NASAL CAVITIES 



above the bulla is the aperture of the middle ethmoidal 

 cells (Fig. 117). 



Dissection. Open the maxillary sinus from the lateral side, 

 by sawing upwards through the zygomatic process of the maxilla. 

 Then examine the interior of the sinus. 



The orifice by means of which the great maxillary air sinus 

 communicates with the middle meatus lies in the medial wall 

 of the sinus, much nearer the roof than the floor a position 

 highly unfavourable for the escape of fluids which may 

 collect in the cavity. Sometimes, however, a second orifice, 



, Frontal air sinus 



- Bulla ethmoidalis ' 



/Orifice of middle ethmoidal cells 



/Orifices of posterior ethmoidal cells 



Recessus spheno-ethmoidalis 

 /Sphenoidal sinus 



Orifice of anterior 

 ethmoidal cells 



Hiatus semilunar 



Atriun 



Orifice of maxil- 

 lary sinus 



Vestibul 



Orifice of naso-lacrimal duct 



Cut edge of 

 middle concha 



Middle meatus 

 Pharyngeal 



Orifice of 

 auditory tube 

 Salpingo- 

 phary ngeal fold 



Soft palate 



Inferior meatus 



Cut edge of inferior 

 concha 



FIG. 117. Lateral wall of Nasal Cavity and Naso-pharynx. 

 The three conchas have been removed. 



circular in outline, will be found. If it is present it is situated 

 lower down, and it opens into the middle meatus, immediately 

 above the middle point of the attached margin of the inferior 

 concha. 



The dissector should note that, on account of the relation- 

 ship of the infundibulum to the hiatus semilunaris and of the 

 latter to the opening of the maxillary sinus, there is a 

 tendency, in some cases, for the secretion of the frontal 

 sinuses to flow into the maxillary sinus. 



The inferior meatus is the horizontal passage which lies 

 between the inferior concha and the floor and lateral wall 



