92 



THE SKELETON 



a vertical groove which forms with the maxilla the pterygo -palatine canal for 

 the transmission of the anterior palatine nerve and the descending palatine 

 artery. The part of the surface in front of the groove articulates with the nasal 

 siuface of the maxilla and overlaps the orifice of the antrum by the maxillary 

 process, a variable projection on the anterior border. Behind the groove the 

 surface is rough for articulation with the maxilla below and the medial pterygoid 

 plate above. 



Fig. 115. — Palate Bone (Left). (Medial view.) 



Sphenoidal process 



Spheno-palatine notch (when the 

 foramen is complete in the palate 

 bone, it is due to ankylosis with 

 sphenoidal concha) 



Orbital process (ethmoidal surface) 



Superior meatus 

 Ethmoidal crest 



Middle meatus 



Conchal crest 

 Inferior meatus 



The medial or nasal surface presents two nearly horizontal ridges separating 

 three shallow depressions. Of the depressions, the lower forms part of the inferior 

 meatus of the nose, and the limiting ridge or conchal (inferior turbinate) crest 

 articulates with the inferior nasal concha. Above this is the depression forming 

 part of the middle meatus, and the ridge or ethmoidal (superior turbinate) crest, 

 constituting its upper boundary, articulates with the middle nasal concha. 



Fig. 116. — Palate Bone. (Posterior view.) 



Orbital surface _ 



Zygomatic surface 



Spheno-palatine foramen (usually a 

 notch) 



Groove for external pterygoid 



Groove for pterygoid fossa 

 Groove for internal pterygoid 



Tuberosity 



Orbital process 



Sphenoidal process 



Spine of palate 



The upper groove is narrower and deeper than the other two and forms a large part of the 

 superior iiKJiitu.s of the nose. The anterior border of the vertical plate is thin and bears the 

 maxillary process, a tongue-like piece of bone, which extends over the opening of the maxillary 

 sinu.s from behind. This border is continuous above with the orbital process. The posterior 

 border is rough and articulates with the anterior border of the medial pterygoid plate. It is 

 continuous sui)eriorly with the sphenoidal process. 



The pyramidal process or tuberosity fits into the notch between the lower extremities of 

 the pterygoid plates and presents posteriorly tlu'ce grooves. The middle, smooth and concave, 

 completes the pterygoid fossa, and gives origin to a few fibres of the irUernal pterygoid; the 

 medial and lateral grooves are rough for articulation with the anterior border of the correspond- 

 ing j)ti'rygoid plate, iiiferiorjy, close to its junction with the horizontal plate, are the openings 

 of the greater palatine and smaller palatine canals, of which tiie latter are the smaller and less 

 constant; they transmit the palatine nerves. Meclially the ])yramidul ])roccss gives origin to a 

 few fibres of the nupcrinr conslridor of the pharynx, and laterally a small part appears in the 

 zygomatic fossa between the tuberosity of the maxilla and the pterygoid process of the sphenoid. 



The sphenoidal process, the smaller of the two processes surmounting the vertical part, 

 curves upward and nir'(iially and presents three surfaces and two borders. The superior sur- 

 face is in contact with 1 ho body of the sphenoid, and the top of the medial pterygoid plate, where 

 it completes the pharyngeal canal. The medial or inferior surface forms part of the lateral 



