104 PRACTICAL ANATOMY. 



first costal cartilages, and the manubrium. The lower 

 opening of the chest is irregular and is limited anteriorly 

 by the ensiform appendix, the costal cartilages, the free 

 extremities of the eleventh and twelfth ribs, the twelfth 

 rib, and twelfth dorsal vertebra. Along the median 

 line, posteriorly, are the spines of the dorsal vertebraa, 

 and on either side the chest presents the broad dorsal 

 grooves, which are about one and a half inches in 

 depth close to the spinous processes, but which become 



FIG. 47. THE OSSEOUS THORAX. 



1, manubrium; 2, gladiolus; 3, xiphoid appendix; 4. first dorsal vertebra ; 5, last dorsm 

 vertebra ; 6, first rib. 



shallow externally toward the angles of the ribs, which 

 serve to limit the grooves. They lodge the dorsal 

 muscles, especially the fourth and fifth layers. Later- 

 ally, the chest is convex from before backward; ante- 

 riorly the chest is flattened, though prominent below, due 

 to the advance of the lower part of the sternum. In 

 the lower animals, as a rule, the chest is flattened from 

 side to side, so that naturally they rest upon the side ; in 

 man the converse is true, for in conditions of muscular 

 relaxation and at death he gravitates upon his back. 



