A straight incision is made over the point of the olecranon a little internal to its middle. The upper portion of this incision splits the triceps. Its lower part is carried down to the bone on the posterior surface of the ulna. The attachment of the triceps to the inner side is then dissected off and the ulnar nerve raised from its groove without injuring it. The medial (internal) condyle is then to be cleared of the muscles attached to it. The parts external to the incision are now to be raised. By means of periosteal elevators aided by the knife the external part of the triceps is detached from the bone as closely as possible, following exactly the edge of the ulna. The anconeus is raised with the triceps and the broad fibrous expansion passing from the olecranon to the lateral (external) condyle and thence over the anconeus to be continuous with the deep fascia is preserved intact. On the care with which this is done depends the amount of subsequent muscular control. As the triceps is turned aside the muscles attached to the lateral condyle are raised in the same manner. The soft parts being drawn to each side the bones are protruded and the remaining soft parts anteriorly can be detached. A flat spatula is then passed beneath the bones and the humerus sawed through opposite the upper edge of the medial (internal) condyle above and the radius and ulna opposite the lower edge of the head of the radius below. The insertions of the biceps and brachialis anticus are not disturbed.

Fig. 316.   Resection of the elbow joint; the ends of the bones are exposed ready to be removed.

Fig. 316. - Resection of the elbow-joint; the ends of the bones are exposed ready to be removed.

In raising the supinator (brevis) from the upper portion or the radius care should be exercised not to wound the posterior interosseous nerve. It runs between two planes of muscular fibres in the substance of the supinator (brevis). It is a nerve of motion supplying all the extensor muscles with the exception of the anconeus, brachioradialis (supinator longus), and extensor carpi radialis longior; hence its injury will be followed by serious paralysis. Almost no vessels require ligation (Fig. 316).