CHATTER V. 



DIVISION OF TISSUES. 



Cutting and Puncturinc; Instruments. — The first method of 

 dividing soft tissues is l)y means of cutting instruments like knives or 

 scis-ors. 



Knives are of var^nng form and size : those in which the blade and 

 handle are immoveable are termed scalpels ; those in which the blade is 

 protected with scales and turns on a liinge. bistouries. 



Knives, again, may be divided into sharp-pointed and guarded or 

 probe-pointed ; either of these .ma\- be straight, convex, or concave. 



Scissors are either sharp or round pointed, and flat or curved in the 

 blades (see Figs. 75, 76, and 77, p. 83). 



In making primar}- incisions a knife w ith a convex cutting edge is 

 usuall\- employed, and is grasped after the manner of a table knife 

 (Fig. 92). In making long incisions the knife is held like a violin bow 

 (Figs. 93, 94). For liner dissection the knife is employed after the 

 manner of a pen (Fig, 95). 



^n dividing tissues from within outwards the knife is grasped in a 

 similar way, but the cutting edge is now directed upwards (Figs. 96, 97, 

 and 98). Incisions are made b}- a light, drawing movement of the 

 whole hand, usually from left to right, seldom in the opposite 

 direction. 



The parts to be divided should be rendered tense b\- placing the 

 thumb of the left hand on one side, and the index linger on the other 

 side of the line of incision, and employing gentle traction (Fig. 99)^ To 

 more effectually stretch the skin the operator may employ the fingers 

 of the left hand on one side, whilst an assistant exercises traction on 

 the other side of the line of incision (Fig. 100). When important vessels 



