LUXATION. 



fhoulder, after bcinp drawn outwards, muft be carried back- 

 wards ; or upwards, when the diflocation is in the fame 

 direftion. By obferving thefc rules, the head of the bone 

 mav be replaced, with the aid of a liltlc prclTure of the 

 thumb. But ihoujrh the reduction may be eafy, it is dif- 

 ficult to maintain it, all the ligaments being torn, and the 

 articular furfaces difpofcd to (lide away from each other, on 

 rtie flightelt motion of the fhoulder. 



The apparatus ufcd by Default for fractures of the cla- 

 vicle is to be employed in luxations of the iternal end of the 

 bone. (See Fractures of the Clavicle, and Surgical Plate IV.) 

 The flioulder continues to be kept outwards by means of the 

 eufhion placed in the axilla ; but notwithftanding the ut- 

 moft attention ou the part of the furgeon, the head of the 

 clavicle cannot be prevented from being fomewhat nrore pro- 

 minent than that of the oppofite fide. Brafdon propoft-d 

 a tourniquet for making prefiiirc on the luxated extremity of 

 the bone, with a view of hindering fuch deformity, though, 

 according to Boyer, it will not anfwer the purpofe. 



Luxations of the Scapulary End of the Clavicle. — Thefe 

 cafes are much Icfs frequent than the former, owing to the 

 very great ftrcngth of the ligaments binding the clavicle to 

 the fcaptila. The fcapulary end of the clavicle is feldom lux- 

 ated in any direftion except upwards. Boyer admits the pofli- 

 bility of the accident taking place downwards, and we think 

 ■we have feen an inftance, in which it was caufed by a heavy 

 brick falling on the flioulder from a confiderable height. 

 There was no crepitus, and the end of the bone, which 

 was moveable, was obvioufly depreffed below the acro- 

 mion. 



The diflocation upwards is that, which principally de- 

 mands the attention of tb.e praftitioner. It may be caufed 

 by falls, in which the violence operates on the extremity 

 of the fhoulder. The fcapulary end of the bone flips up- 

 vards over the acromion, which laft procefs is itfelf a little 

 drawn under the luxated pari of the clavicle, when the 

 fhoulder is pulled inwards by fuch mufclcs, as have the 

 effect of bringing the arm towards the trunk. The writer 

 of this article was lately ccnfnlted in a very manifeft cafe 

 of diflocation of thf fcap'jlary end of the clavicle. The 

 patient was a young gentleman out of Yorkfhire, where 

 the accident had happened, and, not being underitood, was" 

 left unreduced. When the cafe was brought to us, it was 

 too late for any affiftance to be rendered. Fortunately, 

 the inconveniences fuffered were nof very great. The pa- 

 tient generally inclined his head towards the affefted fhoul- 

 der, and experienced a degree of weaknefs in raifing his 

 arm to his head ; but even thefe infirmities viere gradually 

 becoming Ws. 



Boyer conceives, that a violent action of the trapezius muf- 

 fle, which we know is attached to the outer half of the 

 clavicle, rfay have a fhare in producing this kind of difloca- 

 lion, efpecially if the mufcle fnould forcibly con'raftjuft at 

 the moment when the acromion is fixed on the ground or 

 body, againft which it falls. 



The diagnofis of the accident cannot be very difGcult, 

 fmce the end of the clavicle may always be diflinflly felt, 

 forming a projedlion under the fliin that covers the acromion. 

 The head is inc'ined to the aflefted fide, and the pa- 

 tient avoids moving the arm, in confcnuence of fuJi adtion 

 occafioning pain. 



The diflocation is to be reduced by drawing the arm 

 and fhoulder outwards, and pufhing- the difplaced end of 

 the clavicle downwards. Default's apparatus for broken 

 collar bones is then to be applied. (See FraSwe of tie 

 Clavicle, and Plate IV.) The eulhion in the arm-pit, when 



the elbow is confined neaf the fide with the roller, here 

 acts very ufcfully in keeping the flioulder outwards. The 

 turns of the bandage, which go from the elbow to the 

 fhnulder, fliould alfo be made to aft efpecially on the outer 

 end of the clavicle, fo as to prefs it downwards. 



Luxations of the Shoulder; or of the Humerus, or Os 

 Brachii, from the Scapula. — The flioulder joint allows the 

 arm to be moved in every poflible direftion, and as tht 

 ftrufture, cflential to fo great a latitude of motion, hinders 

 the articulation from being endued with the flrength and 

 ffabihty of other lefs moveable joints, it becomes, of courfe, 

 a very prc-difpoling caiife of diflocatious. In faft, no joint 

 is fo frequently luxated as the fhoulder. And it appears 

 from a comparative regifter, kept at the Hotel Dicu at 

 Paris, that, during feveral years diflocations of this articu- 

 lation equalled in number the lux.itions of all the other 

 juints together. QLuvres de Default par Bichat, tonr. i, 



P- 341- 



Every thing, fays tie author of the preceding work, 



appears to facilita.e the efcape of the bone from its natural 

 cavity, i. In the articular furfaces, a fliallow oval cavity, 

 which receives a femi-fpherical head twice as cxtcnfive as 

 itfelf in the perpendicular direction and thrice 'as broad 

 from before backwards, 2. The only ligament, ftrengthen- ' 

 ing this joint, is a mere capfule, which is thin below, the 

 very direftion in which there is nothing to oppofe a luxa- 

 tion, and thicker above, where the acromion and coracoid 

 proccfles, together with the triangular ligament, form an 

 almoft infurmountable obftacle to fuch an accident. 3. With 

 refpcft to the mufcles and motions of the flioulder, we have 

 to notice numerous and itrong fafciculi around the joint, 

 communicating to it movements eafily performed in every 

 direftion ; propelling the he&A of the humerus againfl: dif- 

 ferent points of the capfule ; and rupturing the latter part, 

 when their power is fuperior to its refiflance. 4. As for ex- 

 ternal force, what bone is more expofed to its effefts, par- 

 ticularly in the labouring claffes of fociety ? 



Affeited by fo many different pre-difpofing caufcs, the 

 humerus would be inceffantly fnbjedted to diflocations, did 

 not the fcapula, which is equally moveable, follow <fll its 

 motions, and afford it a point of fupport differently dif- 

 pofed, according to the different pofition of its upper end; 

 In fhort, much of the ftrength of the joint depends upon the 

 double moveablenefs of the two articul.ir furfaces. 



Of the different Kinds of Luxations of the Shoulder.^ 

 Though this joint is generally much difpofed to luxations, 

 it is not equally fo at every point. There are fome points 

 at which the accident cannot happen at all ; while there are 

 others at which, though it feems pofilble, it has never 

 been obferved. Hence, before examining the mechanifm 

 of diflocations of the fhoulder, Default endeavours to de- 

 termine with precifion the direftions in which the accident 

 is poflible. He adverts to the confufion exifting among 

 writers on this fubjeft ; fome of whom employ different 

 terms to exprefs the fame thing ; while others have affixed 

 fimilar names to things which are eflentially diflerent and 

 diftinft from each other. With regard to fome kinds of 

 luxations they all coincide ; concerning others, they dif- 

 agree ! Default fiifl divides luxations of the humerus into 

 two kinds ; viz. primitive, wh.ioh are the fudden effect of 

 external violence, and confecutive, which fucceed the former 

 from caufcs hereafter to be explained. 



The fame eminent fnrgeon then dircfts us to fuppofe the 

 oval furface of the glenoid cavity to have four ftraight 

 lines drawn at its fides, in the form of a parallelogram ; 

 one reprefenting the upper edge of that cavity ; another, 



the 



