- Middle meatus
Infobox Bone
Name = Middle meatus
Latin = meatus nasi medius
GraySubject = 57
GrayPage = 195
Caption = Roof, floor, and lateral wall of left nasal cavity. (Middle meatus labeled at center right.)
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DorlandsPre = m_06
DorlandsSuf = 12518245
The middle meatus is a nasal opening or canal situated between themiddle andinferior conchæ , and extends from the anterior to the posterior end of the latter.The lateral wall of this meatus can be satisfactorily studied only after the removal of the
middle concha .On it is a curved fissure, the
hiatus semilunaris , limited below by the edge of theuncinate process of theethmoid and above by an elevation named thebulla ethmoidalis ; themiddle ethmoidal cells are contained within this bulla and open on or near to it.Through the hiatus semilunaris the meatus communicates with a curved passage termed the
infundibulum , which communicates in front with theanterior ethmoidal cells and in rather more than fifty percent of skulls is continued upward as thefrontonasal duct into thefrontal air-sinus ; when this continuity fails, the frontonasal duct opens directly into the anterior part of the meatus.Below the bulla ethmoidalis and hidden by the uncinate process of the ethmoid is the opening of the
maxillary sinus (ostium maxillare); an accessory opening is frequently present above the posterior part of theinferior nasal concha .
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