DISCUSSION 



193 



be flexed or extended when the humerus is in any position, 

 and similarly with the hand in relation to the remainder of 

 the arm. This is not the case, however, with the hind leg. 



Fig. 37. Illustration of the tendinous and tonal action of the two-joint 

 flexors and extensors of the hind limb (partially after Bowen). (o) Rectus 

 femoris and gluteus superficialis anterior; (6) psoas magnus (long) and 

 iliacus (short); (c) adductor magnus (long), adductores longus and brevis, 

 quadratus femoris, glutei medius and minimus (short); (d) biceps, semi- 

 membranosus, semitendinosus, gracilis; (e) gastrocnemii and plantaris; 

 (/) tibialis anticus. 



When the femur is flexed, the tibia can not be extended more 

 than to an angle of about 120 degrees with the thigh. 

 When the latter is extended, the lower leg can also be fully 



