130 THE PRINCIPLES OF MYODYNAMICS. 



rotating function of tJie flexors of the thigh — 

 that is, the psoas magnus and the ihacus : — 



When the thigh is parallel with the long axis 

 of the body, and when the femoral neck is of 

 average length, and when the trochanter minor 

 is of moderate length, the insertion of the 

 flexors of the thigh, during in-rotation of the 

 femur, will move forward and inward faster than 

 backward and outward, inasmuch as the femoral 

 neck makes a lonofer radius than the semi-diam- 

 eter of the shaft of the femur plus the height of 

 the trochanter minor : The same may be said 

 when the thigh is abducted. Under the condi- 

 tions named, the psoas magnus and the iliacus 

 are in-rotators of the femur. But when the 

 thio-h is adducted, and when the trochanter 

 minor is largely developed, so as to make a 

 lever long enough, the psoas magnus and the 

 iliacus are out-rotators of the femur. llicsc 

 imiscles are flexors of the thigh. 



12 5. The triceps rotator of the femur is made 

 up of the gemelli and the obturator internus. 

 In general, when the long axis of the femur and 



