Il8 THE PRINCIPLES OF MYODYNAMICS. 



no. If now the weight of the body be put on 

 the tibia as a lever, the tibia will have the same 

 dynamic relation to the femur as the foot has to 

 the bones of the leg, and the tibia will be a lever 

 of the second order. 



(i.) In case the body is erect, and on the 

 supposition that there is no action of the muscles 

 that span the knee-joint, the weight of the body 

 minus the weight of the legs will rest on the 

 bases of the tibiae ; and the muscular force re- 

 quired to maintain the body erect at the knees 

 must be added to this weight. 



(2.) Let the body weigh i5o pounds, and let 

 it rest on the tibial levers meeting the femora 

 at right angles : The pressure on the joint- 

 surfaces would be over 1200 pounds : on two 

 condyles the pressure would be 600 pounds : 

 and on one condyle the pressure would be 300 

 pounds. — But, if the weight of the body rested 

 on one leg, the pressure on two condyles would 

 be 1 200 pounds ; and the pressure on one con- 

 dyle would be 600 pounds. 



(3.) It appears that, as the myodynamic angle 

 C P D decreases or becomes less than a right 



