34 OUR BODIES AND HOW WE LIVE 



The large bone, which projects backwards, is the heel bone. 

 It is connected with the great calf muscles of the leg by a 

 very strong cord, or tendon, called the tendon of Achilles. 1 



The five metatarsal, or instep bones correspond to the 

 palm bones of the hand. 



The phalanges are the fourteen bones of the toes. 



55. Why the Foot is built in the Form of an Arch. The 

 foot is built in the form of a half dome or half arch. This 

 is to afford a broad, strong surface for the support of the 

 weight of the body. The bones of the toes and the heel 



FIG. 26. The Bones of the Foot. 



form the piers, while the little bones wedged in between 

 the metatarsal bones and the heel make up the keystone of 

 the arch. This arch gives a certain amount of spring and 

 elasticity to the feet, and hence it is of the utmost impor- 

 tance in preventing jars and jolts. 



Experiment 11. Place your bare foot in water and then stand on 

 a dry board. The imprint on the board will show you how much of 

 the foot touches the ground, and thus the extent of the arch. 



56. How Bones are joined together. The place where 

 two bones join together is called a joint or an articulation. 



Joints vary according to the kind and amount of motion. 

 In all joints the essential parts are the same. 



1 The warlike deeds of this famous Greek hero were sung by Homer. 

 According to the story, Achilles received his death wound in the heel, no 

 other part of his body being vulnerable. 



