TRACHEOTOMY. 
199 
then excising a half-round piece from the cartilages above and below, 
without, however, quite dividing these (fig. 88, c). Bending of the 
tracheal rings and stenosis of the trachea, which result from completely 
cutting through the cartilages, are thus avoided, Brogniez’s bronclio- 
tome likewise produces an oval cut, but can be replaced by a bistoury, 
deftly manipulated. The same remark applies to other instruments, 
Fig. 90.—Position of tracheal canula. a, Normal ; b, when too much curved ; 
c, when insufficiently curved. 
such as Marty’s tracheotome, which cuts a circular piece from the two 
cartilaginous rings, like a trephine. 
Tracheotomy is one of the simpler of equine operations, and is easily 
carried out with a little care. Its success depends greatly on the 
canula used. 
Many of those recommended can only be employed in connection with 
their appropriate tracheotomes, and, therefore, may be disregarded. The 
oldest (Barthelemy’s) consists of a metal tube, 4 to 8 inches in length and 
3 to 2 inches in width, bent at one end, and provided with a plate to prevent 
its entering the trachea too far. The edges of the plate and those of the 
lower end of the tube must be carefully rounded off to prevent their abrading 
the skin or mucous membrane. The tube, while nearly filling the tracheal 
space, must not press on the mucous membrane, nor must the soft tissues of 
the neck be pinched. The bend must be confined to the uppei end, and must 
be suited to the thickness of the parts between the skin and front wall of the 
trachea. Where the bend is too short, not only will the skin and muscular 
tissues be bruised, but the lower end of the tube will press against the posterior 
wall of the trachea and produce inflammation with proliferations, leading to 
stenosis (fig. 90, c). Where the bent portion is too long, there is undue space 
between the plate and the skin, and if such a tube be pressed home by 
tapes or straps, it becomes displaced and liable to injure both walls of the 
trachea (fig. 90, b). Tracheotomy tubes, formerly made of tm plate, are now 
much better manufactured of German silver. 
The objection to Barthelemy’s canula, viz., that it falls out easily, may 
partially be obviated by straps (with buckles), fastened m the eyes of the 
plate and passed transversely round the neck. They should not be carried 
