152 



OSTEOLOGY. 



Orbital process 



Sphenoid 



Sphenoidal process 



Pharyngeal groov 



Middle meatus 



Orbital 

 ^X surface 



Spheno-pala- 

 tine notch 



Crista conchalis 



Inferior meatus 

 Nasal crest 



Posterior 

 nasal 

 spine 

 Ho 



horizontal plate 

 For medial pterygoid lamina 



FIG. 161. THE EIGHT PALATE BONE. 

 As seen from behind. 



Pyramidal 

 process 

 Pterygoid 

 fossa 



where it articulates with the anterior part of the medial pterygoid lamina, expands 

 below into the pyramidal process. The inferior border of the vertical part is con- 

 fluent with the lateral edge of the horizontal 

 part; posteriorly, and immediately in front 

 of the tuberosity, it is notched by the lower 

 extremity of the greater palatine foramen. 

 The superior border supports the orbital 



and sphenoidal processes; the former 



the anterior is separated from the latter 

 by a notch (incisura sphenopalatina), which 

 is converted into the spheno-palatine fora- 

 men by the articulation of the palate bone 

 with the inferior surface of the sphenoid. 

 Through this communication between the 

 pterygo-palatine fossa and nasal cavity pass 

 the spheno-palatine artery and the nasal 

 branches of the spheno-palatine ganglion. 

 The processus pyramidalis (pyra- 

 midal process) is directed backwards and 

 laterally from the angle formed by the 

 perpendicular and horizontal parts, and 

 presents, on its posterior surface, a central 

 smooth vertical groove, bounded on each side by rough articular furrows which 

 unite above in a V-shaped manner with the upper thin posterior edge. These latter 

 articulate with the anterior parts of the lower portions of the medial and lateral ptery- 

 goid laminae, while the central groove fits into the wedge - like interval between the 

 two pterygoid laminae, thus entering into the formation of the pterygoid fossa. The 

 lateral surface of the pyramidal process is rough above, where it is confluent with the 

 lateral surface of the perpendicular part which articulates with the tuberosity of 

 the maxilla ; below, there is a small, smooth, triangular area which appears between 

 the tuberosity of the maxilla and the lateral surface of the lateral pterygoid lamina, 

 and so enters into the medial wall of the infra-temporal fossa. Passing through 

 the pyramidal process in a vertical direction are the foramina palatina minora 

 (lesser palatine foramina) for the transmission of the lesser palatine nerves and 

 vessels. 



The processus orbitalis (orbital process), shaped like a hollow cube, surmounts 

 the anterior part of the vertical plate. The open mouth of the cube is usually directed 

 backwards and medially towards the anterior part of the body of the sphenoid, with the 

 cavity of which it commonly communicates; the anterior part of the cube articulates 

 with the medial end of the angle formed by the orbital plate and infra- temporal 

 surface of the maxilla. Of the- remaining four surfaces, one directed forwards 

 medially articulates with the ethmoid. The others are non-articular : the superior 

 enters into the formation of the floor of the orbit ; the lateral is directed towards 

 the pterygo-palatine fossa ; whilst the inferior, which is confluent with the medial 

 surface of the vertical part, is of variable extent, and overhangs the superior 

 meatus of the nose. 



The processus sphenoidalis (sphenoidal process), much smaller than the 

 orbital, curves up wards, medially, and backwards from the posterior part of the summit 

 of the perpendicular part. Its superior surface, which is grooved, articulates with the 

 anterior part of the inferior surface of the body of the sphenoid and the root of the 

 medial pterygoid lamina, thereby converting the groove into the pharyngeal canal, 

 which transmits an artery of the same name together with a pharyngeal branch 

 from the spheno-palatine ganglion. Its lateral side enters into the formation of part 

 of the medial wall of the pterygo-palatine fossa. Its medial curved aspect is 

 directed towards the nasal cavity, whilst its medial edge is in contact with the ala 

 of the vomer. 



Connexions. The palate bone articulates with its fellow of the opposite side, with the 

 ethmoid, vomer, sphenoid, maxilla, and inferior concha. 



