HEAD. 77 



brand) of the lower maxillary. Action : Elevates and 

 moves the jaw laterally. 



4. External pterygoideus. — Attachments : Inferi- 

 or face of the sphenoid, subsphenoidal crest, neck of 

 the condyle of the inferior maxillary. Action : Pulls 

 the maxilla forward directly or sideways. 



5. DiGASTRicus. — Synonyms. Stylo-maxillaris, (G). 

 Attachments : Styloid process of the occipital, curved 

 portion of the lower maxilla, internal face of same 

 bone, and straight portion of its posterior border. 

 Action : Fulls the jaw backwards, and at the same 

 time depresses it. 



SPLAIVTMOLOGY. 



IVasal Cavities.^ IS'umber, two. Division : Nostrils, 

 nasal fossa proper and sinuses. 



Nostrils. — Two lips or borders united by two com- 

 missures. The superior commissure shows the false 

 nostrils ; the inferior the opening of the lachrymal duct. 

 Structure: cartilages; muscles, viz: the transversalis nasi, 

 pyramidalis nasi, super-maxillo-nasalis parvus, middle 

 anterior, and supernaso-labialis ; integuments; blood 

 vessels, viz : superior coronary, nasal and palato-labial 

 arteries ; nerves, branches of tlie fifth and seventh 

 cranial pairs. 



Nasal foss^ proper. — Divisions : Four walls and 



