122 



ACUPRESSURE. 



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torsion). If the vessel is a large one, it should be held with narrow 

 forceps, applied transversely, while the torsion forceps, held parallel 

 to the long axis of the vessel, are quickly turned in one direction. 

 As in ligation, the middle and internal coats are ruptured, and 

 become induplicated ; the external coat being stretched and twisted 

 forms a kind of cap, which covers the clot, and gives it much greater 

 firmness. Ligation, however, is always more certain than torsion. 

 In arterioles of considerable size, moreover, the fibrous coat may 

 untwist, giving rise to secondary haemorrhage. 



Forcipressure by means of artery forceps has largely replaced other 

 means of checking bleeding. It consists in applying to the mouths 

 of divided vessels special forceps (Wells' form is the best), which 

 are left in position for a varying time, sometimes until the vessels 

 are blocked by clot, sometimes only until ligatures can be applied. 



If during operation a small artery 

 is divided forceps are immediately 

 applied. By using a number incisions 

 may be made through very vascular 

 tissues with little interruption or loss 

 of blood. To keep the operative 

 field clear they are held to one side 

 by an assistant. It is not necessary 

 that all should be left in position 

 until the end of the operation ; 

 arteries of very small dimensions, if 

 compressed for a few minutes, no 

 longer bleed when the forceps are 

 removed. Should a large vessel be 

 divided, it can be grasped and closed 

 with Wells' forceps, and immediately ligatured ; this prevents the 

 seat of operation being obscured with blood. 



Needless to say, forceps, threads, and instruments must all be 

 aseptic, an indispensable condition if one wishes to effect primary 

 union 'or prevent accidental infection. 



Acupressure never found much favour in veterinary practice as 

 compared with human surgery, because animals are too difficult to 

 control. At the present day it has lost much of its value, inasmuch 

 as materials for ligaturing vessels are available which can be left 

 permanently in position without danger. Acupressure is effected 

 by thrusting a pin vertically into the soft tissues about three eighths 

 to three fourths of an inch from the artery, carrying it in a horizontal 

 direction over or under the artery, and causing it to emerge a similar 



Figs. 162a, 162^.— Method of 

 practising acupressure. 



