THORACIC CAVITY 



57 



removed, and are also bound together by areolar tissue, 

 which is often dense and fibrous in the adult, especially 

 around the lymph glands. 



The bronchus is always easily identified by the firm 

 elastic plates of cartilage which help to form its walls, as 

 well as by its posterior position. The pulmonary artery can 

 be distinguished, not only by its intermediate position 

 between the bronchus and the veins, but also, as contrasted 

 with the veins, by the greater relative thickness of its walls. 

 The lymph glands are easily recognisable in the adult by 



EPARTERIAL 

 BRANCH 

 OF RIGHT 

 BRONCHUS 



Bronchial 

 gland 



Pulmonary 



veins v 



Ligamentum pulmonis 



FIG. 24. -The two Pulmonary Roots transversely divided close to the 

 hilum of each lung. 



their black or greyish black colour, but in the young child 

 they are yellowish pink in colour and are not so obvious. 

 The bronchial arteries lie on the posterior faces of the 

 bronchi, if they are not well injected they are difficult to 

 trace, and the veins which accompany them are still more 

 difficult to secure. 



In both sides one bronchus and one pulmonary artery 

 enter the root of the lung, and two pulmonary veins leave it. 

 As the bronchus and artery enter the root the artery passes 

 in front of the bronchus, and after they enter the hilum of 

 the lung the artery descends behind the bronchus on its 

 lateral side. The pulmonary veins lie at a lower level than 



