116 THE CANCELL1 OF BONES 



phoid bone. In the angle formed by these two 

 series is a third (c), much less regular, the direc- 

 tion of which is not well defined, but has a gen- 

 eral tendency downwards and forwards towards 



FIG. 32. 



the anterior and inferior articulating surfaces of 

 the bone. This portion sustains no direct pres- 

 sure. 



v. os CALCIS 



It is through this bone that the weight is at 

 last transmitted to the ground, and this takes 

 place in two different directions : one directly 

 through the tuberosity of the heel, and the other 

 indirectly through that surface which articulates 

 with the cuboid bone, and this in turn with the 

 4th and 5th toes. The os calcis, how r ever, does 

 not simply form a basis of support ; it is at the 

 same time one of the arms of a lever by which 

 the body is raised from the ground under the 

 influence of great muscular action. The whole 



