148 THE PRINCIPLES OF MYODYNAMICS. 



antagonize the sterno-cleido-mastoids. (2.) 

 The right sterno-cleido-mastoid and the right 

 trachelo-mastoid will antagonize the left sterno- 

 cleido-mastoid and the left trachelo-mastoid. 

 (3.) The rotating components of the right 

 sterno-cleido-mastoid and the left trachelo-mas- 

 toid antagonize the rotating components of the 

 left sterno-cleido-mastoid and the right trachelo- 

 mastoid. 



139. (i.) The retejitive components of the mo- 

 tors of the sktdl luill co-operate, as well as the 

 moving components. ( 2.) The displacing com- 

 ponents of the antagonizing motors of the sknll 

 will also antagonize each other; and, as the 

 antagonizing groups have displacing compon- 

 ents acting in different directions — that is, in 

 opposite directions, these groups of displacing 

 components will counteract each other, and the 

 cranio-vertebral joint will be in a condition of 

 permanent stability. (3.) And, in any case, the 

 retentive components are greater than the dis- 

 placing components of the head-motors. 



