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be no easy task) — but the positions of every sepa- 

 rate point of this figure depend on the movement 

 of some more inward and more central point. 

 Thus the hip-bone which carries the thigh-bone 

 socket is a more inward point than the thigh-bone 

 and is a controlling basis for its motion, as also 

 for that of the leg and foot. So is the motion of 

 the shoulder-blade, which carries the arm-bone 

 socket, a controlhng basis for the arm, the fore- 

 arm and the hand. 



Further, both the hip-bones and shoulder-blades 

 depend for a basis of movement upon the spine 

 and indeed finally upon the head, this last being so 

 situated in respect to the spine that the relative 

 positions of the articulating surfaces in their com- 

 mon joint, at the summit of the neck, determine 

 the shape assumed by the spine, and consequently 

 the angles at which the forces acting from the 

 spine press down their points d'appui against the 

 ground, and thus give the direction of the ensuing 

 movement. 



§ 8. The hip-hones are soldered into one peice 

 with the lower end of the back-bone, and therefore 

 depend directly upon it for every movement. The 

 shoidder-Uades, on the other hand, are connected 

 with both the back-bone and neck (the two together 



