

bird
s, where they form the upper hind part of the beak, again being located between the choanae. In
mammal Mammals (from Latin Latin (, or , ) is a classical language A classical language is a language A language is a structured system of communication Communication (from Latin ''communicare'', meaning "to share" or "to be i ...
s, the vomers have become narrower still, and are fused into a single, vertically oriented bone. The development of the
hard palate The hard palate is a thin horizontal bony plate made up of two bones of the facial skeleton The facial skeleton comprises the ''facial bones'' that may attach to build a portion of the skull The skull is a bone A bone is a Stiffness, ri ...
beneath the vomer means that the bone is now located in a nasal chamber, separate from the mouth.


Additional images

Image:Sobo 1909 73.png Image:Sobo 1909 74.png Image:Sobo 1909 75.png Image:Gray173.png, Median wall of left nasal cavity showing vomer ''in situ.'' Image:Gray174.png, The vomer. Image:Gray187.png, Base of skull. Inferior surface. Image:Gray194.png, Sagittal section of skull. File:Rotation Vomer bone.gif File:Vomer.jpg, Vomer File:Slide7qqq.JPG, Vomer


See also

*
Choana The choanae (singular choana), posterior nasal apertures or internal nostrils are two openings found at the back of the nasal passage between the nasal cavity The nasal cavity is a large, air-filled space above and behind the nose A nose ...


References


External links

* – "Nasal Cavity: Bones" * – "Diagram of skeleton of medial (septal) nasal wall." * () * – "Nasal septum, lateral view" * * {{Authority control Bones of the head and neck Irregular bones Facial bones