1 834 



HUMAN ANATOMY. 



nerve , posterior crico-arytenoid t 



^^^ 



The 



cardial effusion ; irregular heart action. 



absence of vocal fremi- 

 tus ; increased area of 

 transmission of heart- 



. Thyroid cartilage 



FIG. 1558. 



id cartilage 



sounds. 



Of course, all oi 

 these symptoms are not 

 present in any given case 

 of mediastinal growth, 

 but some of them are 

 sure to be and can be 

 more readily understood 

 if referred to their ana- 

 tomical causes. 



The phenomena ref- 

 erable to the separate 

 subdivisions of the me- 

 diastinum can be classi- 

 fied only in a very gen- 

 eral way. It may be 

 said, however, that: (i) 

 The anterior mediasti- 

 num is the most fre- 

 quent seat of abscess ; 

 that its growths usually 

 begin in the thymus ; 

 and that the chief symp- 

 toms are apt to be those 

 of pressure upon the su- 

 perior vena cava, inva- 

 sion of the suprasternal 

 fossa, involvement of the 



Cervical glands bulging 

 the Ster- 



Trachea and bronchial tree, anterior aspect. K, A, right and left bronchus ; .- 



A left apical I.I..M. liux .livi.lm K int.. \.-ntral (a) and dorsal (a') branches; B, or CrOSlOn OI 

 omiiniiaiinn ,,f mam l-i-.n, lius ; '. /' . \mtral and dorsal branches; c, cardiac ^ 

 tiM'in hu. 



Growths of the poste- 

 rior and midillr mrdi.istinum are apt to originate in the lymph-nodes, and the chief 

 symptoms .in- those of pressure upon the pneumogastric, recurrent laryngeal orsym- 

 p.ithcti. nerves, th<- ^KMICI .i/v^os vrin, the oesophagus, and the air-passages. 

 urgent dyspnoea and troublesome cough are out of all proportion to the physical 

 S (Osier). 



THE TRACHEA. 



The tr.i. h< .1 or uitid|)i|><- (l ; ig. 1558) is a tube, composed of cartilage and mem- 

 .i--. r\t-ndin^ from the cricoid cartilage to a point opposite the disk below the 

 fourth thoracic vertebra, corresponding to the level of the junction of the first and 



