BONES OF THE SKULL. 



esses of the superior maxillae and the horizontal plates of the 

 palate bones. The alveolar processes (superior alveolar arch) 

 of the superior maxillae bound it in front and at the sides; its 

 posterior border presents a mesial (posterior nasal) spine be- 

 tween two thin and free lunated edges. It presents a mesial 

 sagittal (middle palatine) suture in which a pit (anterior pala- 

 tine canal, or fossa) lies just behind the incisor teeth. At the 

 bottom of the pit are two pairs of foramina, one pair (foramina 

 of Stenson) lying side by side, and the other (foramina of 

 Scarpa) lying mesially in front and behind. The suture 

 (transverse palatine) between the superior maxillae and palate 

 bones bends backward on each side to a foramen (posterior 

 palatine canal) just internal to the root of the wisdom tooth; 

 a groove runs forward from this foramen along the inner side 

 of the alveolar arch and may have a sharp inner edge. A 

 transverse ridge lies close to the posterior border. [160] 



The malar bones lie external to the hard palate, on the max- 

 illae, and curve backward (temporal processes) to complete the 

 zygomatic arches. [160] 



The pterygoid processes of the sphenoid lie on either side of 

 the posterior nares, separated from the superior maxillae by 

 the tuberosities of the palate bones ; each tuberosity presents 

 two foramina (posterior, and external accessory, palatine ca- 

 nals) just behind the posterior palatine canal. Each pterygoid 

 process consists of two vertical plates, external and internal, 

 which are separated by a (pterygoid) fossa; the anterior edges 

 of the plates coalesce superiorly but are separated inferiorly 

 by the tuberosity of the palate bone. The posterior free edge 

 of the internal plate ends below in a hook-like (hamular) proc- 

 ess which curves backward and outward; it bifurcates above 

 to enclose a (scaphoid) fossa, whose inner margin ends on the 

 body of the sphenoid in a projection (pterygoid tubercle) which 

 extends backward; just above and external to the tubercle is 

 a foramen (Vidian canal). The internal plate curves inward 

 on the body of the sphenoid, as a lipped edge (vaginal process) 



[11] 



