248 



PHYSIOLOGY AND HEALTH. 



(Fig. XXXIV.) These are placed one upon another, from 

 the pelvis, at the bottom of the back, to the head, on the 

 top of the neck. These bones vary in thickness, from 

 about an inch in the Joins, to about a quarter of an inch in 

 the neck. 



FIG. XXXIV. Vertebra of the JVecfc. 



a, Body of the bone, upper surface. 



b, Ring. 



c, Process of bone extending back- 

 ward. 



d, Front surface of the bone. 



e, e, Processes extending to the right 

 and left. 



596. There are seven of these bones in the neck, called 

 cervical vertebra. These are thin, and have long project- 

 ing or spinous processes extending directly backward, (Fig. 

 XXXIV. c.) There are twelve bones in the back, against the 

 chest. These are called dorsal vertebra. They are con- 



FIG. XXXV. Vertebra of the Back. (Side View.) 



a, Body of- the bone. 



b, c, Processes of bone extending 

 backward. 



nected with the ribs. Their long spinous processes extend 

 downward, (Fig. XXXV. c.) The other five are called lum- 



