LUXATION. 



moved fo far from the acetabulum but in very few cafes, and 

 thnt it only advances near tlie ilio-poClinsal eminence. De- 

 faiilt met with a luxation of lliis kind in a porter of the flour- 

 market ; his foot flipped, and the le^ and thigh were carried 

 backwards, whllft a heavy burden was placed on his fhould- 

 ers. His body was bent backwards, and the head of the 

 femur, direAed forwards and upwards, burft its capfule 

 and triangular ligament, and pafled under the crural arch 

 into the fold of the groin, where it was eafily felt through 

 the integ'ments. 



The whole extremity is turned outwards in this luxation ; 

 it is alfo fliorcened. The great trochanter, brought nearer 

 the anterior and fuperior fpinous procefs of the os ilium, is 

 placed before that eminence ; that part into which the pfoas 

 and iliacus niufcles are inferted is railed up, and a tumour is 

 formed by the head of the femur in the fold of the groin, 

 which comprefles more or leis the crural nerves placed at 

 the external fide of the velTels of this name, and occafions 

 dull pains, with numbnefs and oven paralyfis, when the con- 

 tufion has been very great ; the knee, turned outwards, is 

 alfo ca-ried backwards. This fymptom is particularly re- 

 markable Ihortly after the accident has taken place ; for if 

 the diflocation has continued fome days, the thigh may re- 

 affume its natural direftion, and perform even gentle rotatory 

 motions inwards, the direflion outwards ftill continuing. 

 It is proper to remark, with refpeft to the tumour formed 

 by the head of the tcmur in the groin, that the pfoas and 

 iliacus mufcles may, in fraftures of the femur immediately 

 under the little trochanter, bring forwards the luperior por- 

 tion of this bone, caufe it to projedl in the groin, and form 

 an eminence there which might impofe on us, if we were not 

 apprized of the poffibihty of fuch an event taking phice. 



This luxation is particularly dangerous, as it requires a 

 combination of violent efforts to produce it, and as it necef- 

 farily muft be accompanied with great contufion and lacera- 

 tions. Neverthelefs, in the cafe treated by Default, the 

 redaftion, though difficult, was not followed by any ferious 

 accident ; and the patient, at the end of fifteen days, had 

 almoft entirely recovered the flrength and ufe of his limb. 



The procefs for reducing it does not differ from that 

 pointed out for the others. 



Luxation of the femur downwards ar.d backwards may, 

 like that of the humerus inwards and forwards, be either 

 primary or fecondary. It is primary, when, in confequence 

 of fome effort, the head of the femur is forced from the 

 acetabulum at its inferior and pofterisr part, and is placed 

 at the junclion of the os ilium and ifchium ; it is fecondary, 

 when it fucceeds to the luxation upwards and outwards, the 

 head of the femur, which was placed at firll in the external 

 ihac fofTa Hiding downwards and backwards, its paffage in 

 this direftion being favoured by the bending of the thigh on 

 the pelvis. 



In thefe two cafes, the head of the femur reds againfl; 

 that part of the ofia innominata where the os ihum and 

 ifchium join. The mufcles which cover the pofterior part 

 of the articulation, fuch as the pyriformis, gemilii, obtura- 

 tores, and quadratus femoris, are raifed up and llrctched ; 

 the pfoas magnus and iliacus internus -are in a great Hate of 

 tenlion, and this explains the turning of the limb outwards. 

 When this luxation is primary, the extremity is lengthened ; 

 a hard tumour is f^lt at the pollerior and inferior part of 

 the thigh s the great trochanter, by defcending, is removed 

 farther from the fpinc of the os ilium, and the knee and 

 fole of ihe foot are turned outwards; but if it be fecondary, 

 the thigh is much bent againfl the pelvis ; the knee and 

 fole of the foot are turned inwards, bccaufe the primary 

 luxation has been upwards and outwards. Secyndary lui- 



ation in this direftion is much more frequent than the pri- 

 mary ; in reducing it the fame rules are to be obferved af in 



other fpecies of luxations. 



Whatever may be the fpecies of luxation, we fhould 

 always be certain that it is perfeftly reduced before leaving 

 the patient. To afcertain this, we ought to move the thigh 

 in various direftions, taking care at the fame time to omit 

 that motion which might reproduce the luxation. 



When a luxation of the femur upwards and outwards has 

 not been reduced, the thigh remains fhort, and becomes 

 fliorter every day, until the head of the femur has made for 

 itlelf a kind of articular ca%nty in the fucfacc of the external 

 ihac fofla. The acetabulum leffens in fizc, or is entirely ob- 

 literated. The glut:£us minimus is emaciated, and ferves a». 

 an orbicular ligament to the new articulation. The head 

 of the femur lof'es its fpherical figure, is forced backwards, 

 and its neck becomes fhorter ; tlie perfon is lame, and walka 

 on the point of the foot. If the luxation ij downwards- 

 and inwards, the foramen ovale becomes the new articulating 

 cavity ; the obturator externus, raifed and pufhed inwards 

 by the head of the femur, becomes emaciated and ligament- 

 ous, and it and the glutsus minimus even fometimes offifv. 

 The lamenefs arifes in this cafe from the excefs of leno-th 

 of the difeafed Umb, which always diminifhes in fize, in con- 

 fequence of the mufcles not being fufficiently exercifed, oc 

 their aftion being impeded. 



Luxations of the PaUlla, or Knee-pan It is impofTible fbr 



the patella to be diflocated downwards without the tendoa 

 of the extenfor mufcles of the leg being firil ruptured ; nor 

 upwards, unlefs the hgament of the patella is broken. Iq 

 this laft cafe the extenfor mufcles may draw the bone more 

 or lefs upwards towards the groin. 



Diflocatioi.s inwards, or outwards, may happen with- 

 out other mifchief. They occur when the patella is vio- 

 lently pulhed in one of thefe direftions. According to 

 Boyer, great relaxation of the inferior hgament of the pa- 

 tella may create a predifpofition to tlie accident. Such, 

 fays he, was the cafe of the young man, whofe patcllas were 

 luxated outwards by the flightefi motion of the knees, as- 

 related by Hard in the Journ. de, Med. 



The diflocation outwards is the moil common. This- 

 may depend partly on the internal edge of the patella pro- 

 jefting more than the external one, and, therefore, being 

 more expofcd to violence? and partly, on the outer condyle 

 of the thigh-bone allowing the patella to flip over it with 

 facility. 



Boyer obferves, that the external condyle of the femur, 

 which is naturally more eminent anteriorly than the inner 

 one, may be depreffed, and this depreflion, from whatever 

 caufe it may proceed, favours the diflocation outwards. 

 He tells us that he has feen, among the military confcripts, 

 three cafes of luxation of the left patella outwards from. 

 fuch a caufe. In tliefe three individuals the patella was 

 placed at the outfide of the condyle, though not altogether 

 away from it. The anterior furface of the bone was turned 

 outwards ; the poflerior one inwards ; the internal edge was 

 placed anteriorly, and projected under the fl<in, while the' 

 external edge was direfted backwards. In all thefe in- 

 ftances the luxation had taken place during infancy. Bt 

 relaiung the extenfors of the leg, and bending the thigh, the 

 patella could eafily be replaced ; but unlets confined in its, 

 proper fituation, it was foon diflocated again. 



Another cafe is recorded by the fame writer, where a 

 luxation of the patcUa outwards followed a gunfliot-wound 

 in the vicinity of the knee. 



Luxations outwards, produced by external violence, are 

 rarely complete, as luch an accident could only arife from a 



degree 



