INCISIONS. 133 



Another manner of incision from within outward is to make a 

 fold of the skin, as ah-eady described, and by pushing the straight 

 bistoury through its base, and turning the edge, completing it by 

 a single stroke upward to the summit. When an incision ah*eady 

 existing must be enlarged, the bistoury, held in the second posi- 

 tion, is introduced flatwise under the skin as far as is necessary ; 

 then turned to bring the edge upward and pushing the point 

 through the skin by drawing the instrument outward, the flap of 

 sMn between the two openings is di\dded at one stroke. 



A fourth procedure is known as the incision with flaps. It is 

 principally used in amputations. With the left hand the surgeon 

 grasps a fold of skin, pushes the bistoury held in the first position, 

 but flatwise, through its base, and in drawing it out obhquely 

 by a sawing motion cuts out a semi-circular flap of the required 

 dimensions. 



With the Director or Guide. — Incisions in this mode are made 

 to remove compressions caused by strictures, or to estabhsh a free 

 exist to pus by a counter opening. Either the finger or the 

 grooved probe or the director may be used as a guide to the in- 

 strument. In all cases there must already exist a natural or acci- 

 dental opening to allow the introduction of the director. Several 

 modes of procedui-e are employed according to conditions and ob- 

 jects in view. In one, the director being introduced into the tract 

 to be enlarged, as far as the point where the incision must end, 

 the bistoury, held in the first or second position, with the edge 

 turned upward, is made to slide into the groove of the director, 

 forming with it an acute angle, and pushed in its whole length, 

 dividing the tissues until it reaches the end of the groove, when 

 it is withdrawn in the perpendicular position. A second mode 

 is to carry the bistoury flatwise alongside the director, and when 

 reaching its end to turn the instrument with the edge upward, 

 first thrusting the point through the tissues and tegument, and 

 completing the incision by withdrawing the bistoury outward and 

 toward the operator. In a third procedvire, which is that of mak- 

 ing .counter openings, the probe or director is introduced into the 

 wound, and at its deej) end, to push toward the skin until it raises 

 it from the inside or can be felt through it ; an incision from with- 

 out inward is then made at that point, and the director being ex- 

 posed, the bistoury is engaged in its groove and pushed alongside, 

 dividing the tissues at wiU in length and in depth, and establishing 



