70 OSTEOLOGY, OR ANATOMY OF OSSEOUS SYSTEM 



nares. They communicate with the sinuses of the frontal, 

 ethmoid, sphenoid, and superior maxillary bones. They are 

 narrow transversely, especially above. The internal wall, 

 or septum nasi, is formed by the perpendicular plate of the 

 ethmoid, the vomer, nasal spine of the frontal, crests of the 

 nasal, rostrum of the sphenoid, crests of the maxillary, and 

 palate bones. There is an angular deficiency in front, filled 

 by the septal cartilage, which usually deviates to one side. 



FIG. 12 



OPENING OF POS. 



ETHM. CELLS 

 OPENING OF SPHE- 

 NOIDAL SINUS] 



PENING OF MAX- 

 ILLARY SINUS 



'HARD PALATT 

 The left nasal fossa, viewed from the middle line, showing the three meatuses. (Testul.) 



The roof is horizontal in the middle part and sloping in front 

 and behind. The middle part is formed by the cribriform 

 plate of the ethmoid, the forepart by the nasal and frontal 

 bones, the back part by the body of the sphenoid, the ala 

 of the vomer, and sphenoidal process of the palate. In the 

 angle formed by the cribriform plate and body of the sphenoid 

 is the sphenoethmoidal recess; the sphenoidal sinus opens upon 

 its posterior wall. 



The floor is formed by the palate processes of the maxillary 

 and palate bones; it is smooth and concave transversely, and 

 shows the orifice of the incisor foramen. The external wall 



