THE SKELETON 49 



The maxillary is a paired bone which meets its fellow in the 

 median line in the roof of the mouth. All its articulations are 

 visible externally except those with the maxillo-turbinal, eth- 

 moid, and vomer. Five teeth, a canine, three premolars, and a 

 molar, are present in this bone of the adult cat. The molar is 

 wanting to the young. The several portions of the bone are as 

 follows: the palatine plate, appearing in the roof of the mouth; 

 the nasal process, extending dorso-caudad to the frontal; the 

 process, extending ventrad to the orbit to articulate with the 

 malar bone; and the orbital plate, which is the roof of the malar 

 process, forming a partial floor to the orbital cavity. The large 

 foramen leading from the orbital cavity through the orbital plate 

 is the infraorbital foramen for the passage of the infraorbital 

 branch of the superior maxillary branch of the fifth nerve. 



The palatine bone with its fellow helps to form the roof of the 

 oral cavity and the floor of the nasal cavity. It is composed 

 of two plates: one, vertical, forming the lateral walls of the pos- 

 terior nares and the cranial part of the walls of the median ptery- 

 goid fossa, and a portion of the nasal wall of the orbital cavity; 

 the other, horizontal, forming part of the roof of the mouth. 

 The vertical plate is pierced by two foramina the posterior 

 palatine and the sphenopalatine, each of which transmits a 

 palatine nerve and artery (Fig. 17). 



The vomer is a single narrow bone which in the nasal cavity 

 articulates dorsally with the mesethmoid and ventrally with 

 the palatines and the palatine plates of the maxfllary, in the 

 median line. This bone, with the mesethmoid and its cartilage, 

 forms the nasal septum, dividing the nasal cavity into two 

 chambers. It is best demonstrated by removing the palatines, 

 when it may be seen extending craniad from its bifurcated 

 articulation with the presphenoid to its articulation with the 

 premaxillaries. The caudal portion of the bone is expanded 

 horizontally and articulates with the ventral ethmoturbinals. 

 Its dorsal margin is bifurcated for articulation with the 

 mesethmoid. 



