Mesethmoid


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Related to Mesethmoid: mesethmoid bone

Mes`eth´moid


a.1.(Anat.) Of or pertaining to the middle of the ethmoid region or ethmoid bone.
References in periodicals archive ?
In the marabou stork, air flow passes into a mass of trabecular bone within the mesethmoid bones over a sheet of muscle attached to the left palatine bone cranial to the orbit and continues beneath the left eyeball, leaving the orbit by an opening in the orbital floor which gives direct access to the ventral air pouch (Fig 3).
One of the few variations in this bone among species of Neomorphinae is found in Neomorphus geoffroyi, Morococcyx and Geococcyx, where the dorsal process is less developed and is partially fused with the mesethmoid, thus providing a large aperture for the medial orbitonasal foramen.
2): posterodorsal portion of mesethmoid (or of supraethmoid) being markedly compressed transversally when seen in dorsal view (34: 0 [right arrow] 1, not reverted within taxa examined of this clade C13, but occurring independently in some groups outside the clade, e.
These synapomorphies are: presence of anterolateral processes of mesethmoid supporting and/or articulating with premaxillae (33: 0 [right arrow] 1, occurring independently outside this clade C18 in a few groups, and reverted, inside of this clade, in the aulopiforms; the members of the genus Coregonus might display either CS0 or CS1 of this character); parapophyses of two first free vertebrae not fused to centra (75: 0 [right arrow] 1, occurring in a few groups outside of this clade C18, and reverted, inside this clade, in Aulopus and Astronesthes); supramaxillae present as independent ossifications (158: 1 [right arrow] 0, occurring in various groups outside of this clade C18, but not reverted inside of it, although it should be noted that Astronesthes and Stomias were coded as '?
A monogeneric atheriniform family with the parasphenoid concave rather than convex, parasphenoid myodomes present; mesethmoid morphology unique, nasal septum formed by ethmoid and mesethmoid; parietals not contributing to posttemporal fossa; anterior vertebral parapophyses with lateral ridges; interdorsals absent; cleithrum dorsal enclosure absent; membrane just posterior to genital opening; and pelvic posteromedial process elongate.
3 times in base of the cranium; preocular, postocular, tympanic and parietal spines present, but small and weak; nuchal spines sometimes present; supraocular and coronal spines absent; cranial ridges absent except for the parietal ridges which are low but never scaled over; parietals separated; mesethmoid processes never directed upward; base of cranium markedly curved; ventral process of basisphenoid feeble, never attached to the parasphenoid; nasal spines low, but strong; preorbital lobes without spines; second suborbital bone much wider than long.
Without mesethmoid cartilage along dorsal and lateral margins, but with cartilage along anterior and dorsal margin of parasphenoid.
Development of dorsal mesethmoid spine at the anterior margin of external nares, between angles of premaxillaries: 1- elevation of the ossified portion of the mesethmoid to, or near to the level of the dorsal surfaces of the premaxillaries; 2- no such elevation.
0] Does not situate well posteriorly to anteroventral margin of mesethmoid (or of supraethmoid and/or rostrodermethmoids: see above) (e.