BASE OF THE SKULL. 



61 



foramina ooen, viz., on the posterior wall, the foramen rotundmn, the 

 Vidian canal, and, between the sphenoidal process of the palate bone 

 and the root of the internal pterygoid plate, the pterygo-palatine canal ; 

 on the inner wall, the spheno-palatine foramen formed by the palate bone 

 and a small part of the sphenoidal spongy bone, and opening into the 

 nasal cavity ; and inferiorly, the posterior palatine canal, which leads 

 down to the palate between the palatal and superior maxillary bones. 



The external base of the skull, excluding the lower jaw, is divisible 

 into three parts, anterior, middle, and posterior. 



The anterior division consists of the palate and the alveolar arch. It 

 is traversed longitudinally by a mesial suture, and transversely by that 



Fig. 52. — External Basis 

 OF THE Skull shown 

 IN Figure 49. (A.T.) 4 



Fig. 52 



11 ~i 



1, palatine plate of the 

 superior maxillary bone 

 near the mesial sntiire ; 2, 

 palatine plate of the palate 

 bone below the palato- 

 maxillary suture ; 3, the 

 anterior palatine foramen ; 

 4, is placed outside the 

 posterior palatine foramen, 

 inside the tuberosity of 

 the superior maxilla, and 

 in front of the smaller 

 posterior palatine foramina, 

 in the pyramidal process of 

 the palate bone ; 5, inuei 

 surface of the external 

 pterygoid plate of the 

 sphenoid bone ; 6, is placed 

 within the posterior open- 

 ing of the left nasal fossa 

 on the internal pterygoid 

 plate ; 7, the vomer ; x , 

 the posterior opening of 

 the pterygo-palatine canal 

 in front of the foramen ia- 

 cerum anterius ; 8, spheno- 

 maxillary fissure leading 

 into the orbit ; 9, foramen 

 spinosum ; 10, foramen 

 ovale ; 11, placed on the 

 apex of the petrous bone, 

 between the foramen lace- 

 rum anterius and the in- 

 ferior opieningof the carotid 



canal ; 12, the jugular fossa of the temporal bone, an^l foramen lacerum posterius 

 on the articular eminence of the inner root of the zygoma ; 14, meatus auditorius externus ; 

 15, glenoid fossa in front of the fissure of Glaser ; 16, tympanic jilate or posterior part of 

 the glenoid fossa, close to the styloid process, below which is seen the stylo-mastoid fora- 

 men ; 17, mastoid x>rocess, and to its inside the digastric and occipital grooves ; j 8, 

 basilar process of the occipital bone, and in front the mark of the still incomplete union 

 with the body of the sphenoid bone ; 19, condyle of the occipital bone ; 20, is placed in 

 the foramen magnum, and points to the lower opening of the anterior condylar foramen ; 

 21, posterior condylar foramen ; 22, jugular process of the occipital bone, and to its inner 

 side the jugular notch ; 23, external occipital spine running down from the protuberance : 

 24, superior curved line of the occipital bone ; 25, inferior curved line ; 26, groove and 

 ridge of insertion of obliquus capitis superior muscle. 



13, 



