View source for Vomer

{{Short description|Unpaired facial bone of the skull}}
{{Infobox bone
| Name        = Vomer
| Latin       = vomer
| Image       = Illu facial bones.jpg
| Caption     = Vomer labeled at left.
| Image2      = Gray854.png
| Caption2    = Bones and cartilages of septum of nose. Right side. (Vomer visible at bottom left.)
}}
The '''vomer''' ({{IPAc-en|ˈ|v|oʊ|m|ər}};<ref>''[[OED]]'' 2nd edition, 1989.</ref><ref>[http://www.merriam-webster.com/dictionary/vomer Entry "vomer"] in ''[http://www.merriam-webster.com/ Merriam-Webster Online Dictionary]''.</ref> {{langx|la|vomer|lit=ploughshare}}) is one of the unpaired [[facial skeleton|facial bones]] of the [[human skull|skull]]. It is located in the midsagittal line, and [[Articulation (anatomy)|articulates]] with the [[sphenoid bone|sphenoid]], the [[ethmoid bone|ethmoid]], the left and right [[palatine bone|palatine]] bones, and the left and right [[maxillary bone|maxillary]] bones. The vomer forms the inferior part of the [[nasal septum]] in humans, with the superior part formed by the [[perpendicular plate of ethmoid bone|perpendicular plate of the ethmoid bone]].<ref>Illustrated Anatomy of the Head and Neck, Fehrenbach and Herring, Elsevier, 2012, page 52</ref> The name is derived from the Latin word for a ploughshare and the shape of the bone.

== In humans ==
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]]; it has two surfaces and four borders.

The surfaces are marked by small furrows for [[blood vessel]]s, and on each is the '''vomerine groove''' (also ''nasopalatine groove'' or ''Scarpa's sulcus''), which runs obliquely downward and forward, and lodges the [[nasopalatine nerve]] (also ''Scarpa's nerve'') 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 (anatomy)|rostrum]] of the [[sphenoid bone|sphenoid]], while the margins of the alae articulate with the vaginal processes of the [[medial pterygoid plate]]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]]s.

The ''anterior border'' is the longest and slopes downward and forward. Its upper half is fused with the [[perpendicular plate of ethmoid bone|perpendicular plate]] of the [[ethmoid]]; its lower half is grooved for the inferior margin of the [[Septal nasal cartilage|septal cartilage of the nose]].

The ''posterior border'' is free of bony articulation, having no muscle attachments. It is concave, separates the [[choana]]e, and is thick and bifid above, thin below.

=== Articulations ===
The human vomer [[Articulation (anatomy)|articulates]] with six bones:
* two of the cranium, the [[sphenoid bone|sphenoid]] and [[ethmoid bone|ethmoid]].
* four of the face, two [[maxilla]]e; and two [[palatine bone]]s.

It also articulates with the septal cartilage of the nose.

== Vomeronasal organ ==
The [[vomeronasal organ]], also called Jacobson's organ, is a [[chemoreceptor]] organ named for its closeness to the vomer and [[nasal bone]]s, and is particularly developed in animals such as cats (who adopt a characteristic pose called the ''[[Flehmen reaction]]'' or ''flehming'' when making use of it), and is thought to have to do with the perception of certain [[pheromone]]s.

== In other animals ==
In [[Osteichthyes|bony fish]], the vomers are flattened, paired, bones forming the anterior part of the roof of the mouth, just behind the [[premaxilla]]ry bones. In many species, they have teeth, supplementing those in the jaw proper; in some [[labyrinthodont]]s (extinct amphibians) the teeth on the vomers were actually larger than the primary set. In [[amphibian]]s and [[reptile]]s, the vomers become narrower, due to the presence of the enlarged [[choana]]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]]s, where they form the upper hind part of the beak, again being located between the choanae.<ref name=VB>{{cite book |author=Romer, Alfred Sherwood|author2=Parsons, Thomas S.|year=1977 |title=The Vertebrate Body |publisher=Holt-Saunders International |location= Philadelphia, PA|pages= 220–243|isbn= 0-03-910284-X}}</ref>

In some living [[salamander]]s, including the [[Necturus|mudpuppy]], the [[maxilla]] is absent and therefore the vomerine teeth fulfill a major functional role in the upper jaw.<ref>{{Cite book |author=Holman, J. Alan |url=http://worldcat.org/oclc/62732645 |title=Fossil salamanders of North America |date=2006 |publisher=Indiana University Press |isbn=0-253-34732-7 |oclc=62732645}}</ref>

In [[mammal]]s, the vomers have become narrower still, and are fused into a single, vertically oriented bone. The development of the [[hard palate]] beneath the vomer means that the bone is now located in a nasal chamber, separate from the mouth.<ref name=VB/>

== Additional images ==
<gallery>
 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
</gallery>

== See also ==
* {{annotated link|Choana}}

{{Portal|Anatomy}}
{{Anatomy-terms}}

== References ==
{{Gray's}}
{{Reflist}}

== External links ==
{{Commons category|Vomer}}
* {{SUNYAnatomyLabs|33|st|02|32}} – "Nasal Cavity: Bones"
* {{SUNYAnatomyFigs|33|02|03}} – "Diagram of skeleton of medial (septal) nasal wall."
* {{NormanAnatomy|lesson9}} ({{NormanAnatomyFig|nasalseptumbonescarti}})
* {{UMichAtlas|rsa1p7}} – "Nasal septum, lateral view"
* {{cite web|url=http://www.tk.de/rochelexikon/pics/s34256.000-1.html|title=Anatomy diagram: 34256.000-1|work= Roche Lexicon – illustrated navigator|publisher= Elsevier|archive-url=https://web.archive.org/web/20121227145535/http://www.tk.de/rochelexikon/pics/s34256.000-1.html|archive-date=2012-12-27}}
* {{cite web|url=http://www.tk.de/rochelexikon/pics/s34257.000-1.html|title=Anatomy diagram: 34257.000-1|work= Roche Lexicon – illustrated navigator|publisher= Elsevier|archive-url=https://web.archive.org/web/20120722052131/http://www.tk.de/rochelexikon/pics/s34257.000-1.html|archive-date=2012-07-22}}

{{Facial bones}}{{Tetrapod osteology}}{{Authority control}}

[[Category:Bones of the head and neck]]
[[Category:Irregular bones]]
[[Category:Facial bones]]
[[Category:Flat bones]]