REGIONS OF THE SKULL. 119 



above this ridge, and the muscles from the sternum and 



scapula below it. 



The internal or posterior surface of the body is very concave. 

 The cornua, in young subjects, are distinct from the 7 body 



of the bone, and joined to it by cartilages : near the body of 



the os hyoides they are flat ; but their figure soon changes, and 



they terminate on each side in a small tubercle. 



Fig. .21.* On the upper edge of the bone, 



where the cornua unite to the body, 

 is a process, equal in size to a small 

 grain of wheat, which has a direction 

 upwards and backwards ; this is 

 called the appendix, or lesser cornu 

 of the os hyoides : from it proceeds 



a ligament which is attached to the styloid process of the 



temporal bone, and is sometimes ossified. 



The basis of the tongue is attached to the os hyoides, and 



the motions of the bone have a particular reference to those of 



that organ ; but they will be better understood when the parts 



with which it is connected have been described. 



Regions of the Skull. 



The skull considered as a whole may be divided for the 

 occasional purpose of defining the seats of injuries into four 

 regions. 



The superior region or vertex, is bounded anteriorly by the 

 frontal eminences ; on each side by the temporal ridges and 

 parietal eminences, and behind by the superior curved line of 

 the occipital bone and occipital protuberance. The anterior 

 region or face as seen in Fig. 28, is somewhat oval in contour, 

 irregular in surface and excavated for the reception of two 

 principal organs of sense, the eye and the nose. It is formed in 

 part by the frontal bones and by the bones of the face. It is 

 bounded above by the frontal protuberances, below by the 



* The os hyoides seen from before. 1. The anterior convex side of the body. 

 2. The great cornu of the left side. 3. The lesser cornu of the same side. The 

 cornua were ossified to the body of the bone in the specimen from which the 

 figure was drawn. 



