THE BONES OF THE HEAD 147 



palatine artery from the palate to the nasal fossa, whilst each of 

 the latter transmits the naso-palatine nerve from the nasal fossa 

 to the hard palate, the anterior, which usually opens from the left 

 nasal fossa, containing the left nerve, and the posterior, which 

 usually opens from the right nasal fossa, containing the right 

 nerve." Internal to the last molar alveolus at either side is the 

 posterior palatine foramen, which is the outlet of the posterior 

 palatine or palato-maxillary canal, and through which the great 

 or anterior descending palatine nerve and the descending palatine 

 vessels pass. Leading forwards from this foramen there is a groove 

 for the transmitted structures. A little behind the posterior 

 palatine foramen is the posterior accessory palatine foramen for 

 the posterior de cending palatine nerve, and outside this is the 

 external accessory palatine foramen for the external descending 

 palatine nerve, but the last-named foramen is inconstant. Besides 

 the foregoing openings, there are a number of nutrient foramina. 

 Over its anterior three-fourths the hard palate presents several 

 depressions for the palatal mucous glands, and extending inwards 

 from the back part of the posterior palatine foramen at either 

 side is a transverse ridge which gives partial insertion to the tensor 

 palati muscle. 



The middle division extends from the posterior border of the 

 hard palate to a transverse line on a level with the anterior margin 

 of the foramen magnum. Laterally it is limited by a line extending 

 from the tuberosity of the superior maxilla to the styloid process 

 of the temporal. It is on a higher level than the anterior division, 

 and its central or basilar part is known as the guttural fossa. 

 The bones forming it at either side are the tuberosity of the 

 palate bone, the pterygoid process, and a small part of the 

 great wing, of the sphenoid, and the inferior surface of the petrous 

 portion of the temporal. The central part is formed by the 

 basilar process of the occipital, the body and vaginal processes 

 of the sphenoid, the superior border and alae of the vomer, and 

 the sphenoidal processes of the palate bones. 



Anteriorly it presents the posterior nares, already described, and 

 at either side of these openings is the pterygoid fossa, which is 

 bounded internally by the internal, and externally by the external, 

 pterygoid plate of the sphenoid, the fossa being completed in- 

 feriorly by the tuberosity of the palate bone. 



In a line extending backwards and outwards from the extemcd 

 pterygoid plate to the styloid process the following parts are 

 seen, in order from before backwards : foramen ovale ; foramen 

 spinosum ; spinous process of the sphenoid ; internal border 

 of the tympanic plate of the temporal, forming posteriorly the 

 vaginal process ; and styloid process. Inside the foregoing line 

 anteriorly is the Eustachian groove, which lies obliquely between 

 the great wing of the sphenoid and the apical part of the petrous 

 portion of the temporal. This groove lodges the cartilaginous part 



