mesethmoid


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Related to mesethmoid: mesethmoid bone

mesethmoid

[me′zeth‚mȯid]
(anatomy)
A bone or cartilage in the center of the ethmoid region of the vertebrate skull; usually constitutes the greater portion of the nasal septum.
References in periodicals archive ?
Ethmomaxillary ligament originating on mesethmoid, inserting on maxilla dorsal process.
Some of the character states in Notocheirus (including lack of first dorsal, mesethmoid, first epibranchial and epural) could be interpreted as paedomorphism (eg.
A 3 Mesethmoid absent, nasal cavities separated by ethmoid (Said, 1983).
pachycephalus: "Cranium very thick and heavy; interorbital space deeply concave, about 3 1/2 in base of cranium; cranial spines broad and stout, the pointed tips directed backward; preocular, postocular, tympanic and parietal spines present; supraocular, coronal and nuchal spines absent; supraocular ridges exceedingly high and stout, forming a narrow flat area between them; frontal ridges barely evident, can not be seen without elimination of the skin; parietal ridges broad and high, but a little lower than the supraocular ridges; nasal spines stout, directed upward and slightly backward; mesethmoid processes strongly compressed, directed forward and upward; parietal bones separated; base of cranium straight; ventral process of basisphenoid entirely meeting the parasphenoid.
3 times in base of the cranium; cranial spines well developed, directed straightly backward; preocular, postocular, tympanic and parietal spines always present supraocular, corneal and nuchal spines absent; parietal ridges high and naked; frontal ridges low but distinct, the space between them shallowly concave; supraocular edges low or depressed, as high as or lower than the frontal ridges; mesethmoid processes slightly elevated upward; base of cranium some-what curved; parietals separated or partly meeting; ventral process of the basisphenoid well developed, entirely meeting the parasphenoid.
The present subgenus is closely related to Hispaniscus, but differs from it in having a much longer and wider inoterorbital space, elevated mesethmoid processes and shallowly depressed area between the frontal ridges.
7 times in base of cranium; postocular, tympanic and parietal spines present, directed backward and downward; preocular supraocular, coronal and nuchal spines entirely absent; parietal ridges low but broad; supraocular edges depressed, never higher than the frontal ridges; frontal ridges low, the space between them flattish, never deeply concave; mesethmoid processes directed forward and upward; parietals meeting or narrowly separated; the patch of vomerine teeth triangular; base of cranium straight; ventral process of basisphenoid meeting the parasphenoid.