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Show 180 mementos: or THE ELBOW. mszocuron or The snow. tive comparison, that it may be decided on which side the su. periority lies. I hope the question is easily decided ; when the surgeon pulls the arm at a right angle with the body, and at the same time pushes back the lower angle of the scapula, he brings the bones into that position which relaxes the remaining connexions of the joint, and relieves the check which impeded the reduction. The truth is, I believe, that we cannot throw back the acromion, but in as much as we can we prevent the reduction in difficult cases, unless we at the same time elevate the arm bone. From considering the position of the head of the humerus, and effect of the ligament, and the position of the two great processes of the scapula, it appears to me, that the motion to be employed completely to relax the ligament, and move the head of the humerus over the brim of the glenoid cavity, is this, let the arm be extended until the head of the humerus is felt to be drawn from the hollow of the axilla ; the arm is then to be raised and moved in a circular direction towards the side of the patient's face. In this movement the neck of the humerus first bears on the acromion, and then on the cora= coid process of the scapula ; against the last process the lesser tubercle of the humerus bears so, that with the lever power of the humerus its articulating head is raised over the edge of the glenoid cavity, and slips into its place. [J'F‘WZ‘ ~‘rgtam', .‘ww .- o-‘d-«z. .... -< a" . ‘ DISLOCA'IIO‘S OF THE ELBOW". THE dislocation of the ulna from its connexion with the lower end of the humerus happens in young people chiefly, in whom the coronoid process of the ulna is not so complete a guard to the joint as it becomes in the adult. A person who running falls on his hands and wrist may dislocate the ulna, because the whole weight and shock is received on the elbow joint, in the line of the ulna ; and in this direction the coronoid process is the sole guard against dislocation. The ulna starts backward, and the olecranon and articulating part of the ulna is thrown out behind the arm bone. The promis 18] Hence of the olecranon behind the joint, and the painful rigid-'ity of the arm, sufficiently distinguish the nature of the ach dent. I need scarcely add, that so firm is the union of the radius with the ulna, that both bones are dislocated when the ulna is felt thus out of place. To reduce the dislocation of the ulna, the surgeon bends the arm; he puts a handkerchief round the patient's arm, and gives it to an assistant to hold, who stands behind ;, then with the left hand he takes hold of the arm, and with the palm of the right hand on the olecranon, he endeavours, by pushing, to restore the bone to its place. An assistant may facilitate the reduction by taking hold and pulling by the wrist, and gently bending the arm at the same time. However, this will not always do, and a coarser and more dangerous means has been used. The surgeon has been forced to grasp the arm with one hand, and the wrist with another, and then thrust his knee into the fore part of the elbow joint ; and by this means bend the joint and reduce the dislocation. It will be observed, that the difficulty of reduction proceeds from the coronoid process of the ulna checking into the posterior fossa of the humerus, and this operation by bending, and at the same time pulling separate the bones, is the most efi'ectual way of reducing the dislocation. It would, however, be a very terrible accident during this operation, to find that we had separated the apophysis, which may certainly happen in a child ! SUBLUXATION OF THE ELBOW' JOINT. THE subluxation of the elbow joint is when the segmoid cavity of the ulna is forced laterally, and passes over the pro- minent part of the trochlea of the humerus ; the articulating surface of the ulna sits in that part of the humerus appropriated to the head of the radius. The nature of the accident is ascertained by the circum- stance of the great increase of the space betwixt the inner con- wwwwui ' wom MOSS? |