FRACTURES OF THE TRACHEA. 
189 
two arytenoids sink downwards and approach each other, and in paralysis 
may even come in contact, completely closing the larynx. If not pio- 
vided with the instrument, one may divide the cricoid cartilage and 
crico-thyroid ligament, and by introducing the forefinger through the 
opening, directly examine the arytenoid cartilages. Whilst in the 
normal larynx they make distinct to-and-fro movements, especially 
during forced inspiration, in diplegia laryngis they are found to sink 
downwards in the larynx. In this disease tracheotomy alone can lestoie 
the animal’s usefulness. 
Starting with the hypothesis that the cause of paralysis is situated m the 
intrathoracic portions of the nerve, MacDonald attempted to unite ie 
ascending (cervical) portion of the recurrent to the spinal accessory, and t ius 
to “short-circuit” the nervous impulses. Both he and Haslam claim to 
have had good results. Other operators, however, have been unsuccessful, 
partly because of the necessarily delicate manipulation involved, but. more 
probably because of the serious changes that had already occurred m tire 
nerves and muscles. 
(3.) FRACTURE, DEFORMITY, AND STENOSIS 
OF THE TRACHEA. 
Injuries to the trachea having already received attention as compli¬ 
cations of wounds in the neck, it only remains to consider those 
subcutaneous solutions of continuity which, when affecting the carti¬ 
laginous rings, are described as fractures. These injuries result from 
the forcible action of blunt bodies on the air tube ; in horses are caused 
by the impact of the carriage pole, by rushing against projecting bodies, 
or by falling whilst haltered tightly. Fractures of the cartilages, or 
rupture of the inter-annular ligaments, in dogs are caused by their being 
captured with a wire snare. 
Bru noted rupture of the ligaments between the first three tracheal rings in 
a mule Walley saw a fox terrier in which the trachea was torn across ; death 
occurred very rapidly. Cajory found the trachea almost completely torn from 
the larynx in a horse which had died in the stall after a sudden attack of 
dyspnoea. Von Bockum-Dolffs saw a horse suffer from emphysema of the 
neck and severe dyspnoea, in consequence of having run against the pole ot a 
passing carriage. 3 Tracheotomy removed the difficulty m swallowing and 
breathing, and the animal again became fit for woik. 
But such injuries cannot always be successfully treated; deformities 
of the trachea sometimes result; extensive cicatrices produce stenosis of 
the trachea, accompanied by dyspnoea. Schwanefeld describes a horse 
in which the trachea was flattened about the middle of the neck and 
oreatly narrowed. The presence of a stallion in the stable excited it 
and induced suffocation. Some deformities of the trachea are clearly 
congenital. Occasionally the posterior ends of the tracheal rings are 
