WOUNDS. 



Compression, Concussion, Extravasation, Head, In- 

 juries of, and Trepanning. 



" Of Cuts or incifed W'ez/nij.— Sharp-edged inftruments may- 

 produce a divifion of the parts upon which they ad, alto- 

 gether on the principle of direft preffure ; in which cafe, 

 they may be regarded as operating in the manner of a wedge. 

 In other inflances, they both prefs and faw at the fame 

 time, and then the folution of continuity is made with more 

 facility, and carried to a greater depth, becaufe the fibres 

 are elongated in the direftion in which the inftrument faws, 

 as well as in that in which it preffes. 



In whatever way a cutting inftrument operates, feveral 

 confequences refult from the divifion of the parts, itt, An 

 effufion of blood from the divided veffels. adly. Pain, 

 arifing from the divifion of nerves. 3dly, A gaping of the 

 wound, or feparalion of its edges from each other. 



Anatomy teaches us, that almoft every part of the body 

 is furniflied with a confiderable number of blood- veffels, 

 which indeed exift in fuch myriads, that it is impoffible to 

 prick the flcin witix the point of the moft minute needle, 

 without opening one or more ramifications of veffels con- 

 taining blood. But this effeft always happens in a ilill greater 

 and more remarkable degree, when the divifion, caufed by 

 a fharp-edged inilrument, is at all extenfive. 



If the wounded veffels are of fmall fize, the blood iffues 

 from them only in moderate quantity ; but when they are 

 large, the hemorrhage is more copious, and it may be fo 

 rapid as to prove almoil inftantly fatal. Many of the phe- 

 nomena of hemorrhage have been already confidered in an- 

 other place (fee Hemorrhage) ; and, on this account, we 

 fhall not have occafion now to tra%'el over the whole of that 

 interefting topic agrjn. There are, however, certain parts 

 of the fiibjeft which muft fall under conlideration in the 

 courfe of this article ; and in mentioning them, we (hall take 

 the opportunity of noticing a few ingenious fuggellions, 

 which have been made fince the period when the above- 

 mentioned article was written, and which, when further in- 

 velUgated, may lead to very important improvements in 

 tlie treatment of wounds. 



It has been ftated, that hemorrhage is one of the circum- 

 ftances which render wounds complicated ; yet it is to be 

 underftood, that when the bleeding is not lo confiderable as 

 to hinder the union of the parts, and a further effufion of 

 blood can be prevented by the very fame prefiure vi'hich is 

 neceffary to promote this union, the cafe is always regarded 

 as a fimple wound. Such is that which is produced by the 

 operation for the harelip, &c. 



The fame experiment which demonftrates the prefence of 

 blood-veffels in every fituation, namely, pricking any part 

 of the body with a needle, proves alfo that filaments of the 

 nerres are found every where, and at every point ; for the 

 nightefl prick of the /kin occafions pain, and pain cannot 

 happen except where there are nerves. But wounds are 

 oblerved to be attended with a pain, which is more or lefs 

 zcute, according to the kind of cutting inftrument with 

 which they are infllfted, the extent of the divifion, and 

 efpecially according as the wounded perfon happens or not 

 to be in expeftation of the receipt of the injury. A patient, 

 on whom an operation is to be performed, tJrns his whole 

 attention to the effeft which the ufe of the knife will pro- 

 duce upon his feehngs, and he fuffers a great deal ; but if 

 an incifion be made when not expefted, or a foldier be 

 wounded in the heat of battle, the injury is fometimes not 

 perceived till the bleeding attrafts notice. 



Immediately a part is divided with a cutting inftrument, 

 the edges of the wound feparate more or lefs diftantly from 

 each other, and the injury prefents a gaping appearance. 



This is an occurrence which is owing to feveral caufes, ne- 

 ceffary to be underftood by every furgeon who is defirous of 

 knowing the beft mode of obviating it. 



The firft caufe of the feparation of the lips of a wound 

 from each other is, no doubt, the thicknefs of the inftru- 

 ment with which the folution of continuity is made. A 

 cutting inftrument, afting like a wedge, muft unavoidably 

 feparate the parts between which it enters ; but if this 

 were the only caufe, the gaping of a wound would be very 

 inconfiderable, fince the blades of moft cutting weapons arc 

 extremely thin. We find, however, that the oppofite fur- 

 faces of many wounds are drawn away from each other 

 feveral inches, and the caufes to which the phenomenon is 

 to be afcribed are the elafticity and contraftile nature of 

 the divided parts ; fometimes one of thefe properties ope- 

 rating fingly, fometimes both of them together in the fame 

 wound. 



Elafticity is a quality which belongs to all animal fub- 

 ftances, and it is inherent in them even after they have bees 

 deprived of life ; but it does not prevail in an equal degree 

 in every texture. Thus, the gaping of a wound depending 

 upon this caufe varies very confiderably, according to the- 

 nature of the divided parts. The edges of an incifion made 

 in the flcin become widely drawn afunder, becaufe the inte- 

 guments are endued with great elafticity. The cellular mem- 

 brane, wlien cut, gapes very little, becaufe it is lefs elaftic. 

 The mufcles alfo are not remarkably elaftic ; yet wound; 

 of them, efpecially tranfverfe wounds, always have thei 

 oppofite fides feparated a vaft diftance from each other : bu 

 this is a circumftance which is owing not altogether to the 

 elafticity of the parts, but partly to their contraftile 

 powers. 



The feparation of the edges of a wound is not always in i 

 proportion to the elafticity of the wounded part ; it is like- 

 wife proportioned to the tenfion of this part at the very mo- 

 ment of the injury. An exceedingly fimple experiment 

 proves the truth of this obfervation : if the flcin which co- 

 vers the knee be divided tranfverfely in the dead fubjeft,, 

 while the leg is bent upon the thigh, and another fimilar in- 

 cifion be made in the other knee, while the leg is extended, 

 the feparation which happens between the edges of the divi- 

 fion will be found to be much greater in the firft than in the 

 fecond example. 



The contraftile power, or irritability, which is a peculiar 

 property of mufcular fibres, and by virtue of which they 

 tend continually to ftiorten themfelves, is the moft powerful 

 caufe of the feparation which occurs between the oppofite 

 fides of a tranfverfe wound of any mufcle. The fepa- 

 ration thus produced is the greater in proportion as the cu; 

 mufcular fibres are longer, inafmuch as the contraftion of 

 which the mufcles are capable, by reafon of their contraftile 

 power, is itself in a ratio to the length of the mufcular 

 fibres. Thus, as Boyer obferves, if two mufcles be divided 

 tranfverfely, the fibres of one of which are three times ai> 

 long as thofe of the other, the feparation which takes place 

 between the edges of the wound of the former will be three 

 times as great as what follows, between the fides of the 

 divifion made in the latter. 



The force with which the feparation is produced by the 

 contraftile power of the mufcles, is not in proportion to the 

 length of the mufcular fibres, but to their quantity. Each 

 mufcular fibre being regarded as a feparate diftinft power, 

 it is obvious, that the more thefe powers are multiplied, the 

 greater muft be the effeft refulting from their aftion. 



It appears alfo, that in addition to the firft contraftion of 

 a divided mufcle, a fecondary and increafed contraftion of 

 ilie part may be excited, when it is expofed and irritated. 



From 



