OF THE ATTITUDES AND OF LOCOMOTION. 



139 



regions: the tarsus, metatarsus, and toes. In the tarsus 

 there are seven bones, the astragalus, os calcis, scaphoid, 

 cuboid, and three cuneiform bones ; in the metatarsus there 

 are five bones, reckoned numerically, from the inner to the 

 outer side of the foot ; and in the region of the toes, there 

 are for the great toe, two phalanges, and for the others three ; 

 besides these, as in the hand, there are two sesamoid bones, 

 constant and regular, developed in the tendon of the short 

 flexor below the ball of the great toe. 



In man the great toe cannot be opposed to the others ; the 

 second toe is the longest in all well -formed feet. The tarsal 

 and metatarsal bones form a strong arch towards the inner 

 and lower surface of the feet, protecting the vessels, nerves, 

 and tendons passing from the foot to the leg, and the opposite. 

 The short flexors of the toes are placed in the sole of the foot ; 

 the tendo- Achilles, the strong tendon through which 'the 

 extensor muscles act on the foot in walking, is attached to 

 the tuberosity of the calcaneum. The size of the peroneal 

 muscles is a peculiarity in the human leg. 



Of the Attitudes and of Locomotion. 



283. All mammals, birds, reptiles, and fishes, have a 

 skeleton formed on the same plan as in man. It gives to the 

 body its general form, regulates its development and movements. 



284. Station or Standing. With the exception of 

 serpents, most animals rest on the soil by means of limbs or 

 extremities. They 

 stand by means of 

 the action of the ex- 

 tensor muscles; and 

 thus standing for a 

 long time erect be- 

 comes more fatiguing 

 than walking, for 

 in this the flexors 

 and extensors are 

 used alternately. 



285. But the 

 body must also be Fig. 84. 



in equilibria, or 



balanced on its base of sustentation ; and the point around 

 which all its movements are performed is called the centre of 

 gravity. Now, to support the centre of gravity, it is necessary 



