In lesions of the joints we may include --
Periarticular, or non-penetrating, wounds; simple penetrating wounds; Penetrating wounds with osseous lesions.

PeriarticularWounds. - They have the same characteristics as wounds of the soft parts of all regions. The only general peculiarities that deserve to be noticed are -

(1) those that concern the opening of tendinous sheaths or of periarticular serous bursae which may convey the idea of a penetrating lesion, whilst in reality the soft parts only are affected; and

(2) the danger of haemorrhage in regions where the anastomotic circles are more especially developed. Let us finally draw attention, with regard to periarticular wounds, to certain lesions of the bony apophyses that do not penetrate the articulation. The present bullets do not make contour wounds.

Simple Penetrating Wounds. -These are penetrations of the synovial membrane without osseous lesions. They are rare, and are only seen in the shoulder and knee-joints. In the shoulder because here the loose capsule may leave, for the passage of projectiles, a certain interval between the glenoid cavity and the head of the humerus; in the knee on account of the great extent of the synovial cul-de-sac under the quadriceps extensor.

Diagnosis is difficult in the first case, easy in the second. Prognosis and treatment are about the same as for wounds with osseous lesions.

Penetrating Wounds with Lesions of the Epi- physes.-On cartilage projectiles give rise to contusions, erosions, and abrasions.

On the real epiphysis bullets cause contusions, depressions, furrows, grooves, incomplete or cul-de-sac perforations, total perforations forming setons, either superficial or deep, and abrasions.

The FURROWS and GROOVES are clean, no fissures radiating from them.

The INCOMPLETE PERFORATIONS have orifices and tracks of smaller dimensions than the diameter of the bullet. Lines of fissure are rare.

TOTAL PERFORATIONS are nearly always simple. When they are peripheral, the compact outer wall of the epiphysis is divided into subperiosteal fragments, which, when pressed upon, crepitate.

The aperture of entry is clean, and its dimensions are equal to those of the bullet, but are inferior or superior according as the velocity of the bullet was average, small, or great. This aperture is rounded or oval, sometimes blocked up by the periosteum, which is fissured, but not perforated, where it seems to be punched out; or sometimes it is masked by the thick synovial membrane to such an extent that the aperture can no longer be found on the dead body. Occasionally it is surrounded by minute splinters coming from the external compact table.

The aperture of exit is larger; it is irregular, lined by splinters, that are few in number, narrow, triangular, or rectangular, often adherent, opening like shutters. Its dimensions but little exceed those of the bullet (8 to 9 millimetres).

The track is regular, and either cylindrical or conical. Fissures, when they exist, are generally under the cartilage or the periosteum; they do not gape. They may be absent, or, on the contrary, be deep and branching. The more the tissue of the epiphysis is resistant (trochlea of the humerus,condyle), the more the division is complete, the easier is comminution of the articular fragments.

The track is free of small remains of splinters.

Such are the simple lesions. In their vicinity complex ones are found, but in truth more rarely. The head of the bone is separated in the joint without splintering, divided into fragments, which are more sedentary than propelled in various directions, as they are kept together by the capsule and the corresponding articular surface. It is a remarkable fact that in these cases capsular fragments and those of the soft parts are most often not in connection with the bony traumatism; the capsule is preserved, and may even be crossed in a linear manner. The narrowness of the capsular lesions and the slight traumatisms produced by the present bullets explain to a great extent the favourable evolution of these wounds.

Such are the lesions seen on the undoubtedly epiphysial portion of the osseous extremity.

When the bullet penetrates at the level of the growing cartilage, it gives rise to lesions both of the epiphysis and of the diaphysis.. a clear aperture of entry, an aperture of exit with splinters, and long fissures that radiate in the articulation and above it.

Again, we see these same lesions when the bullet keeps away from the growing cartilage, but then the fissures, though in the articulation, do not radiate below this cartilage.

Finally, in real joint lesions the damage is generally limited, the splinters and the fragments are few in number, adherent and kept in their place by a capsule which is but little open; solutions of continuity of the limb are unimportant and rare. Epiphysial lesions are therefore, as to their extent both in length and in breadth, very different from lesions of the diaphysis, and we may often regard them in the light of simple fractures, Sometimes we have to deal with ABRASIONS. The damage done by large pieces of shell is very different, both as regards extent and complexity, but it takes effect much more often on the soft parts than on the articulation itself. When the bones are implicated, if the joint is at the same time widely opened, we generally see the same type of lesion as with bullets.

General Consideration of the Types of Articular Fractures by Projectiles.-We have shown that these types are dominated by three conditions, the most important of which are the two first: the part hit, the architectural constitution of the bone, the velocity of the bullet or the range distance.

1. The Part Hit. - Bullets that reach the bone at the same point always produce identical or analogous lesions. Therefore, when we are well up in our pathological anatomy, we can affirm that such and such a lesion exists in a wounded man.

