86 OSSA MAXILLARIA SUPERIORA. 



Ossa Maocillaria Superiora. 



The ossa maxillaria superiora, or upper jaw bones, may be 

 considered as the basis or foundation of the face ; as they form 

 a large part of the mouth, the nose, and the orbit of the eye. 



The central part of each bone, which may be considered as 

 its body, is hollow, and capable of containing, in the adult, 

 near half an ounce of fluid. . The plate which covers this 

 cavity is the bottom of the orbit of the eye. The sockets of 

 the large teeth are below it. The roof of the mouth projects 

 laterally from the inside of it. A process for supporting the 

 cheek bone is on the outside ; and another process goes up 

 before it, which forms the side of the nose. 



Fig. 20.* In each upper maxillary bone the fol- 



lowing parts are to be examined : 



The nasal process ; the orbitar plate ; 

 the malar process ; the alveolar process ; 

 the palatine process ; the anterior and 

 posterior surfaces ; the great cavity ; the 

 internal or nasal surface ; and the three 

 foramina. 



The nasal process, which extends 

 upwards to form the side of the nose, 

 is rather convex outwards, to give the 

 nostril shape. Its sides above support 

 the nasal bone ; and a cartilage of the 

 alae nasi is fixed to its edge below. 



The margin of the orbit of the eye is marked by a sharp 

 ridge on the external surface of this process ; and the part 



* The superior maxillary bone of the right side, as seen from the lateral 

 aspect. 1. The external, or facial surface ; the depression in which the figure 

 is placed is the canine fossa. 2. The posterior, or zygomatic surface. 3. The 

 superior, or orbital plate or surface. 4. The infra-orbital foramen : it is situated 

 immediately below the number. 5. The infra-orbital canal, leading to the infra- 

 orbital foramen. 6. The inferior border of the orbit. 7. The malar process. 

 8. The nasal process. 9. The concavity forming the lateral boundary of the 

 anterior nares. 10. The nasal spine. 11. The incisive, or myrtiform fossa. 

 12. The alveolar process. 13. The internal border of the orbital surface, which 

 articulates with the ethmoid and palate bones. 14. The concavity which articu- 

 lates with the lachrymal bone, and forms the commencement of the nasal duct. 

 15. The palate process, t. The two incisor teeth, c. The canine, b. The two 

 bicuspidati. m. The three molares. 



