104 



OPERATIVE TECHNIQUE. 



The real puncturing instruments are suture and exploring needles 

 and trocars. 



Suture needles are held with the thumb on the concave, the index 

 and middle fingers on the convex surface. Fig. 123. In using small, 

 fine needles, a needle-holder is of great service, Figs. 155 to 157. 



Pins are grasped with the middle finger and thumb, the index 

 finger being placed on the head, or they may be inserted by means of a 

 needle-holder. 



The trocar consists of a pointed steel rod provided with' a metal 

 shield or tube, exactly corresponding with it in other respects but 

 a trifle shorter. The rod ma)' be of varying length and thickness, 

 straight or curved, cylindrical or oval. The point is usually tri- 

 angular in section. At the lower end of the cannula, where it abuts 

 on the handle, are one or a pair of rings to permit 

 of its being fixed into position b}^ tapes. As 

 a rule the upper end of the cannula discloses 

 two short slits, which permit tlie parts to spring- 

 slightly and apply themselves closely to a trifling 

 circular depression formed just below the point of 

 the trocar. This device causes the instrument 

 to enter much more easily, as the union of the 

 trocar and the cannula then presents no projec- 

 tion. The handle of the trocar is grasped in the 

 hollow of the hand, the fingers and thumb steady 

 the stem, and in use the instrument is thrust into 

 the cavity to be penetrated with a single rapid 

 movement. The cannula is then fixed with the 

 left hand and the stilette or trocar removed with 

 the right. While withdrawing the cannula the 

 skin in the neighbourhood of the puncture 

 should be pressed down with the thumb and 

 index finger of the left hand to prevent it being 

 Fig. 127. Fig. 128. lifted. 



Division of Hard Tissues. — The horn of the hoof is divided with 

 a special knife grasped with the whole hand. Fig. 103. Bones are 

 divided with drills, chisels, saws, and forceps. The bone is prepared for 

 sawing by removing the periosteum with a chisel or gouge, Figs. 127-8. 

 Files and rasps are sometimes used to remove sharp edges or projecting 

 points from sawn surfaces. In this connection^ the sharp spoon or 

 curette, Figs. 129-31, used for scraping diseased bones and cartilages, 

 unhealthy granulations, callous walls of sinuses, etc., deserves mention. 

 It is not sufficiently known or valued in veterinary surgery. It con- 



