NASAL CAVITY. 



803 



part of which the sphenoidal, air- sinus opens. The superior meatus of the nose is a 

 short oblique fissure, directed downwards and backwards, under cover of the superior 

 nasal concha ; into it the posterior ethmoidal cells open by one or more orifices. 

 A small meatus, bounded superiorly by a 

 concha suprenaa, frequently exists above 

 the superior meatus. The narrow slit-like 

 interval between the nasal septum and the 

 medial surface of the middle nasal concha 

 is named the olfactory cleft or sulcus. 



The middle meatus, situated below and 

 lateral to the middle nasal concha, is a 

 roomy passage, and is continued forwards 

 into a slightly depressed area, termed the 

 atrium meatus nasi, which lies immediately 

 above the vestibule. The atrium is limited Vomero . n 

 superiorly and anteriorly by a low ridge, cartilages 



the agger nasi, the representative of the FlG> 673 ._ SECTION THBOUGH NOSE'OF A KITTEN, 

 naso-turbinal found in many animals. When showing position of the vomero-nasai organs. 

 the middle nasal concha has been removed 



the lateral wall of the meatus is exposed. On it is seen a narrow semilunar 

 cleft, the hiatus semilunaris, bounded above by a rounded elevation, the bulla 

 ethmoidalis, and below by the sharp edge of the processus uncinatus of the 



Vomero-nasal organs 



Frontal air-sinus 



Bristle passed 



from it into the 



middle meatus 



Opening of middle ethmoidal cells 



Openings of posterior ethmoidal cells 

 Recessus sphenoethmoidalis 



Sphenoidal air-sinus 



Cut edge of inferior nasal concha 

 Bristle in opening of naso-lacrimal duct 



FIG. 674. VIEW OF THE LATERAL WALL OP THE NOSE THE NASAL CONCHA HAVING BEEN REMOVED. 



1. Vestibule. 



2. Opening of maxillary sinus. 



3. Hiatus semilunaris. 



4. Bulla ethmoidalis. 7. Cut edge of superior nasal concha. 



5. Agger nasi. 8. Cut edge of middle nasal concha. 



6. Opening of anterior ethmoidal cells. 9. Pharyngeal orifice of auditory tube. 



ethmoid. The size of the bulla varies with that of the middle ethmoidal cells, 

 which are contained within it and which open on or near its upper surface. 

 Through the hiatus semilunaris the middle meatus opens into the infundibulum, 

 a curved channel, limited above by the bulla ethmoidalis, and below by the lateral 

 surface of the processus uncinatus. The anterior end of the infundibulum receives 



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