THE PALATE BONE. 



47 



part of the floor of the nasal cavity ; its inferior surface is rough, and is 

 marked near its posterior border by a transverse ridge passing inwards from 

 the base of the pyramidal process, giving attachment to the tendinous fibres 

 of the tensor palati muscle. 



Fig. 40. 



Fi gt 40. THE PALATE BONE OF THE RIGHT SIDE, f 

 A, from the outside and behind ; B, from the inside. 

 1, the upper surface of the palatine plate; 2, its 

 posterior curved border or palatine arch ; 3, posterior 

 nasal or palatine spine ; 4, the rough surface of adjacent 

 articulation rising superiorly into the vomeric crest, as in 

 A ; 5 5, the nasal process ; 6, the ridge or shelf support- 

 ing the inferior turbinated bone ; 7, the sphenoidal 

 process ; 8, in B, the orbital process, showing a cellular 

 cavity ; 8', in A, its orbital surface ; 9, the spheno- 

 palatine notch ; 10, 11, 12, the pyramidal process 10, 

 rough surface of union with the external pterygoid plate, 

 11, with the internal ditto, and 12, the inter-pterygoid 

 smooth surface; 13 13, pala to-maxillary or posterior 

 palatine canal. 



The vertical plate is very thin. Its internal 

 surface looks towards the nasal cavity, and is 

 divided into two parts, corresponding to the 

 middle and inferior meatus of the nose by a 

 nearly horizontal ridge which articulates with 

 the inferior turbinated bone. The external 

 surface is traversed by a smooth impression, 

 directed downwards and slightly forwards, the 

 upper part of which forms the internal wall 

 of the spheno-maxillary fossa, while the lower 



part is hollowed into a deep groove, completing with the superior maxil- 

 lary the posterior palatine canal, which transmits the large descending 

 palatine nerve and accompanying vessels. In front of this canal the 

 external surface is in contact with the internal surface of the maxillary 

 bone and the side of the antrum ;, behind the canal it articulates inferiorly 

 with the hinder border of the maxillary, superiorly with the inner surface of 

 the pterygoid process. 



The pyramidal process or tuberosity fits into the cleft between the ptery- 

 goid plates. It presents posteriorly a triangular surface which is smooth 

 and grooved, and completes the pterygoid fossa ; on its sides it is rough for 

 articulation with the borders of the pterygoid plates. Inferiorly, close to 

 its connection with the horizontal plate, are two small foramina, the posterior 

 and external small palatine foramina, the extremities of two minute canals 

 which transmit the smaller palatine nerves ; the external one is the smaller 

 and is inconstant. 



The orbital process surmounts the anterior margin of the vertical plate. 

 It has the general appearance of an inverted pyramid, and has five surfaces, 

 two of which, the superior and external, are free, and the rest articulated. 

 The superior surface forms the posterior angle of the floor of the orbit ; the 

 external looks into the spheno-maxillary fossa, the anterior articulates with 

 the maxillary, the internal with the ethmoid, and the posterior, which is 

 small and only exists towards the extremity of the process, articulates with 

 the sphenoidal spongy bone. 



The orbital surface is frequently found enlarged, extending upwards between the 



