BONES, MUSCLES, EXERCISE, AND REST. 255 



(Fig. XLU.) This gives to all the bones freedom of motion, 

 and to the whole foot its greatest elasticity. But the shoes 

 that are usually worn are narrowed in front of the ball of 

 the foot, and the toes are rounded, and even pointed some- 

 times. This shape carries the toes inward from both sides, 



FIG.- XLII. FIG. XLIII. 



Natural shaped Foot. Compressed Foot. 



and causes some of them to override others, (Fig. XLIII.) 

 This diminishes the freedom of motion, the elasticity of 

 action, and the usefulness of the feet, and creates a limping 

 and awkward gait. 



CHAPTER IV. 



Joints. Hinge. Elbow. Knee. Ball and Socket. Shoulder. 

 Hip. Cartilages. Self-oiling Apparatus. Ligaments. Cap- 

 sules. Sprains. Dislocations. 



606. The joints unite the bones together, and yet allow 

 them to play upon each other. They are so strong that the 

 bones cannot be separated without great violence, yet they do 

 not interfere with their motions upon each other. There are 

 various kinds of these joints, suited to the wants of the several 

 parts in which they are placed. 



The hinge joint allows motion in only one direction, for- 



