THE FACE 



327 



The posterior and shortest ridge is directed backward and upward 

 from the posterior part of the rim of the spheno-palatine foramen ; it 

 joins the last partition on the external surface of the lateral ethmoid, 

 and divides the ethmoidal process from a triangular area on the inner 

 surface of a small almost vertical part of the sphenoidal process which 

 overlaps the side of the orbitosphenoid. 



The second ridge begins at the anterior end of the spheno-palatine 

 foramen and passes to the superior border parallel with the first ; it 

 joins the penultimate partition of the lateral ethmoid. 



FIG. 255. 



Interprem ayillary Sutu re. 



Rignt Premaxillary 



* [ Palatint Process. 



Eight Maxil- 

 lary 



Ethmoidal PruccM) 

 of Right Palatine, > 

 Nasal Surface. ) 



Right 

 tine 



Sphenoidal Process of Right 



T'omer, im'M Maxillaries. 

 Left Lateral Ethmoid. 







Left Lower Ethmoidal 

 Scrott. 



'omer. 



Presphenoid. J '' 



- Left Pterygoid. 



NASAL FOSS.E FROM BELOW. 



Palatine Processes of Maxillaries and Palatines removed. Left side of posterior part 



of Vomer cut away. 



The third or anterior ridge begins with the second, but runs almost 

 vertically ; it joins the posterior edge of the plate which forms the 

 posterior margin of the ethmoidal cleft. The triangular area in front 

 of this ridge is often deeply concave and forms with the side of the 

 ethmoidal plate the posterior part of a well-marked nasal fossa, which 

 corresponds to the human maxillary sinus. The curved ridge which 



