Fig. 62.—The Clove-hitch knot.
Reduction by simple extension.—The patient again lies flat on his back, a jack towel is passed round his body and fastened behind the opposite shoulder for counter-extension, while a second towel is attached to the wrist by a clove hitch and intrusted to two or three assistants, who are desired to pull quietly and steadily directly away from the patient’s body. The surgeon meanwhile watches the progress of the extension, altering its direction as he finds the head more or less engaged against the scapula, and finally with his hands thrusts the head into its socket. Sometimes there is much difficulty in getting the head back to the glenoid fossa, even when the humerus is completely disengaged from the scapula; this difficulty is often overcome if an assistant rotates the humerus backwards and forwards, while the extension at the wrist and the pressure on the head of the humerus is steadily maintained. When the limb is replaced it is fixed to the side as before directed.
Fig. 63.—Dislocation of the shoulder reduced by simple extension.
If the dislocation has existed more than a few hours, relaxation of the muscles by chloroform and extension of the limb carried directly away from the body are more sure of success than the heel in the axilla, because they allow greater power to be exerted in a steadier manner than is possible by the other mode.
The Elbow.—The signs of dislocation at this joint are tolerably evident, but there is often coexistent fracture of the coronoid or olecranon processes. Separation of the articulating surfaces of the humerus from the shaft is sometimes mistaken for dislocation of the forearm backwards.
In dislocation of both bones backwards the olecranon is very plainly felt behind the lower end of the humerus; the sigmoid notch is generally to be made out, and the forearm is fixed at a right angle. The altered relation of the olecranon to the condyles suffices to distinguish dislocation from fracture of the humerus at its lower end, where the olecranon also goes backwards, but the condyles go with it. The immobility of the joint distinguishes it from separation of the lower articular surfaces of the humerus from the shaft, an accident, moreover, only met with in children.
Other subordinate distinctions between dislocation and fracture are, the limited movement, the difficulty of restoring the bones to their natural position, and the absence of crepitus; lastly, the peculiar form of the articular surfaces can sometimes be made out.
In reducing the backward dislocations the patient sits on a chair on which the surgeon rests his foot, pressing his knee against the forearm at the elbow for a fulcrum; then, grasping the wrist with one hand, and steadying the arm with the other, he flexes the elbow to dislodge the coronoid process from the fossa at the back of the humerus; when this is done, the articulating surfaces slip into place. This plan is commonly adopted when the olecranon is displaced, but if it fails to reduce the dislocation, direct extension at the wrist must be employed, as for the following dislocation.