132 ANATOMY FOE, NUESES. [CHAP. XII. 



movements of the cilia continually sweep this dirt-ladened 

 mucus upwards and outwards. 



The trachea measures about four and a half inches in length, 



FIG. 90. FRONT VIEW OF CARTILAGES OF LARYNX. Trachea and bronchi. 



and three-quarters of an inch from side to side. It extends 

 down into the thorax from the lower part of the larynx to 

 opposite the third dorsal vertebra, where it divides into two 

 tubes, the two bronchi, one for each lung. 



