SKELETAL SYSTEM 



371 



1. The bones of the head. 



2. The bones of the neck and 

 trunk. 



3. The bones of the arms and 

 of the legs together with those of 

 the shoulders and the hips. 



The head. The bones of the 

 skull, except that of the lower 

 jaw, are united firmly together. 

 They are divided into two regions, 

 the cranium, or brain case, and 

 the face. The bones of the cran- 

 ium are large and flat, while those 

 of the face are irregular in shape. 



The trunk. The trunk consists 

 of the following parts: 



1. A main axis, the spinal or 

 vertebral column. . 



2. The ribs. 



3. The breast bone. 



The vertebral column consists of 

 a number of separate bones, called 

 vertebrae, placed one upon another. 

 It is divided into regions as 

 follows : 



1. The cervical, or neck region, consisting of seven 

 vertebrae. 



2. The dorsal region, or region of the back, consist- 

 ing of twelve vertebrae to which the ribs are attached. 



Fig. 170. Side view 

 of spinal column. 



