THE PRINCIPLES OF MYODYNAMICS. lOI 



the displacement will occur at the ankle-joint, 

 complicating a dislocation with a fracture. 



98. In this place, it is proper to determine 

 whether or not the foot acted on by the muscles 

 of the tendo Achillis is a lever of the second order. 

 Under the circumstances, it has already been 

 shown by transposing terms that the foot in- 

 volves the principles of a lever of the first order. 

 This would be true of any lever of the second 

 order. In a lever of the second order, the 

 weight is somewhere in the continuity of the lever, 

 the power is at one end, and the fulcrum is at 

 the other end of the lever. The body is cer- 

 tainly the weight to be moved, and it rests on the 

 continuity of the lever : The muscles of the 

 tendo-Achillis act on one end of the lever — this 

 is the power ; the other end of the lever rests 

 on some resisting surface — and this is the ful- 

 crum. Here we have all the conditions of a 

 lever of the second order. Hence, we conclude 

 that the foot is a lever of the second order. But 

 the weight to be moved — that is, the weight of 

 the entire body — is only part of the entire force 



