OSTEOLOGY. 13 



bones in front, an inferior surface smooth and showing four inter- 

 vertebral foramina, and a superior surface showing the spinous 

 process and the super sacral foramina. 



THE COCCYX. 



This consists of from fifteen to eighteen segments; the first 

 three or four only are complete, the spinal canal then simply con- 

 tinuing as a groove. The first is often consolidated with the 

 sacrum. 



THE HEAD. 



This consists of eight bones, the occipital, two parietal, two 

 temporal, the ethmoid, frontal and sphenoid. 



OCCIPITAL. 



The occipital forms the upper and posterior portion of the head, 

 and is divided into an external and internal face and circumference. 

 The External Face shows 



The external occipital protuberance, an elevation forming the 

 point of the head. 



The occipital foramen (or foramen magnum) below and in 

 front of the preceding, a large round opening, transmitting the 

 spinal cord, its membranes, the cerebro-spinal vessels and eleventh 

 nerve. 



The basilar process, a long narrow prolongation passing forward 

 to unite with the body of the sphenoid. 



Two sharp crests running outward, the superior, continuing as 

 the zygomatic process, the inferior, terminating at the base of the 

 styloid process. 



The two condyles which lie on either side of the foramen, articu- 

 lating with the atlas. 



The styloid processes, two large blunt projections lying outside 

 the preceding. 



The condyloid foramina, lying at the bottom of a fossa under 

 the condyles and transmitting the twelfth nerves. 



The Internal .Face shows the foramen magnum, condyloid 

 foramen, and a smooth roof for the cranial cavity. 



The Circumference shows 



Articulations above for the parietal bones, and laterally for the 

 temporal. 



