THE INSTEP. 29 



For the same reason it is important to sit square and 

 straight at the table when writing or drawing, and with 

 the shoulders level: otherwise the spinal column may 

 become curved to one side. 



Young children should not be encouraged to walk too 

 early, lest they grow bow-legged, their leg-bones not 

 being stiff enough to bear the weight of the upper part 

 of the body. 



9. Usefulness of the Arch of the Instep. The bones of the 

 foot (Fig. 10) are arranged to make a springy arch which 



Ta 



Cl C ? XT I^^^V BfH 



-JT 



FIG. 10.- The skeleton of the foot. Ca, the heel-bone; C7, C7/, C&, N, some of 

 the tarsal bones; Os, the front end of the metatarsal bones; 7/, the surface which 

 makes the ankle-joint with the tibia and fibula, and bears the weight of the body 

 in standing and walking; Mi, metatarsal bone of the great toe. 



rests on the ground by the heel-bone, Ca, behind, and by 

 the front ends, Os, of the metatarsal bones in front. On 

 the crown of the arch is the surface, Ta, where the foot 

 joins the leg at the ankle-joint. At this joint the weight 

 of the body is borne. The many small bones in the arch 

 glide over one another a little when the crown of the 

 arch is pressed upon; but spring back into place when 

 the pressure is removed. This elastic arch of the foot 



9. Describe the construction of the instep. Why is k arched and 

 elastic ? To what may it be compared ? How may we learn some- 

 thing of the jarring saved us by the instep ? Illustrate the usefulness 

 of a well arched instep in prolonged walking. 



