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Show 161: or iiisLOCA'iios. ing against a flat surface, not rolling in its natural socket, But let us recollect, that there may be a roughness and im. peded motion in the joint, occasioned by inflammation having diminished the natural secretion of sinovia, where there is no degree of dislocation. Another diagnostic may be sometimes found in the pressure of the displaced head of the bone-I not only mean that we may sometimes discover the displaced head of the bone, but that the effect of its pressure on the neighbouring parts de~ clares to us its new position : as for example, when the head of the humerus, resting in the axilla, presses on the nerves, or artery, or causes numbness of the hand and arm, or weakness r~w~flfv o‘rgvflr«-.-a-3. N44 ,4‘ , 4‘3 . A A . ,‘nm‘t-‘S-‘f‘fi -" "War" mam in the pulse at the wrist. Before we attempt to reduce a dislocation it behovcs us. in a particular manner, to think of the position in which the patient stood, and the nature of the force which displaced the bone. It must be very evident, that the bone ought to be brought to the same position in which it received the has pulse which dislocated it, before it can be easily reduced. We shall find examples as we proceed, where the ligaments impede the reduction, owing to the neglect of this plain rule. The muscles too will always, in a certain degree, impede the reduction. On attending to the origins and insertions, or, in other words, to the action of the muscles, it is possible, by bending the joints, and relaxing the flexor muscles, to free the head of the bone from its confinement. It is a commonly re- ceived opinion, that the action of the muscles is not always direct against the elongation of the limb, but that they bind the heads of the dislocated bones together, so that the processes of the bones check into each other, and absolutely prevent any degree of direct force from disentangling these pro- DISLOCATION OF THE CLAVICLE. 16;) To reduce the shoulder joint, the chief difficulty is to secure the scapula; and the efforts to reduce the dislocated thigh bone are often ineffectual owing to the pelvis being left free, and only the other thigh secured. It is customary, and right, to fatigue the muscles of the limb before the full effort is made to reduce the bone. The tackle is pulled tight, and the force gradually increased ; the ' surgeon feels the progress of the head of the bone, and directs the efforts of the assistants; and by rolling the head of the bone, and sometimes by lateral pressure, (such as may serve to disentangle the processes of bones), he assists their efforts: or, when the bones have been brought as near to a correspondence as the direct pulling on the limb will affect, by a sudden effort he changes the angle of the joint, and with the power of the long bone, as a lever, reduces the dislocation. The marks of the reduction may be learned from what I have said of the signs of dislocation; or they may be summed up by saying that the limb is brought to its natural state, and the patient suddenly gains the power of complete motion. The bone will often return with a distinct and audible jirk into its place, such as might be expected from the smooth round head of the bone being drawn over the margin into the well-lubricated hollow of the socket. The free- dom from the painful and unequal extension of the muscles, makes the patient satisfied that the bone is reduced, before the surgeon can be aware of it. The mechanical power of the double pulley ought to be preferred to the force of many assistants, from its being so much more easily managed and directed. But let it be remembered, that the surgeon may make a misealculation of this mechanical increase of power very hurtful to the patient. cesses, or stretching the limb. Next in importance to the relaxation of the muscles, and DISLOCATION OF THE CLAVICLE. the due direction of the shaft of the dislocated bone, is the providing of proper laques ; but especially applying them well, and to their proper place. The two bones, whose sur~ ALTHOUGH the clavicle be united to the sternum by strong ligaments, yet it is a weak joint, seeing that it is small to faces are dislocated, must, if possible, receive the Whole force. .bear the weight, and allow the free motion of the upper er: I flight-WA -..3- m, _ N"? .,.. W . vmm ‘ I in |