THE PRINCIPLES OF MYODYNAMICS. 46 



dition of maximum stability, when the myody- 

 namic angle is a right angle, in the case of any 

 bony lever. But the stability of the joint be- 

 comes relatively less as the myodynamic angle 

 differs from a right angle, in the case of any 

 bony lever. The displacing component is a 

 factor of instability, and is antagonized by the 

 capsular ligaments. 



29. B. In the case of any order of bony 

 lever, the following general conclusions may be 

 drawn : — 



(i.) When the myodynamic angle is acute a 

 greater part of the force of the contracting muscle 

 will be a displacing component than when this 

 angle is obtuse. 



(2.) When the myodynamic angle is obtuse a 

 greater part of the force of the contracting 

 muscle will be a retentive component than when 

 this angle is acute. 



(3.) Hence with the same muscular force an 

 obtuse myodynamic angle will afford conditions 

 of greater stability to the joint than an acute 

 myodynamic angle. 



(4.) But other things being equal, a right-myo- 



