NASAL CAVITIES 



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sphenoid, and also of the ala of the vomer, the sphenoidal 

 process of the palate bone, and the vaginal process of the 

 medial pterygoid lamina, all of which are applied to the inferior 

 surface of the body of the sphenoid. 



The floor of the nasal cavity is of considerable width. It is 

 formed by the palatal processes of the maxilla and the palate 

 bones, and is concave from side to side. Further, it presents 



Anterior 

 ethmoidal cell 



Infuudibulum 



Posterior angle of 



septal cartilage 



between vomer. 



and perpendicular 



lamina of ethmoid 



Middle meatu 

 Middle conch 



Maxillary 

 sinus 



Inferior meatus 



Inferior concha 



FIG. 115. Posterior aspect of Frontal section through the Nasal 

 Cavities opposite the Crista Galli of the Ethmoid Bone. 



The upper arrow shows the opening of an anterior ethmoidal cell into the hiatus 

 semilunaris. The lower arrow passes from the maxillary sinus into the hiatus 

 semilunaris. 



a gentle antero-posterior slope, being slightly higher anteriorly 

 than posteriorly. On the anterior part of the floor, and close 

 to the septum nasi, the dissector may see a minute funnel- 

 shaped depression of the muco-periosteum leading into the 

 incisive foramen. The depression is of interest from a 

 developmental point of view ; for it is a vestige of the 

 extensive communication which existed in the embryo between 

 the cavities of the nose and the mouth. 



