CHRONIC LARYNGITIS AND PERILARYNGITIS. 441 



recognised. Diagnosis is rarely aided by palpation of the trachea ; 

 but pressure on the diseased spot may, perhaps, increase or decrease 

 the dyspnoea. 



Prognosis is in general unfavourable. Abscess formation and 

 the discharge of pus into the trachea may occasion pneumonia. In 

 chronic laryngitis with thickening of the mucous membrane, resection 

 of the vocal cords may be serviceable. Prognosis of perilaryngitis 

 fibrosa depends in great part on the degree of 

 dyspnoea. Tracheotomy is certainly a palli- 

 ative. The prognosis of most laryngeal 

 tumours is unfavourable ; but pedunculated 

 growths, situated within the larynx, may 

 sometimes be removed without recurrence, 

 section being made of the cricoid cartilage 

 and first rings of the trachea. Where the 

 operation is unsuccessful, tracheotomy will 

 still render the animals workable. 



Treatment. Tumours on the epiglottis can 

 sometimes be removed in the same way as 

 pharyngeal tumours in cattle, by tearing them 

 away with the hand ; in dogs, with the 

 assistance of instruments. Dieck removed a 

 swelling as large as a hen's egg from the 

 epiglottis of a horse with a specially-con- 

 structed instrument in the form of a hooked 

 knife. Tumours on the vocal cords can be 

 excised. The horse should be cast, and, if 

 restless, anaesthetised. The hair over the 

 larynx is shaved, and a cut made through 

 the skin in the middle line, from the thyroid 

 prominence to below the 1st or 2nd tracheal 

 ring. After checking bleeding, the second cut Fig. 349-Tampon-cannula 

 . , ,. . ,. ,-,1 i! ■ -, t or Trendelenberg- cannula, 



is made, dividing the subscapulo-hyoideus and 



the sterno-thyro-hyoideus exactly in the middle line. This exposes 

 the cricoid cartilage and trachea, which are then incised. The edges 

 of the wound are held apart with broad hooks or retractors. Where 

 a tampon-cannula (Fig. 349) is available, it may be inserted in the 

 trachea to prevent entrance of blood. The finger is introduced into 

 the larynx, the vocal cords examined, and the tumour is excised with 

 scissors. Bleeding is slight, and is of no importance if a tampon- 

 cannula has been used. The tampon-cannula may be removed next 

 day, but, for safety, it may be left in position for some days, especially 



