108 THE SKELETON. 



from the zygoma to the masfoid process and extremity of the superior curved line 

 of the occiput. It is formed by the palate processes of the superior maxillary and 

 palate bones, the vomer, the pterygoid processes, under surface of the great wing, 

 spinous processes and part of the body of the sphenoid, the under surface of the 

 squamous, mastoid, and petrous portions of the temporal, and the under surface 

 of the occipital bone. The anterior part of the base of the skull is raised above 

 the level of the rest of this surface (when the skull is turned over for the purpose 

 of examination), surrounded by the alveolar process, which is thicker behind than 

 in front, and excavated by sixteen depressions for lodging the teeth of the upper 

 jaw, the cavities varying in depth and size according to the teeth they contain. 

 Immediately behind the incisor teeth is the anterior palatine fossa. At the bottom 

 of this fossa may usually be seen four apertures : two placed laterally, the foramina 

 of Stenson, which open above, one in the floor of each nostril, and transmit the 

 anterior branch of the posterior palatine vessels, and two in the median line in 

 the intermaxillary suture, the foramina of Scarpa, one in front of the other, the 

 anterior transmitting the left, and the posterior (the larger) the right, naso-palatine 

 nerve. These two latter canals are sometimes wanting, or they may join to form 

 a single one, or one of them may open into one of the lateral canals above referred 

 to. The palatine vault is concave, uneven, perforated by numerous foramina, 

 marked by depressions for the palatine glands, and crossed by a crucial suture, 

 formed by the junction of the four bones of which it is composed. At the front 

 part of this surface a delicate linear suture may frequently be seen, passing outward 

 and forward from the anterior palatine fossa to the interval between the lateral in- 

 cisor and canine teeth, and marking off the pre-inaxillary portion of the bone. At 

 each posterior angle of the hard palate is the posterior palatine foramen, for the 

 transmission of the posterior palatine vessels and large descending palatine nerve ; 

 and running forward and inward from it a groove, for the same vessels and nerve. 

 Behind the posterior palatine foramen is the tuberosity of the palate bone, perforated 

 by one or more accessory posterior palatine canals, and marked by the commence- 

 ment of a ridge, which runs transversely inward, and serves for the attachment of 

 the tendinous expansion of the Tensor palati muscle. Projecting backward from 

 the centre of the posterior border of the hard palate is the posterior nasal spine, 

 for the attachment of the Azygos uvulae muscle. Behind and above the hard palate 

 is the posterior aperture of the nares, divided into two parts by the vomer, bounded 

 above by the body of the sphenoid, below by the horizontal plate of the palate bone, 

 and laterally by the internal pterygoid plate of the sphenoid. Eac_h aperture 

 measures about an inch in the vertical and about half an inch in the transverse 

 direction. At the base of the vomer may be seen the expanded alse of this bone, 

 receiving between them, on each side, the rostrum of the sphenoid. Near the 

 lateral margins of the vomer, at the root of the pterygoid processes, are the 

 pterygo-palatine canals. The pterygoid process, which bounds the posterior 

 nares on each side, presents near its base the pterygoid or Vidian canal, for the 

 V idian nerve and artery. Each process consists of two plates, which bifurcate at 

 the extremity to receive the tuberosity of the palate bone, and are separated behind 

 by the pterygoid fossa, which lodges the Internal pterygoid muscle. The internal 

 plate is long and narrow, presenting on the outer side of its base the scaphoid fossa, 

 for the origin of the Tensor palati muscle, and at its extremity the hamular process 

 around which the tendon of this muscle turns. The external pterygoid plate is 

 bioad forms the inner boundary of the zygomatic fossa, and affords attachment by 

 its outer surface to the External pterygoid muscle 



f SS8e in the middle line is the basilar surfa ce of the occipital 

 e the ** W* ^^ for the attachment of the 

 f the P. ha ^-th depressions on each side for 



1 v J 1 and minor - At the bas * of the 



external pterygoid plate is the foramen ovale, for the transmission of the third 



l e behith- ' emeS 



sal nerve, behind this, the foramen spinosum, which transmits the middle 



