LUXATION. 



being thus partly the efFeift of the fall, and partly the efFeft 

 of fuch mufcular aftion. Whatever may be the manner in 

 which the caufes aft, luxations are always accompanied with 

 more or lefs laceration of the ligaments, and injury of the 

 other foft parts about the joint ; and in the orbicular articu- 

 lations, like thole of the ihouldcr and hip, the capfular liga- 

 ments are always torn. 



With refpeit to tlic general fymptoms of luxations we 

 need not dwell much upon pain and iiiaViilily of moving the 

 limb, as, at moil, they are only equivocal, and common to 

 didocations, fraftures, and fimple bruifcs. They are not, 

 however, l<fhe entirely overlooked, but (till in forming a 

 diagnofis we fliould endeavour to found it on the exiftence of 

 fymptoms manifeft to the fenfes, fuch as an elongation or 

 (hortening of the limb ; a change in its (hape and direction ; 

 and lailly, the abfolute impoffibility of performing certain 

 motions. 



A luxation cannot pofiibly exift, unlefs the affefted limb 

 is either lengthened, as happens in the lower extremity, when 

 the head of the femur palfes out of the acetabulura, in the 

 direction downwards and inwards, and rells on the foramen 

 ovale ; or fhortened, as takes place when the fame bone is 

 luxated upwards and backwards, and has its head thrown to- 

 wards the external depreflion in the ilium. But it is to be 

 remarked, that tJie fhortening and elongation are rarely pro- 

 duced, except by luxations of orbicular joints. However, 

 the abfence of thefe fymptoms in diflocations of the gingli- 

 moidal articulations is amply compenfated by the fuperficial 

 fituaiion of the bone ; a circumftance which renders it eafy 

 to afcertain their relative pofitions. 



The direction of the bone is changed, for the luxated end 

 cannot leave its natural place, without the other being thrown 

 into a contrary diredlion. Thus, in the luxation of the 

 luitnerus downwards and inwards, the pofition of the arm is 

 obliquely downwards and outwards, inftead of being ftraight 

 along the fide. This mode of judging of the occurrence of 

 a dillocation by the change in the direftion of the limb, is 

 much eafier in recent cafes, than in thofe which have con- 

 tinued for a coniiderable time. 



As ths fuuation and direction of a diflocated bone are 

 altered, it neceffarily follows that fome mufcles muft be pre- 

 ternaturally relaxed, while others are overftretched and 

 ftrained, as may be feen with refpedl to the deltoid mufcle, 

 in cafes of ],uxations of the humerus, which are the moft 

 frequent of all. This unequal tenfion and relaxation of muf- 

 cles may alfo afford lome alfiltance in forming the diagn »fis. 

 Time feems, however, fomething to remove, in a great 

 meafure, the alteration produced in the contour of a hmb, 

 by certain luxations ; and it is obferved that in old difloca- 

 tions of the humerus, the fulnefs of the Paoulder, juft below 

 the acromion, is in fome degree reftored. 



In thefe alterations of the natural fiiape of tlie limbs, we 

 are te comprehend the changed relations of the eminences of 

 a joint with refpeCl to each other ; the exiftence of projections 

 ill places, where there ought to be depreffions ; and of de- 

 prcffions where there ought to be eminences. Thus, in the 

 I'jxatiujj of tlie humerus inwards and downwards, a hard tu- 

 mour caiifed by the head of the bone itfelf, may be diftinftly 

 felt in the hollow of the axilla, while an unnatural depreffion 

 May be perceived jull under the acromion. 



Our hmbs, even when fraftured, as Boyer has obferved, 

 may be trade to perform feveral motions, and may be put 

 into various attitudes. In a cafe of a broken thigh, the 

 fur^con fnot, in truthr v.ithout caufing fcvere pain,) may, 

 by taking hold of the leg, move it round in a circular di- 

 se^lion, and, may point the foot inwards and outwards- 



But in luxations of the thigh, fuch motionB are altogctW 

 impoflible, before the bone is reduced. 



By a confideration of all thefe fymptoms, diflocations may 

 always be detefled. When the cafe is not afcertained within 

 a moderate tim.e, cither througli negligence or ignorance, it 

 is a ferious affair for the patient ; becaufe the inability of 

 ufing the limb is imputed to the contufvon, and the treatment 

 is regulated accordingly ; the bone, after a time, becomes 

 incapable of reduftion, and tlie lamenefs and deformity are 

 then irremediable. Such furgeons as are grofsly deficient in 

 anatomical knowledge, arc tlie moft liable to deliver wrong 

 opinions concerning diflocations ; for, not being able to judge 

 of the due relative diilanccs which ought to exift between 

 certain proceffes of the bones, they are not at all qualified to 

 decide whether many cafes are mere contulions, or whether 

 they are fraclures or diflocations. 



On the fubjedt of prognofis in cafes of diflocation, it is 

 remarked that luxations of the orbicular joints are much lefs 

 dangerous than thofe of the ginglimoidal articulations. As 

 the attion of the mufcles has a great fhare in producing the 

 iirll defcription of cafes, there is lefs violence done to the 

 external parts, and the foft parts are lefs lacerated. 



In all cafes the extent of the evil is in proportion to the 

 largenefs of the furfaces of the joint, the number and ftrength 

 of the furrounding mufcles, and the thicknefs and number 

 of the ligaments. Hence, luxations of the foot and knee are 

 more dangerous than thofe of the elbow and wrift ; the 

 former require a much greater degree of external violence 

 to produce them, and confcquently the foft parts are more 

 injured. 



Luxations of the orbicular joints are more difficult of re- 

 duftion than thofe of the ginglimoidal articulations, and dif- 

 locations of the hip are more troublefome to reduce than 

 luxations of the flioulder. Thefe circumftances are exph— 

 cable by the power and aftion of the mufcles, in refilling 

 the endeavours of the furgeon to bring the head of the bone 

 into its place again. 



But, perhaps, the thing which, of all others, tends mofl to 

 increafe the danger of a diflocation, is the accident being, 

 what is termed compound, that is, attended with an external 

 wound, communicating with the cavity of the luxated joint. 

 Many fuch cafes require immediate amputation. The pro- 

 priety of the operation depends, however, in a great mea- 

 fure on the extent of injury done to the foft parts. \^Tien 

 thefe have not been largely lacerated, torn, and contufed, the 

 furgeon fhould endeavour to fave the limb. Even the hazard 

 of a compound diflocation' very much depends on the kind of 

 joint affefted. Such injuries of the articidations of the 

 fingers or toes cannot be compared, in point of danger, with 

 fimilar accidents interefling the ankle, the knee, or the 

 elbow. 



Luxations arifing from difeafe of a joint, cannot in ge- 

 neral be reduced and cured like diflocations from external 

 violence ; for the ligaments and art ciilar furfaces are, in fail, 

 always more or lefs deftroyed. 'i'liis obfervation, however, 

 is not to be extended to hixations, induced by a mere loofe- 

 nefs of the ligaments. Thefe cafes indeed are very fubjeft 

 to recur; but they can eafily be reduced. Many difloca- 

 tions of the jaw are connrdted with a lax ftate of the liga- 

 ments, and afford an illuflration of the preceding remark. 



LalUy, the danger of diflocations in general is much in- 

 fluenced by the degree of contufion prefent, and by the in- 

 jury done to blood-veffels, or large nerves. The 'atter vio- 

 lence fometimes occafions a paralylis of tlie mufcles, to 

 which the injured nerves, fends its filaments. Boyer has feen 

 a paralyfis of the deltoid mufcle brought on by a violent con- 

 1\ tuHoa 



