SPRAIN. 



Juries, when they affed the immoveable joints, like thofe 

 betwixt the tibia and fibula, thofe betwixt the bones of the 

 pelvis, Sec. But, as Boyer has obfervetl, it is plain that 

 thefe accidents do not at all differ from common fprains, 

 fince they cannot happen without a violent ftretching and 

 even a rupture of the ligaments. 



The orbicular joints, thofe which allow to the bones the 

 mod varied and extenfive motions, are fo difpofed, that 

 their lipjaments, which arc protefted by a great number of 

 powerful mufcles, can only fuffer a confiderable extenfion 

 by an extraordinary effort ; and when it is adequate to pro- 

 duce this extenfion and rupture of the ligaments, the dif- 

 placemcnt which follows is necefTarily permanent, in confe- 

 quence of the fpherical form of one of the articular fur- 

 faces ; which form will not permit a fpontaneous reduftion. 

 On the contrary, in the ginglimoid joint?, and thofe 

 which refemble them in the trivial degree of their motions, 

 which are ufually limited to two alternate direftions, and 

 fometimes very obfcure, the natural relations of the bones 

 are aflured by the difpofition of the articular furfaces them- 

 felvcs, and by the ftrength of the hgaments, but hardly at 

 all by the mufcles. The aftion of thefe laft organs, confe- 

 quently, not increafing the refiftance made by the ligaments 

 in cafes of neceflity, in proportion to the violence which 

 operates, the latter parts are the more apt to be ftretchcd 

 and ruptured. On the other hand, as the furfaces of thefe 

 joints are generally extenfive, and cannot be forced away 

 from each other witliout great difficulty, the effort which 

 tends to feparate them, for the moft part only occafions a 

 ftretching and rupture of the ligaments. Hence, difloca- 

 tions are very common in the orbicular joints, and fprains 

 are moll frequent in thofe of the ginglimoid kind. The 

 ankle joint, which affords a ftriking inftance of the condi- 

 tions jult now explained, and which is befides expofed to 

 confiderable and frequent fhocks, is alfo that in which fprains 

 are mollly obferved. Then follow the articulations of the 

 bones of the tarfus, of the wrift, knee, and elbow, in which 

 lall a fprain is not fo often met with, notwithftanding the 

 fuitable difpofitions in appearance ; for the ligaments which 

 ftrengthen this joint being extremely flrong, an exceffive 

 violence is requifitc to ftretch or break them, and tlien it 

 is always capable of alfo occafioning a dillocation. 



The differences of fprains depend upon the importance of 

 the joint, the degree of violence which has been applied, and 

 the extent of the diforder attending thefe cafes. Confe- 

 quently, fome fprains are flight, the ligaments having been 

 merely ilretched, while others are fevere, the ligaments and 

 furrounding cellular fubflance having been lacerated, and the 

 tendinous nerves and veffels of every kind, and even the flcin 

 itielf, more or lefs violently ftretched. 



When a fprain occurs, the external violence which pro- 

 duces it, mull either aft fo as to carry the motions of a 

 ginglimoid joint beyond their natural limits ; or fo as to 

 cauTe movements in a direftion in which they arc not natu- 

 ral ; or, laltly, fo as to make a joint move, which in the 

 natural Hate performs no motion whatfoever. Thus, in a 

 fall upon the hands, where the extenfion or flexion of tlic 

 wriil is forced, a fprain is very liable to happen. In a fall 

 upon the feet, where one of the two, being in the itate of 

 add'idlion, or abduftion, fupports nearly the whole weight 

 of the body ; alfo in falls backward, where the point of the 

 foot is fo locked as not to allow any motion of the leg back- 

 ward ; and when the fole of the foot is twided inward while 

 a patient is running quickly ; tlie ankle, or joints of the 

 tarfus, or all together, are liable to be fprained. With re- 

 gard to the ankle, it may be remarked, tliat there arc cafes, 

 in which a predifpofition to fcrofula afts alfo a» a predif- 



voL. xxxni. 



pofition to fprain. We allude to inflances, in which the 

 articular extremities of the long bones having been enlarged 

 at an early period of fife, the ligaments of the neighbouring 

 joint have fuffered a confiderable elongation, or relaxation. 

