I20 THE PRINCIPLES OF MYODYXAMICS. 



angle, the force of the quadriceps must increase 

 as well as the mutual pressure of the ends of the 

 bones ; and these facts take place in the order 

 indicated during flexion of the leg. The patella 

 augments the myodynamic angle : Hence the 

 patella makes the quadriceps act to greater 

 advantage, and relatively diminishes the mutual 

 pressure of the ends of the bones. 



111. These conclusions may be demonstrated 

 substantially by the following experimental 

 means : Take the bones of the lower limb, as 

 the)- are articulated in a skeleton, and fasten a 

 dynamometer to the upper end of the patella by 

 means of a string- : when the leg^ is extended, 

 the dynamometer will have its index at a certain 

 figure, and as the leg is constantly flexed by 

 means of its own weight, the index of the dy- 

 namometer will as constantly point to a greater 

 fieure. 



o 



112. When the leg is completely extended, 

 the semi-membranosus has a larger moving com- 

 ponent than the semi-tendinosus, because it acts 

 on a longer power-arm: See P' s-m, Fig. 24. 

 But when the tibia meets the femur at a right 



