128 



THE PRINCIPLES OF MYODYNAMICS. 



Upward when the femoral neck is broken ; (2.) 

 to prevent upward dislocation of the femur : — 

 Also the obturator internus will have similar, 

 though less marked, functions. 



12 1. The biceps cruris, the semi-membran- 

 osus, the semi-tendinosus, the gracilis, the 

 sartorius, and the rectus femoris span the. hip- 

 joint and the knee-joint. The gluteus maximus, 

 the gluteus minimus, the gluteus medius, the 

 tensor vaginae femoris, the psoas magnus, the 

 iliacus, the pectineus, the adductor magnus, the 

 adductor longus, the adductor brevis, the obtur- 

 ator externus, the triceps rotator, and the pyri- 

 formus span only the hip-joint. — The sartoruLS 

 flexes, out-rotates, and abducts the thigh : and 

 flexes the teg. 



122. The shaft of the femur does not rotate 

 directly on its own axis ; it rotates indirectly, as 

 it moves forward and backward under the action 

 of rotator muscles. When the femoral neck is 

 broken, the shaft of the femur can rotate di- 

 rectly on its own axis. 



123. When the femur is flexed and extended, 

 the femoral neck will rotate nearly on its own 



