excursion (destroyed by the luxation) by means of external pressure and traction, it immediately returns to its abnormal position as soon as the pressure is removed. The last-mentioned symptom is the most important one in the differential diagnosis between dislocation and fracture, as this tendency to return to the abnormal position is absent in fracture of a joint. There are other important symptoms in dislocation, such as the absence of the normal prominence of the bone, the ability to feel the articular extremity in an abnormal position, and the altered direction of the long axis of the bone. Mensuration is sometimes useful, as some dislocations are characterized by lengthening instead of shortening of the affected extremity.

As in fractures, so in dislocations, there may be additional injuries-injuries to nerves and blood-vessels, or extensive laceration of the soft parts surrounding the joint. Even the outer skin may be injured, lending to the injury the character of a compound dislocation; in such cases the treatment must be carried out according to strict aseptic principles.

[Compound dislocations without fracture are rare. The results, however, from proper treatment instituted early after the injury are excellent. The wound should be thoroughly irrigated with 1:1000 bichlorid, and loose pieces of tissue cut away. In many instances the capsule of the joint can be sutured and the wound closed without drainage. If later the joint becomes distended with effusion it should be aspirated. The introduction of gauze and drainage-tubes into the joint should be condemned. They irritate the synovial sac and increase the danger of subsequent ankylosis. If drainage is indicated, a small piece of rubber tissue answers the purpose best. In the majority of cases it is better, however, to close the joint capsule at once, and if indicated drain only the superficial wound. I believe that improper drainage in joint injuries is more frequently the cause of secondary infection and restricted motion than the injury itself.-ED.]

The diagnosis is sometimes very difficult when the dislocation is complicated by a fracture. This rare complication is usually produced by the external force continuing to act after the luxation has been produced.

The treatment has for its object the restoration or replacement of the dislocated bone (reduction). While it was formerly customary to employ great force in the reduction of a dislocation,-a proceeding which was not infrequently followed by grave consequences, such as the laceration of large vessels and nerves and the fracture of bones, the general practice nowadays is to effect reduction by manipulations based on a careful study of the anatomic relations and without the use of great force— generally under anesthesia. The rule that the reduction must be accomplished by forcing the dislocated extremity over the same path which it followed in the production of the dislocation is in the main correct. The manipulations should not be determined by thumb rule, but by accurate knowledge of the position of the articular head, of the tear in the capsule, and of the surrounding soft parts. "Our therapeutic actions nowadays are determined primarily by the anatomy of the dislocation" (Krönlein).

Successful reduction is recognized by feeling the bone glide back into place, and observing that the normal outline of the articular region and the normal mobility of the joint have been restored, while the tendency to return to the abnormal position has disappeared.

With regard to the subsequent course, after reduction, the following points may be of some importance. Under normal conditions, if rest has been secured by appropriate dressings, the tear in the capsule heals, the extravasation of blood disappears, and the slight synovitis which is the expression of irritation in the joint subsides in from one to two weeks. As soon as possible, even before the end of this period, massage and careful passive movements can and ought to be instituted. If, as occasionally happens, pain and symptoms of articular irritation return, massage must

be discontinued or at least performed with great gentleness. After the third week the excursions are to be increased and active exercises with the use of apparatus indicated. Eventually a complete restoration of function should be aimed at.

[The after-treatment of a dislocation is quite as important as that of a fracture. It must be remembered that besides the tear in the capsule other important ligaments may be stretched or torn. The proper healing of these fibrous structures takes a number of weeks, and during this time the joint, although it may be used to a certain extent, should have some form of support. If this is neglected, a permanent disability in the form of a weak joint or a tendency to recurrent dislocations from slight trauma may result. Hasevrock 1 has called attention to the necessity of this longer support, and describes and illustrates a number of simple apparatus which not only give support, but allow certain motions of the joint.-ED.]

The term habitual dislocation is used to designate the frequent recurrence of a dislocation, often under the influence of quite inconsiderable force. The patients are perfectly aware of their condition and usually have their diagnosis ready when they consult the physician; not a few are able to reduce the dislocation themselves. The cause of habitual dislocation is usually to be sought in extensive injury of the joint leaving an abnormally broad insertion of the capsule. For the treatment, such measures as prolonged immobilization and the injection of alcohol to produce shrinking of the tissues have been recommended. In very bad cases resection has been performed. It might be wise to try arthrotomy and partial extirpation of the capsule.

[I do not believe that injections of alcohol or any other substance should be used. Prolonged fixation should be first given a trial with the form of apparatus recom

1 Münchener med. Wochenschrift, 1899, vol. XLVI, p. 93; reviewed in Progressive Medicine, December, 1900, p. 168.

mended by Hasevroek, which allows some joint motion. If this fails, exploratory arthrotomy should be performed. In some cases the cause will be found to be quite simple, such as a loose cartilage, or a stretched or torn ligament. The cartilage should be removed and the ligament fixed by suture. Other cases will be more complicated. The condition, however, must be rare, because there is little in the literature on the subject, and even in a large surgical experience one observes these cases very infrequently.— ED.]

Under certain circumstances a dislocation may be irreducible. It may happen that, in spite of persistent efforts at reduction under anesthesia, it is found impossible to put the bones in place. Failure may be due to the small size of the tear in the capsule, but, as a rule, it is due to the interposition of soft parts. If the edge of the articular surface was broken by the injury, it is evident that reduction may be impossible. In all such cases bloody reduction of the dislocation ought to be resorted to as early as possible. The joint must be opened as much as may be necessary to effect reduction.

[In experienced hands, when reduction of a dislocation fails after the proper trial of the usual methods one should never hesitate to operate at once. Prolonged and forcible attempts at reduction are dangerous. With proper technic the operation is a very simple matter, and seldom fails · to reduce a recent dislocation. In the majority of instances one will find a sufficient cause which prevented the usual easy reduction of the dislocation; for example, a small fragment of bone, or an interposed tendon or muscle. -ED.]

If a dislocation is not reduced, there results the condition known as an "old dislocation," complicated frequently by the formation of a new joint (a nearthrosis). Therapeutic measures in such cases will be determined by the conditions found on careful examination. If the function of the new joint is satisfactory, as happens in very rare

cases, no interference is indicated, and the surgeon should confine his efforts to enhancing the mobility of the new joint by means of passive exercises, etc.; but if the opposite is the case, there is nothing left but resection or arthrotomy, followed by the replacement of the dislocated articular head in the original cavity. The latter should be the usual procedure, if for no other reason, because these cases of unreduced luxations are presenting themselves for treatment earlier than they used to, and because the results obtained by replacement are, as a rule, much better than anything that can be hoped from resection. It is always more desirable, however, that reduction be effected as early as possible.

[There is really no necessity for an old dislocation. In the recent state reduction is always possible. Nevertheless many cases come to the surgeon. The same rules should be followed in the reduction as those advised for recent dislocations: first, an attempt at reduction without operation, always under anesthesia; if this fails, an immediate operation, so that the patient is subjected to only one narcosis. In some cases of old dislocations resection gives much better results than reduction; this is especially true at the shoulder and elbow. The functional result of a proper excision of these joints is always excellent. On the other hand, in cases in which perfect reduction is possible, the joint changes from the old injury are so advanced that marked restriction of motion is always present, and the function of the arm is never as good as after a resection. Experience and the study of the soft parts around the joint will usually indicate the better procedure.-ED.]

II. FRACTURES OF THE SKULL

In the study of fractures of the skull it is of interest to know that the doctrine of a certain elasticity of the skull promulgated by Bruns has been confirmed by recent inves