OCCIPITAL BONE. 



21 



OF THE SKULL. 



The skull, or superior expansion of the vertebral column, is divisible 

 into two parts, the cranium and the face ; the former being adapted 

 by its form, structure, and strength, to contain and protect the brain, 

 and the latter the chief organs of sense. 



The CRANIUM is composed of eight separate bones ; viz. the 

 Occipital, Two temporal. 



Two parietal, Sphenoid, 



Frontal, Ethmoid. 



OCCIPITAL BONE. This bone is situated at the posterior part and 

 Fig. 11.* 



base of the cranium. It is trapezoid in figure, and divisible into two 

 surfaces, four borders, and four angles. 



External Surface. Crossing the middle of the bone transversely, 

 from one lateral angle to the other, is a prominent ridge, the superior 



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

 2. The external occipital protuberance. 3. The spine. 4. The inferior curved 

 line. 5. The foramen magnum. 6. The condyle 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 transverse process ; this process upon the internal surface of the bone 

 forms the jugular eminence. 10. The notch in front of the jugular eminence 

 which forms part of the jugular foramen. 11. The basilar process. 12, 12. 

 The rough projections into which the odontoid ligaments are inserted. 



