THE I' A LATE BOXE 



59 



the soft palate. The inner border is broad, and rough for articulation with its 

 fellow. When the palate bones are in apposition, these Ixjrders fonn a ridge con- 

 tinuing the crest formed by the palatine processes of the maxilla); this crest 

 receives the inferior border of the vomer. The posterior extremity of the crest 

 forms the posterior nasal spine, from which the azygos uvulas arises. 



The vertical plate is thin; of its two surfaces, the outer is rough for articula- 

 tion Avith the maxilla, except a small portion near the middle close to the anterior 

 border where it hjoks into the antrum, and a small triangular surface at the upper 

 end where it forms part of the spheno-maxillary fossa. Towards the posterior 

 border there is a vertical groove, which forms with the maxilla the posterior palatine 

 canal; it transmits the descending jialatine nerves and vessels. The canal may be 

 more or less complete in the palate bone. The internal surface has two transverse 

 ridges separating three shallow depressions. Of these depressions the lower forms 

 part of the inferior meatus of the nose, and the limiting ridge or crest articulates 

 with the inferior turbinal. Above this is the dejiression for part of the middle 

 meatus; the ridge above is for the second turbinal. The upj^er groove is narrower 

 and deeper than the lower two, and forms a large part of the superior meatus. The 

 ridges are known as the turbinated crests. The borders of the vertical plate are 

 terminated by irregular prominences, wliich enter into complex union with sur- 

 rounding bones. 



Fig. 70.— Palate (Left) Boxe. (Inner \ievc.) 



SPHENOIDAL PROCESS 

 SPHENO-PALATINE NOTCH 

 (WHEN THE FORAMEN IS 

 COMPLETE IN THE PALATE 

 BONE, IT IS DUE TO ANKY- 

 LOSIS WITH SPHENOIDAL 

 TURBINAL) 



ORBITAL PROCESS 

 (ETHMOIDAL SURFACE) 



SUPERIOR MEATUS 

 SUPERIOR TURBINATED CREST 



MIDDLE MEATUS 



INFERIOR TURBINATED CREST 

 INFERIOR MEATUS 



The posterior border is vertical, and comes into relation with the anterior 

 border of the internal pterygoid process; below, it terminates in a prominent 

 tuberosity. This presents three grooves or flutes: the inner receives the internal 

 l)terygoid, the outer tlie external pterygoid process, Avhile the middle groove com- 

 pletes the pterygoid fossa, and affords attachment to a few fibres of the internal 

 pterygoid nniscle; X\\e sv per lor constrictor of the pharynx also arises from this process. 

 The tuberosity is tunnelled l)y canals: to the nasal side are the accessory palatine 

 canals ; near its junction Avith the horizontal plate is the orifice of the posterior 

 palatine canal ; and outside this occasionally may be found the nnnute external 

 palatine canals (fig. 81). 



Tlie sphenoidal process, which is a process of variable shape, surmounts the 

 posterior l)ordcr; it has three surfaces and two borders. The superior surface 

 comes into ai)i)osition with the sphenoidal turbinal bone, and forms jjart of the 

 pterygo-palatine canal. The internal surface forms part of the outer wall of the 

 nasal fossa, and is prolonged on to the roof, and comes in contact with the ala of 

 the vomer. The outer surface is subdivided by a thin lip into an anterior smooth 

 portion for the spheno-maxillary fossa, and a posterior rough i)art for the base of 

 the internal pterygoid plate. (If the borders, the posterior is thin and articulates 

 with the internal i)terygoid plate; the anterior border forms the posterior boundary 

 of the spheno-palatine foramen. 



The anterior border of the vertical plate is thin, sharp, and ])resents near the 

 middle the maxillary process, which is received into the maxillary lissure of the 

 maxilla near the lower border of the opening of the antrum. 



