Vomer

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Vomer
Illu facial bones.jpg
Vomer labeled at left.
Gray854.png
Bones and cartilages of septum of nose. Right side. (Vomer visible at bottom left.)
Details
Latin Vomer
Identifiers
Gray's p.170
MeSH A02.165.407.600
TA A02.1.11.001
FMA FMA:9710
Anatomical terms of bone

The vomer (/ˈvmər/[1][2]) is one of the unpaired facial bones of the skull. It is located in the midsagittal line, and articulates with the sphenoid, the ethmoid, the left and right palatine bones, and the left and right maxillary bones. The vomer forms the posterior part of the nasal septum, with the anterior part formed by the ethmoid.[3]

Biology[edit]

The vomeronasal organ, also called Jacobson's organ, is a chemoreceptor organ named for its closeness to the vomer and nasal bones, 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 pheromones.

Anatomical details[edit]

The vomer is situated in the median plane, but its anterior portion is frequently bent to one or other 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 vessels, and on each is the nasopalatine groove, which runs obliquely downward and forward, and lodges the nasopalatine nerve and vessels.

Borders[edit]

The superior border, the thickest, presents a deep furrow, bounded on either side by a horizontal projecting ala of bone; the furrow receives the rostrum of the sphenoid, while the margins of the alæ articulate with the vaginal processes of the medial pterygoid plates 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 bones.

The anterior border is the longest and slopes downward and forward. Its upper half is fused with the perpendicular plate of the 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 and has no muscle attachments, concave, and separates the choanae. It is thick and bifid above, thin below.

Articulations[edit]

The vomer articulates with six bones:

It also articulates with the septal cartilage of the nose.

In other animals[edit]

In bony fish, the vomers are flattened, paired, bones forming the anterior part of the roof of the mouth, just behind the premaxillary bones. In many species, they have teeth, supplementing those in the jaw proper; in some extinct species the teeth on the vomers were actually larger than the primary set. In amphibians and reptiles, the vomers become narrower, due to the presence of the enlarged choanae (the inner part of the nostrils) on either side, and they may extend further back in the jaw. They are typically small in birds, where they form the upper hind part of the beak, again being located between the choanae.[4]

In mammals, 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.[4]

Additional images[edit]

See also[edit]

References[edit]

  1. ^ OED 2nd edition, 1989.
  2. ^ Entry "vomer" in Merriam-Webster Online Dictionary.
  3. ^ Illustrated Anatomy of the Head and Neck, Fehrenbach and Herring, Elsevier, 2012, page 52
  4. ^ a b Romer, Alfred Sherwood; Parsons, Thomas S. (1977). The Vertebrate Body. Philadelphia, PA: Holt-Saunders International. pp. 220–243. ISBN 0-03-910284-X. 

This article incorporates text from a public domain edition of Gray's Anatomy.

External links[edit]