228 DETAILED SYNTHESIS. 



on its under surface, to adapt it to the form of the ribs 

 in its natural position. 



389. THE SCAPULA is JOINTED to the chest only as 

 described, and merely rests on the back of its frame, 

 some muscles intervening and being attached to it. 



390. THE INTENT OF THE CONSTRUCTION OF THE 



SCAPULA was, to provide a sufficient surface for the at- 

 tachment of muscles adapted to move the shoulder, 

 which is, so to speak, pivoted on the clavicle, and can 

 be moved in a limited portion of the circumference of 

 the sphere of which the clavicle is the radius. 



391. THE MOVEMENT OB THE POSITION OF THE 

 SHOULDER-BLADE does not affect the size or form of the 

 chest. 



392. Remark. When the shoulders are drawn back, more of the 

 chest is observed in front of the arms than when the shoulders are for- 

 ward, hence drawing them back has been thought to enlarge the chest ; 

 but in fact the chest was so much the smaller behind the arms. 



393. CONSTRICTING THE SHOULDERS in any position 

 will only interfere with free movement of the chest, 

 and instead of enlarging it will only diminish the ca- 

 pacity of that part of the body. 



394. THE SCAPULA is JOINTED to the upper arm-bone 

 (Humerus) by a very shallow socket, to which the hemi- 

 spherical head of the humerus is adapted, so that the 

 arm can have a very extended motion ; and when this is 

 combined with the movements of the Scapula, and these 

 multiplied by the motions of the chest and spinal column, 

 the hand has an extent of motion adapted to any neces- 

 sary purpose. 



395. THE HUMERUS is WROUGHT at its lower extremi- 

 ty into two condyles, the internal and external, by which 

 it is beautifully jointed to one of the bones (Ulna) of the 

 lower arm. 



396. THE ULNA is the name of the internal bone of 



389. How -? 890. What ? 391. What said of -? 89& What said of -? 

 394. How ? 395. How ? 396. What ? 



