90 



ent, on looking at this arrangement, that although 

 the secondary sections of the anterior winding- 

 lines (§§ 25, 68) might be easily established, from 

 " points of application " acting on an anterior 

 plane section, just below the first pair of ribs, and 

 also the primary sections of the posterior Hnes^ 

 from " points " on a posterior plane at the summit 

 of the lumbar vertebrse, yet the estabhshment of 

 the primary sections of the anterior lines, and of 

 the secondary sections of the posterior lines, would 

 be seriously interfered with, unless the upper part 

 of the chest be allowed considerable eccentric 

 movement, such as shall successively bring its rib 

 articulations under the course of the sectional 

 lines referred to. 



This eccentric movement is allowed and regu- 

 lated by the action of the neck S, the lower part 

 of which moves with the upper part of the chest, 

 and must adjust itself by a virtual joint, in which 

 the lowest neck vertebra and one or two of the 

 most anterior ribs take part, and which we shall 

 call the " neck root joints 



The head condyles are here essential, in their 

 character as two separate ball and socket joints, 

 because of the break in the " composite " move- 

 ment caused by the interposition of the breast- 



