OS OCCIPITIS. 



boundary of the foramen lacerum anterius of the base of the 

 cranium. The posterior angle separating the posterior from the 

 basilar surface of the bone, is grooved for the inferior petrous 

 sinus and excavated for the jugular fossa : it forms the anterior 

 boundary of the foramen lacerum posterius. 



The temporal is articulated with the parietal, occipital and 

 sphenoidal bones, and by its zygomatic process with the malar 

 bone. 



Os Occipitis. 



The occipital bone is situated at the posterior and inferior part 



of the cranium ; it is of a rhomboidal figure, with convex and 



concave surfaces. 



Fig. 16.* The upper part of the 



external surface is smooth : at 

 a small distance above the 

 middle of the bone is the 

 external occipital protube- 

 rance, with a curved line on 

 each side of it. Near the 

 middle of the bone the tra- 

 pezii muscles are attached to 

 this line, and externally, on 

 each side, the occipito fron- 

 talis, and the sterno mas- 

 toideus. Under this line is a 

 depression, on each side, into 



which are inserted the complexus and the splenius capitis 



muscles. 



Below this is the inferior curved line, and still lower is a 



* The external surface of the occipital bone. 1. The superior curved line. 

 2. The external occipital protuberance. 3. The spine or vertical ridge. 4. The 

 inferior curved line. 5. The foramen magnum. 6. The condyls of the right 

 side. 7. The posterior condyloid fossa, in which the posterior condyloid foramen 

 is found. 8. The anterior condyloid foramen, concealed by the margin of the 

 condyle. 9. The jugular eminence or transverse process as it is sometimes 

 called. 10. The notch in front of the jugular eminence, which forms part of 

 the jugular foramen. 11. The basilar process. 12. The rough projections into 

 which the moderator ligaments are inserted. 



