468 THE RESPIRATORY SYSTEM. 



Tuberculous and Syphilitic Inflammation with the usual morphological 

 characters of these processes are common in the nasal cavities. 



TUMORS. 



Aside from the nasal polyps which may be adeuomatous in character, 

 the most common tumors are epithelioma and sarcoma. 



Dermoid cysts have been described. 



The pharynx may be the seat of lesions similar to those just described 

 as involving the nasal cavities. 



The Larynx and Trachea. 



Malformations. 



The larynx and trachea may be absent. The larynx may be abnormally large or 

 small ; the epiglottis also may be too large or too small, or may be cleft. There may 

 be communications between the trachea and the oesophagus, aud then the pharynx gen- 

 erally ends in a cul-de-sac, and the oesophagus opens into the trachea. There may be 

 imperfect closure of the original branchial arches, so that there are fissures in the skin 

 leading into fistula? which open into the pharynx or trachea. The fissure in the skin is 

 small and is situated about an inch above the sterno-clavicular articulation, usually on 

 one or both sides, more rarely in the middle line. Individual cartilages, as the epiglot- 

 tis, or one or more rings of the trachea, may be absent, or there may be supernumerary 

 rings. The trachea may divide into three main bronchi instead of two, and in that case 

 two bronchi are given off to the right lung and one to the left. The trachea may be 

 on the left side of the oesophagus or behind it. 



(EDEMA OF THE GLOTTIS. 



This is a condition in which there is an accumulation of serous fluid 

 in the subnmcosa of the upper part of the larynx. This may be due to 

 simple circulatory disturbances, local or general, or it may be inflamma- 

 tory in character. The greatest accumulation of fluid is in places in 

 which the submucous tissue is abundant and loose in texture, as in the 

 posterior wall of the epiglottis, in the ary-epiglottidean folds, and in the 

 false vocal cords. The swelling of these parts may be so great as to 

 occlude the air passage. After death the cedeinatous swelling may 

 largely disappear, but the mucous membrane may be left unusually 

 wrinkled and flabby. 



(Edema of the glottis is comparatively infrequent in association with 

 such heart, kidney, and lung lesions as lead to general oedema. It is, on 

 the contrary, frequent in connection with various forms of laryugeal 

 inflammation. 4 



INFLAMMATION. (Laryngitis.) 



Acute Catarrhal Laryngitis. This occurs as an independent process as 

 a complication of the infectious diseases, or may be induced by the inha- 

 lation of irritating vapors and of hot steam and smoke. The inflamma- 

 tion varies in its intensity in different cases. The mucous membrane is 

 at first congested, swollen, and dry; then the mucous glands become 



