38 BONES, JOINTS, AND LIGAMENTS 



Dislocation. When the bones forming a joint are put 

 under such severe strain that they are pried or pulled 

 out of place, the joint is said to be dislocated. In the 

 case of most joints, dislocation is accompanied by more 

 or less tearing of the capsular ligaments, and at times 

 even by injury to the ends of the bones. 



Bone-building materials. The earthy material for 

 the building of bones is present in all food in small but 

 sufficient quantities for normal growth and constitutes 

 a portion of the ash which remains when food is burned. 

 Although all foods contain a certain amount of bone- 

 building material, some contain more than others. 1 It 

 is therefore of the greatest importance, especially dur- 

 ing such a period of rapid growth as early childhood, 

 to have food which will give the bones proper nour- 

 ishment. Although pure milk, for example, is a suffi- 

 cient food for infants, yet when the child at the age 

 of from eight to ten months becomes active and sup- 

 ports his weight by his bones in sitting, standing and 

 walking, milk should be supplemented by cereals and 

 fruit juices. If this is not done, the bones are frequently 

 so poorly built that they bend under the weight of the 

 child and he becomes bow-legged, knock-kneed, or flat- 

 footed, and may even have deformed arms and a crooked 

 back. 2 Plenty of wholesome food, fresh air and sunshine 



this complication is overlooked, as frequently happens, the serious- 

 ness of the sprain is greatly aggravated. 



1 See table of food materials, p. 86. 



3 A similar condition of weakness of bones arises even more 

 frequently when the food of babies is limited to certain infant 

 foods which are largely modified starch and so fail to give the 

 other constituents of a complete diet. Many parents are deceived 

 by the resulting fatness of the baby and do not realize that a child 

 may be fat and yet be weak, because it is being deprived of neces- 

 sary food constituents. The excess of fat is even a great disad- 

 vantage, because it overburdens weak bones, which normally are 

 none too strong in a child who is just beginning to walk. 



