186 



SKELETON AND MUSCLES 



certain amount of bone has taken the place of this soft 

 cartilage. 



When the bone of a limb is broken the physician sets it, 

 Le. places the broken ends together, and puts splints on 

 the limb to keep the parts from slipping until the new bone 

 has formed and hardened. 



The joints of the bones of the arms and legs allow move- 

 ments in many directions. The tearing or stretching of 



Figure 196. — X-ray of 

 Hand of Child. 



Figure 197. — X-ray of Hand of Adult. 



the structures which hold the bones together at the joints 

 is called a sprain. The joints in the spinal column allow 

 only a limited movement, while the joints in the cranium 

 are immovable and some of its bones gradually grow 

 together. 



The erect position of man gives to his skeleton important 

 characteristics which the skeletons of other animals do 



