348 



RESPIRATION. 



[CH. xxiv. 



movement of the front extremities of the ribs is of necessity 

 accompanied by an upward and forward movement of the sternum 



14 A. 



Fig. 318. Diagram of axes of movement of ribs. 



to which they are attached, the movement being greater at the 

 lower end than at the upper end of the latter bone. 



Fig. 319. Diagram of movement of a rib in inspiration. 



The axes of rotation in these movements are two ; one corre- 

 sponding with a line drawn through the two articulations which 

 the rib forms with the spine (a, b, fig. 318); and the other with 



