70 THE SURGICAL ANATOMY OF THE HORSE 



near the cartilages. Another condition which might result is the 

 formation of an abscess. 



Tumours. — Tumour-like growths are not infrequently found in the 

 larynx, the exact nature of which has not been determined. 



Operations on the Larynx 



Accurate diagnosis of affections of the larynx is attended by 

 considerable difficulty. The framework of the organ being made up 

 of somewhat rigid cartilage, internal growths produce little if any 

 change in the external appearance of the part. 



In most cases there is respiratory difficulty, and frequently also 

 interference with deglutition. 



In the horse the use of the laryngoscope is not very satisfactory, on 

 account of the great length of the cavity of the mouth. The hand may, 

 however, be placed in the pharynx and the presence of abnormal 

 growths ascertained if these should be placed near the pharyngeal 

 opening, i.e., near the base of the epiglottis or apices of the arytenoid 

 cartilages. 



In suspected cases by far the most satisfactory method is to 

 open into the larynx — an operation which is by no means difficult. 



Laryngotomy 



This is the term applied to the operation of opening into the 

 larynx. The animal should be cast, placed upon its back, and 

 the occipito-atlantal joint fully extended. This will increase the 

 distance between the body of the thyroid cartilage and the cricoid, 

 and permit of a more extensive view of the interior of the chamber 

 when the incision into it has been made. 



The parts should now be palpated — the location being determined, 

 first of the uppermost two or three tracheal rings, then the cricoid 

 cartilage, and lastly the pomum adami or body of the thyroid. This 



