SYSTEMATIC ANALYSIS OF THE BODY. 45 



as a greater variety of motions and more extended ones 

 are required; but the general character of the two must 

 be similar. 



79. THE UPPER EXTREMITIES ARE COMPOSED of the 

 shoulders, the upper and lower arms, and the hands. 



80. THE SHOULDERS ARE NOT A PART OF THE TRUNK, 

 but are movable upon the upper part of it, in order to 

 bestow more extended motion upon the arms and hand, 

 that must serve the mind by great latitude of motion at 

 times. They are hinged through the inner end of the 

 collar-bone to the upper end of the breast-bone, which is 

 the centre of a partial circumference, through which the 

 shoulder can move. 



81. THE UPPER ARM must, like the upper leg, be 

 fastened above by a rotary joint, so as to have motion in 

 every direction. 



82. THE LOWER ARM, or the forearm, must be fast- 

 ened to the upper by a hinge-joint, allowing upward or 

 forward motion, just the reverse of that of the lower 

 leg. 



83. Inf. THE SIMILARITY OF THE UPPER AND LOWER 

 EXTREMITIES was not accidental, nor a necessity, but is 

 owing to the similarity of purpose ; for in any case of 

 dissimilarity of purpose there is a corresponding dissimi- 

 larity of structure in them. 



84. THE ENTIRE LENGTH OF THE FOREARM MUST BE 

 A JOINT, adapted to allowing a rotary motion of the hand, 

 which could not be gained by any construction of the 

 wrist-joint 5 but by simply rolling the lower end of one 

 bone of the lower arm over the other, the hand being 

 attached to the former is carried with it and made prone. 



85. THE HAND is ATTACHED to one of the bones of 

 the lower arm by a compound joint, allowing less mo- 

 tion than the rotary, and not restricting it as much as 

 the hinge. 



86. ALL THE DIVISIONS OF THE UPPER EXTREMITIES, 



79. Of what arc - 9 80. What, are - ? 81. What must shoulder joint be ? 82. 

 How must the - be fastened ? 88 What is Inf. in regard to - ? 84. Why must ? 



