LUXATION. 



any impiilfe on the radius, from below upward ? The im- 

 moveable relilling end of the humenu would then prevent 

 the radiu-i from quitting tlie capfular ligamctit. C;'.n the 

 accident arife from a violent extenfion or flexion of the fore- 

 arm ? Here, the whole force operating on the ulna, the 

 radius fcarcely feels the impulfe. 



Hence, accidental dlflocatious of the radius, f'uldonly pro- 

 duced by an external caufe, mu'.t, if they ever iiappen, be 

 exceedingly uncommon at its upper end. This is not the 

 cafe witli refpecl to fuch diflocations which occur flowly 

 lit this joint, efpecially in children, in whom the ligaments 

 become lax in confequence of repeated eiforts. With this 

 kind of cafe, we have here uothuig to do. 



Experience fometimes feems to militate againfc the above 

 refletlions. Duverney quotes fome ir.llances of diflocations 

 of the radius, fuddenly produced by external caufes. Some 

 other praditioners mention fimilar examples. But, in their 

 examinations, have thefe men paid all due attention ? An 

 analogous cafe has been tranfmitted to the French Academy 

 of Surgery, by one of its fallows ; but doubts have arifcn 

 concerning its reality, and there arc too few fafts for, and 

 too much prcfumptive evidence agaiuii, the truth of fuch 

 cafes to believe their e/.iitence. Default himlelf rejefted thuir 

 reality. 



Luxation of th: loivcr End cf the Radius. — The canfes are 

 the fame as tiiofe of all analogous cafes, i. Violent aflion 

 of the pronator and fnpinator mufclos. This is, donbtlefs, 

 a very unHfual caufe, for iJefault never knew an inilance of 

 it. 2. External force, moving the radius violently into a 

 Itate of pronation, and rupturing the back part of the cap- 

 fule ; or into a Hate of fupinalion, and breaking the front 

 part of the capfular ligament. 



Kence, there are two kinds of diflocation ; one forward, 

 the other backward. The Hrll is very frequent ; the fecond 

 ii much lefs fo. The latter cafe never prefented itfclf to 

 Default but once, in the dead body of a man who had 

 both his arms diflocated, and no particulars could be learnt. 

 The other cafe Occurred very often in the prattice cf this 

 eminent furgeon. Five examples have been publifticd. 

 Doubtlefs, this difference i> owing to all the principal mo- 

 tions of the radius being in the prone direction. 



This obfervation is" confirmed by the fact, that the lower 

 joint of the radius, in the dead fubjt.Cl;; may be diflociited as 

 eaiily by a fupine, as a prone motion of this bone. 



Tiie fymptonis of the luxation forward are : l. Conftant 

 pronation of the fore-arm. 2. An inability to perform fupi- 

 nation, and great pain on this being attempted. 3. An 

 iriiufudl prcjeclion at the back of the joint, in confeqncnce 

 of the protrullon of the little head of the ulna through the 

 capfule. 4. The pofition of the radius i-; more forward 

 than natural. 5. Conitant adduction of the thumb, which 

 alfo is almoft alway.'i extended. 6. A half-bent Rate cf the 

 fore-arm, and very often of the fingers. This, iiHced, is the 

 pofition which the fore-arm ufually affumes in all afted\ions 

 of its bones, and, in the prcfont inltance, tlie pollure can- 

 not be changed without confiderable pain. 7. More or lefs 

 fwelling around the joint. This fometimes comes on imme- 

 diately after the accident, but always afterwards, if the 

 reducUon ihould remain unaceompliilied. The condition of 

 the joint may thus be obfcured, and the accident uiittaken 

 lor a fprain ; as Default often obferved to have occurred 

 with furgeons, who had been called to thefe accidents bcfoi'e 

 him. The ferious confcquence of this miftake i?, that no 

 attempt at reduflion is made, and the articular furfices 

 having time to contraft adhefions, the diforder is frequently 

 rendered irremediable. 



