the action of the triceps muscle. An exception is formed by the other supracondylar oblique fractures, the flexionfractures of Kocher (Fig. 76), in which the course of the line of fracture is such that posterior displacement of the lower end of the fragment is impossible. The sharp end of the shaft of the humerus in these fractures is displaced backward and sometimes enters the triceps muscle, whereas in the so-called extension-fractures it is displaced forward and may penetrate the brachialis anticus.

An important step in the examination consists in seiz

Fig. 75.-Diagram of extension-fracture (Kocher); the direction of the line of fracture is from behind and above, forward and downward.

Fig. 76.-Diagram of a flexionfracture (Kocher); the direction of the line of fracture is from before and above, backward and downward.

ing the lower end of the humerus by the condylar prominences, which are readily felt, and attempting to elicit abnormal mobility with the shaft. A fracture at the lower end of the humerus may also be recognized by fixing the arm and pushing the forearm against it. If a fracture is present, crepitus and abnormal mobility will be discovered. The forearm also presents a certain mobility, both for abduction and for adduction. The position of the olecranon with respect to the condyles is normal; not in

frequently the fragments can be directly felt. Reduction is effected by simple extension with the elbow in flexion,

Fig. 77.-Old, supracondylar extension-fracture, with the same deformity as in dislocation.

Skiagraph.

Ludwig Maack, ten years old, was injured by a fall three months before admission. An obtuse-angled contracture of the joint, marked osteoplastic thickening at the lower end of the humerus, and paralysis of the musculospiral were present. The skiagraph shows the posterior displacement of the lower fragment; the lower end of the diaphysis interferes with flexion. Operation: The musculospiral nerve was dissected out and found to be completely divided, the two ends grown fast to the bone and cicatricial tissue; the nerve was repaired by a suture, and the lower end of the shaft of the humerus was removed, whereupon flexion at once became possible almost as much as in the normal limb. Result: Improved motion at the elbow after a long course of exercises; the paralysis of the musculospiral nerve did not disappear.

but the deformity tends to return when the extending force is removed.

Treatment. Complete reduction, if necessary under anesthesia, and fixation by means of splints or padded tin gutters applied to both the outer and the inner side of the limb. The arm is fixed with the elbow either in extension or in flexion, in whichever position retention is most effectually obtained. In adults an adhesive plaster dressing with permanent extension by means of weights may be used. The arm is placed in extension with the forearm and hand on a sliding rest; the hand should be posed and in supination. Lateral loops or sandbags may be necessary to effect counterextension or pressure. children a splint dressing is all that is necessary. The

ex

In

wire splints recommended for fractures of the shaft of the humerus and illustrated on page 167 may be used (see also Fig. 67, page 167). The importance of careful reduction and constant supervision cannot be emphasized too strongly. I am in the habit of anesthetizing the children, not only at the first dressing, but in some cases also at subsequent dressings. The dressing should be changed at short intervals. Passive movements, massage, etc., must be begun early. Improper treatment may result in union with outward (varus) or inward (valgus) deformity of the limb (Plate 37).

[The position of the forearm, flexion or extension, is a