121. Mr. Luke performs the operation by two flaps on the same principle as in the thigh. There is a close resemblance in the manner of amputating the arm by the double-flap operation to that adopted for the amputation of the thigh. The first flap is made posteriorly to the bone, by transfixing the limb, for which purpose the knife is entered at the mid-point between the anterior and posterior surfaces, carried transversely across the limb, and made to cut toward the posterior surface, in an oblique direction, until all the soft structures are divided. It is necessary, in entering the knife, to bear in mind that the bone lies opposite to the mid-point, and that, in carrying the knife across the limb, it would strike against the surface of the bone, unless means were adopted for its prevention. This is easily done by grasping the structures which are to form the posterior flap between the fingers and thumb of the left hand, and by drawing them backward during the time the knife is entering at the mid-point and being carried across the limb. Having formed the posterior flap, the anterior one is formed as in amputation of the thigh, by cutting inward from the surface toward the bone with a sweep, which will make this flap equal in length to the posterior. The operation is completed by dividing the remaining soft parts by means of a cut carried circularly around the bone, and by sawing the bone in the line of division. The after-treatment is the same as in the thigh.
122. _Excision of the elbow-joint._--An incised wound of moderate extent into the elbow-joint, cutting off with it a part of the condyle of the humerus, or the head of the radius, or a part of the ulna, demands the removal of the injured piece of bone only. The forearm should be bent, and the antiphlogistic treatment fully carried out. A ball fracturing the olecranon, or other portion of a single bone, although opening into the joint, does not immediately require any operation.
If a ball should lodge in the lower part of the humerus, or in either of its condyles, it should be removed as quickly as possible by the trephine, or other appropriate instrument.
When the articulating ends of the humerus, radius, and ulna are wholly or in part injured by a musket-ball, it was formerly the custom to amputate the arm in such instances of great mischief--an operation which should be superseded by that of excision of the joint, by which the forearm will be saved, and considerable use of it retained.