A luxation cf the radius backward is charafterizcd by 



fymptoms the reverfe of thofe above-mentioned. They 

 are a violent fupination of the limb ; inability to put 

 it prone ; pain on making the attempt ; a tumour in front 

 of the fore-arm formed by the head of the ulna ; a pro- 

 jefti')!! backward of the large head of the radius ; and ab- 

 duclion of the thumb. 



RfduH'wii. — When the diflocation is forward, an afuttant is 

 to take hold of the elbow, railing the arm a little from the 

 body ; another is to take hold of the hand and fingers. 



The furgeon is to take hold of the end of the fore-arm 

 with both hij hands ; one applied to the infide, the other to 

 the outfide, in fuch a manner, that the two thumbs meet 

 each otlier before, between the ulna and radius, wiiile the 

 fingers are applied behind. He is then to endeavour to 

 feparate the two bonts from each other, pufliin^ tlie radius- 

 backward and outward, while the idna is held in its proper 

 place. At the fame time the afliftant, holding the hand, 

 fhould try to bring it into a Hate of fupination, and confe- 

 quently the radius, which is its fupport. Thus puflied, in 

 the dirediou oppofite that of the diflocation, by two powers, 

 the radius is moved outward, and the ulna returns into the 

 opening of the capfule, and into the figmoid cavity. 



If chance Ihould prefent a diflocation of the radius back- 

 ward, the fame kind of proceeding, executed in the oppofite 

 direction, would ferve to acccmpliih the reduftion. 



Luxation! of the iVr'ift. — The carpal bones maybe luxated' 

 from the lower ends of the radius and uhia forwards, back- 

 wards, inwards, or outwards. The two lirll; cafes, cfpecially 

 the one backwards, are the moft frequent. The diflocation 

 backwards is rendered eafy by the diredtion of the convex arti- 

 cular furfaces of the fcaphoidjfeniilunar, and pyramidal bones, 

 which floping more backwards than forwards, muH make 

 them more difpofed to flip in this diredlioii than any other. 

 The accident may be caufed by a fall on the back of the 

 hand, while much bent ; in which event the firff row of the 

 carpal bones flide backwards into the oblong cavity of the 

 radius, lacerate the pollerior ligament, and form an emi- 

 nence behind the lower ends of^the bones of the fore-arm. 

 This promircnce, the depreflion in front of tlie wrill, and 

 the extraordinary flexion of the hand, which cannot be 

 extended, are the charadlerillic figns of ttiis kind of diflo- 

 cation. 



The diflocation forwards generally arifes from a fall on 

 the palm, the fingers being extended, and more force ope- 

 rating on the lower than upper part of the palm. The 

 luxation is ieldom complete; and the hand remains pain- 

 fully extended. The great many tendons, which run before 

 the wrifl, and the annular ligament being puflied forward, 

 the prominence formed by the carpal banes, in front of the 

 ends of the radius and ulna, is not eafily deteded, and the 

 cafe may be miilaken for a fprain. 



Diflocations inwards, or outwards, are never complete. 

 The projection of the carpal bones at the inner or or-ter 

 fide of the ioint, and the diitortion of the hand, make luch 

 cafes fuflici.'iitly evident. 



All diflocations of the wrifl are very eafy of reduction. 

 For this purpofe, gentle extenfion n\ull be made, while the 

 two furfaces of the joint are made to flide on each other in 

 a direftion contrary to v/aat they took when the accident 

 occurred. 



Diflocations of the wrifl are always attended with a great 

 deal of fpraining of numerous tendons and laceration of li- 

 gaments, and CG-nfequently coiif.derable fwelling generally 

 follows, and the patient is a long time in regaining the per- 

 fetl ufe of the joint. To relieve the fymptoirs as much as 

 poffible, the be!l olan is to keep the hand and wrifl conti- 

 nually covered witii linen wet with the faturniiie lotion, and 



tc 



