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Show 184i DISLOCATION or run THUMB. DISLOCATION OF THE THUMB. From-the same cause there is a difficulty to be encountered in the reduction of the thumb, and of the fingers! But the bones of the thumb being shorter and. thicker, and the ligaments of the joints stronger, it is only in the dislocation of the thumb that we have remarkable examples of the ineffectual violence used in the attempt at reduction. To REDUCE A DISLOCATION or A FINGER, we must not pull directly on the end of the finger; for that will be found to fix the bones by their own ligaments, so that they cannot come into their place. It is by grasping the finger forcibly, and bending it, that we shall succeed in bringing the heads of the bones into their natural relations. Thus far I speak from experience, but as to the disloca tion of the thumb I must reason from the anatomy, for it has not been my fortune to reduce a dislocated thumb. lflfihfivlrom We find, that in the attempt to reduce the first joint of A the thumb, the second phalanx has been torn off; this should convince us that the difliculty proceeds from the ligaments; for the muscles of the thumb could not hear such a degree of violence. When we have recourse to the anatomy we find, that the bones are united by a proper hinge joint ; that there are strong lateral ligaments ; and that the articulating heads of the bones are square, and have somewhat of a wedge form. Mr. Hey, taking these circumstances into consideration, has been led to the conclusion, that the difliculty of reduction proceeds from the head of the bone being pushed between the ligaments, in which situation the ligaments bind the bones together, and retain them locked. I should have expected that Mr. l-Iey would have followed up o . must bend the thumb at the dislocated joint, so as to carry the head of the bone which is dislocated in a semicircular movement round the articulating head of the metacarpal bone, before we can expect it to be brought through the two lateral ligaments. ‘ r,_p~l~‘"§:¢ -5" lam-fun'fic u Ma. - - K" these observations with the rule of practice, viz. that we I shall suppose that A is the metacarpal bone of the thumb; B is the first bone of the thumb dislocated from the metacarpal bone; and C is the lateral ligament. Now let us suppose that the bitch is put over the thumb at B, and that it is drawn in the direction of the line D D. It must follow, that the point E will rise to D, and the heads of the bones be consequently locked at F. To reduce the dislocation without lacerating the lateral ligament, it is evident that the dislocated head of the bone must be moved in the circular dotted line, which is the ex- act reverse of its motion when dislocated. I have a conviction, though I cannot give the proof, that by attending to the principle laid down here, the dislocat- ed thumb may always be reduced. But should it be otherways, should a case occur where many ineli‘ectual endeavours have been made, and the patient resists all further vi- olence, so thoroughly am I convinced that the difficulty proceeds from the lateral ligaments embracing the head of the bone, that I would insinuate the couching needle under the skin (obliquely), and cut one of the lateral ligaments, when I think there would occur no further difficulty in reducing the bone. After this the joint would require to be Eupported by a small splint and bandage. This is a mere opinion,-a proposition to stand contrasted with the alternaiive of the thumb remaining unreduced and lame. "n Juan‘lwwws" W. M95" |