 This occurrence, which is particularly obfervable at the 

 lower end of the tibia, makes the foot flat, and its articula- 

 tion much freer and weaker than it ought to be ; and 

 patients who are thus formed, are alfo more fubject to 

 fprains. Under thefe circumllanccs, it is not uncommon to 

 fee the fame accident happen fcveral times to the fame joint. 

 With refpeft to the fort of injury winch has received the 

 name of dia/lqfis, it is difficult to comprehend the pofTibility 

 of it, unle^ combined with a frp.dure of one of the two 

 bones. In taking for example the bones of the leg, it is 

 difficult to conceive how the lower articuhtion of the tibia 

 with the fibula can be affedled by external violence ; how 

 the furfaces of this joint can be feparateJ, its ligaments 

 elongated or ruptured, without there being at the fame time 

 a frafture of the fibula. It is an accident which to Boyer 

 feems very difficult to prove. A mere fcparation of the ar- 

 ticular furfaces, without frafture, would hardly admit of 

 detedion, becaufe the fwelling, which takes place almoft 

 immediately, muft hinder the examination of the parts. 

 Boyer thinks it extremely probable, that, in many cafes, 

 the confequences of an undifcovered fraAure of the fibula 

 have been raiflaken for the confecutive proofs of a diaflafis. 

 Sprains are accompanied with a variety of fymptoras, 

 amongft which pain and fwelling come on immediately. It 

 is eafily comprehenfible, that the ligaments, and other foft 

 parts which furround a joint, cannot be ftretched and more 

 or lefs torn, without an inllantaneous pain being excited 

 proportionate to the fenfibility of tliefe parts, and the de^ee 

 of violence which they have fullained. The pain and irrita- 

 tion are foon followed by fwelling, which, from being at 

 firft inconfiderable, afterwards increafes, and at the end of 

 four and twenty hours it is ufually at the highell degree, 

 and exhibits figns of the prefencc of inflammation. The 

 blood, which efcapes from the fmall ruptured veffels, paffe* 

 into the cellular fubftance, and occafions an ecchymofis, 

 which fometimes extends a great way. Immediately after 

 the accident, the joint is capable of performing all its mo- 

 tions ; but, as foon as the fwelling has taken place, thefe 

 motions are impeded, and, on force being ufed to make the 

 joint move, acute pain is produced, and Uie cafe is rendered 

 worfe. 



When a fprain is flight, it is a difeafe of little confe- 

 quence, and eafily cured. The pain gradually diminifhes, 

 the fwelling and tenfion difappear, the ecchymofis is dif- 

 perfcd, the motion of the limb is rellored, becoming daily 

 more and more extenfive, and the joint in due time returns 

 to its natural Hate. But when a fprain happens to a joint, 

 the motion of which is naturally very co.ifined, and which it 

 flrengthened by exceedingly flrong ligaments, wliofc re- 

 fiftance can be overcome only by great violence, the fymp- 

 toms are generally very fevere, and difappear much more 

 flowly. Then, according as the ligaments have fullered 

 more or lefs, and as the fwelling of the foft parts hai been 

 more or lefs confiderable, fometimes the joiut remains af- 

 fefted with a weaknefs, which renders it particularly fufcep- 

 tible of the fame accident ; fometimes it contrads a IlifTnefs, 

 which renders all motion extremely difficult, and which doc« 

 not go off till after a very long while ; and, indeed, occa- 

 fionally, fucli rigidity lalts <luring life. 



In fubjcdis who are well formed, and free from all confti- 



tutional difeale, it feldom happens that a fpr. in, even the 



moll confiderable, has any other confequences but thofe 



which have jull now been defcribed. Serious errors in the 



^ G treatment, 



