THE SKELETON. 37 



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 posterior nares and the cranial part of the 

 walls of the median pterygoid fossa, and a portion of the 

 nasal wall of the orbital cavity ; the other, horizontal, form- 

 ing part of the roof of the mouth. The vertical plate 

 is pierced by two foramina, the posterior palatine and the 

 spheno palatine, each of which transmits a palatine nerve 

 and artery (Fig. 16). 



The vomer is a single narrow bone which in the nasal 

 cavity articulates dorsally with the mesethmoid and ven- 

 trally with the palatines and the palatine plates of the 

 maxillary, in the median line. This bone, with the mes- 

 ethmoid 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 presphe- 

 noid to its articulation with the premaxillaries. The caudal 

 portion of the bone is expanded horizontally and articu- 

 lates with the ventral ethmoturbinals. Its dorsal margin 

 is bifurcated for articulation with the mesethmoid. 



The maxilloturbinal is a paired bone occupying the an- 

 terior portion of the nasal cavity (Fig. 18). It is composed 

 of a few scrolls which, when the nasal bone is removed, 

 may be seen attached to the maxillary. It consists of a 

 horizontal longitudinal plate, whose lateral border is fixed 

 to the maxillary while the medial border bifurcates into a 



