14 



STRUCTURE OF THE HUMAN BODY 



head to turn from side to side, that is to rotate, a pivot 

 projects upward from the second vertebra into a ring 

 on the first vertebra. 



Of the back. In the upper part of the trunk, or 

 dorsal region, on the contrary, stability rather than 



Surface on which skull rests 

 Odontoid process of axis 

 .Transverse process 

 Vertebral artery 



Neural arch 



Ligament 



Neural canal (for spinal cord) 

 Spinous process 



The Atlas 



Odontoid process 



(pivot for atlas) 



Articular surface for atlas 

 Vertebral artery 



The Axis 



FIG. 10. The relation between the 1st and 2nd vertebrae, permitting rotation of 

 the head. 



freedom of movement is required, in order that the ribs 

 which are attached to the vertebras may receive ade- 

 quate support. The vertebrae of the back are therefore 

 firmly united by additional ligaments and bony exten- 

 sions or processes, in order that any considerable move- 

 ment of the vertebrae may be checked. In childhood, the 



