119 



development of the new curve, and, of course, are 

 greatest at the moment of discharge, when the shape 

 of the spine changes. 



§ 117. In connection with these movements, we 

 think one may trace the relative workings of the 

 psoce muscles and the diaphragm. — of the small 

 oblique muscles at the back of the head and the 

 sterno-raastoids — of the muscles which from the 

 upper part of the shoulder blades, converge at the 

 back of the head, of the muscles tvhich, from the 

 back, pass to the arms, and of the muscular combina- 

 tions which, acting between the lower end of the 

 breast bone and the collateral sides of the pelvis, 

 straighten the tractions of this bone from diagonal 

 to collateral. 



In tracing the action of the bony skeleton, as 

 affected by these muscles, we shall leave out of 

 mention the Latissimus dorsi, the obhque muscles 

 of the head, and those connecting the shoulder 

 blades and the head, because we think that their 

 workings may be more clearly defined by tracing 

 the shoulder blades as resting on and following the 

 shape of the chest, and that the movements of the 

 head are sufficiently clear of themselves. 



§ 118. Taking a general view of the action of 



