140 THE PRINCIPLES OF MYODYNAMICS. 



teen) by five and it gives the entire force of the 

 psoas magnus, which equals eighty-five pounds. 

 And this means that the femoral head is pressed 

 against the acetabular surface by the psoas mag- 

 nus with a force equal eighty-five pounds : — 

 Now, suppose the weight of the lower limb to 

 be twelve pounds, and the weight of the body 

 to be sixty pounds : and if the psoas magnus 

 lifts the weight of the lower limb applied to the 

 condyloid end of the femoral lever, it will press 

 the hip-joint surfaces together with a force of 

 eighty-five pounds : But if the w^eight of the 

 body rests on one limb, it will press the hip- 

 joint surfaces together with a force of only sixty 

 pounds. The psoas magnus can do, under the 

 circumstances, more work than the weight of 

 the body. 



140. Let the weight on the condyloid end of 

 the femoral lever be twenty-four pounds : — 

 Then the force of the proas magnus will be 1 70 

 pounds. — Let the entire force of the rest of the 

 muscles that span the hip-joint be ten times as 

 great as the force of the psoas magnus, then the 



