42 



Nasal Fossa. 



nasal., 

 (p. off. front* 



Corpus oss. 

 sphenoid 



For. 



Hamulu 

 j?terygoi 



52, 



The Nasal Fossa. Cav 



Tlie nasal fossa is divided into the nasal fossa proper, and 

 the sinuses (Sinus frontalis, sphenoidalis, maxillaris). Superiorly the nasal fossa 

 proper is bounded by the nasal bones and the Lamina cribrosa of the 

 ethmoid bone ; inferiorly by the palate process of the superior maxilla and 

 the Partfis horizontals of the palate bones. The lateral walls are formed 

 above by the nasal process of the superior maxilla, the lachrymal bone, 

 the Lamina papyracea of the ethmoid bone 5 further down by the internal 

 or nasal surface of the superior maxilla (Superfic. nasal, max. sup.) the 

 Pars pcrpendicularis of the palate bone, and the pterygoid process of the 

 sphenoid (Proc. ptcryyokl. oss. splimoid.). The anterior wall is formed by 

 the nasal bones; a large part of it is lacking; in its place is the Aper- 

 tura pyriformis. The posterior wall is formed partly by the anterior sur- 

 face of the body of the sphenoid (Corpus oss. sphenoid.), below this are 

 two openings, the Choanae (posterior naresY Each choana is limited above 

 by the body of the sphenoid bone, externally by its pterygoid process 

 (Proc. ptcrijfj. oss. sphenoid.), internally by the vomer and inferiorly by 

 the Pars horizontals of the palate bone. 



