THE SKULL. 65 



line drawn from the third root of the zygoma back to 

 the superior curved line of the occipital. It is exceed- 

 ingly irregular and rough, and is divided into two por- 

 tions, the cranial and the facial. The former occupies 

 the posterior two-thirds and the latter the anterior third 

 of the base. The bones entering into the formation of 

 the inferior surface of the base are, from behind forward, 

 the occipital, two temporal, sphenoid, vomer, two palate, 

 and two superior maxillary ; in all, nine bones. 



About the middle of the cranial portion of the base 

 is the foramen x magnum, the position of which varies 

 somewhat in the different races; as a rule, it is farther 

 posterior in the inferior races than in the higher; in the 

 anthropoid apes it approaches the posterior part of the 

 skull. At each side of the foramen magnum anteriorly 

 are the condyles for articulation with the atlas; behind 

 the condyles are the posterior condyloid foramina, which 

 transmit veins to the lateral sinuses. Passing backward 

 from the foramen magnum to the external occipital pro- 

 tuberance is the occipital crest, from which the inferior 

 curved lines branch outward and downward. At the 

 sides of the crest, between the curved lines, the bone is 

 slightly shallow and rough, for the attachment of mus- 

 cles. In front of the condyles are the large anterior 

 condyloid or hypoglossal foramina, for the transmission 

 of the hypoglossal nerves. These foramina penetrate 

 the bases of the condyles and pass horizontally forward. 

 External to the condyles, and in front of a line drawn 

 from the mastoid process to the anterior portion of the 

 condyle, is the foramen lacerum posteriorus, or jugular 

 foramen. It is irregularly ovoidal in form, the large end 

 of the oval being directed toward the mastoid process ; 

 its axis is directed obliquely outward and backward, 

 forming an angle of from 35 to 45 degrees with the 