The important point for us to fix in an articulation is the line of the growing cartilage. Beneath this is the real epiphysial tissue, more or less spongy, with short trabeculae. Here the bullet produces a special lesion, epiphysial. Above this the tissue of the epiphysis and of the diaphysis, or of the diaphysis alone, of different constitution, presents lesions that are also different, and offer the type both of the epiphysis and of the diaphysis. Higher up towards the diaphysis the lesion is a lesion of the diaphysis.

2. Architectural Constitution.-The spongy tissue or articular bulb, subjacent to the line of the growing cartilage, shows localized but not radiating lesions. The subjacent tissue becomes perforated and fissured, and, as the archi- tectural fibres become shorter as we approach the margins of the bone, the fissures will be all the shorter in pro- portion as the lesion will be more peripheral. For each articulation the fissures take the directions forced on them by the disposition of the architectural fibres.

3. The Velocity of the Bullet fixes, not the osseous type or its radiations but the state of comminution. The greater the velocity, the more in general is the type one of comminution. This is specially remarkable in those lesions implicating the epiphysis and the diaphysis. The diameter of the bullet also plays a certain part. The larger it is, the velocity being equal, the more the comminution.

DIAGNOSIS.-When the osseous lesions are very comminuted and accompanied by the signs of grave fractures (change of shape of the limb, abnormal mobility, crepitation), the diagnosis is evident; but nearly always, with limited lesions and slight reaction, it is less easy to establish. Yet even in these cases it is quite possible to be certain.

The pain is not at all characteristic, functional impotence is an uncertain sign. Wounded men who have perforations of the large articulations still manage to move the joints. Discharge of synovia is frequently absent on account of the narrowness of the capsule wounds.

The following furnish valuable indications: Enlargement of the aperture of exit in short distance lesions affecting the epiphysis and the diaphysis; bone-dust found in the track or in the secretions from the wound; the very five furrows or scratches seen on the bullet when it has been arrested in the limb. The clearest signs are derived from the relation of the external wounds to the region occupied by the articulation, rapid haemorrhage, arthritis, the indications given by radiography.

As modern bullets do not as a rule deviate in going through bony extremities, the position of the apertures and their relations to the joint furnish one of the most reliable signs. We may call it pathognomonic when the articulation is superficial.

Not only do these relations of the track to the joint determine the general diagnosis, but they allow us also to establish the differential diagnosis between a lesion of the epiphysis, one of the epiphysis and diaphysis, and one of the diaphysis alone.

Radiography does not give us in bony lesions of joints the striking and nearly always constant pictures that it furnishes in lesions of the diaphysis. However, radiographic indications are of great value. Lesions of the epiphysis and diaphysis are often found out by this means, and very often an educated eye will recognize a clean perforation of the epiphysis or a furrow - that is to say, the simplest lesions. More complex damage, such as the presence of fragments, is easily reproduced by radiography.

If, of all the signs, the most simple, the most practical, the most valuable, is the one furnished by the relations of the wounds to the articulation, yet we must remember that, to reap the full advantage from it, we must take into account the position the wounded man occupied at the moment of the traumatism.

Progress, Prognosis - Formerly wounds of the articulations were particularly serious. Infection was habitual. After a few days of relative quiet the joint became swollen, painful, and tense; temperature rose, suppuration supervened, the joint soon was full of pus, which became metastatic, either through mechanical means or through the spread of infection. If the case did not come under the care of a prudent surgeon, who would decide to pursue the pus by means of large incisions, to secure free drainage, and to prevent its return by the use of topics, the wounded man succumbed to purulent infection.
Things have very much changed; but it must not be imagined that simple evolution, often aseptic, of the joints that have been penetrated, with slight reaction and trifling serous or
sero-purulent excretion, is to be considered the rule without any exceptions. Prognosis of a bullet wound of an articulation should always be cautious, therefore its treatment ought always to be in the hands of a capable surgeon.
Articulations are not exclusively traversed by pointed bullets, that rarely carry infecting foreign bodies with them; joints are also penetrated by deflected bullets, shrapnel bullets, shell fragments. In such cases we must expect the appearance of arthritis, with which we must contend by employing appropriate and very active treatment.

Treatment.-Conservative treatment is indispensable in the very large majority-we may even say in the sum total -- of articular lesions produced by bullets.
In narrow, non-infected wounds, the result of bullets fired point-blank, we must be satisfied with simple dressing of the apertures and immobilization. Even if there is no bony solution of continuity, immobilization must be carried out. We must abstain from any exploration. In general there are no splinters to remove.
In larger traumatisms, produced by deflected bullets, shrapnel bullets, etc., wounds that are often contaminated, the articulation should be washed out (solution of carbolic acid, 20 per cent.; hydrogen peroxide in small quantities), after removal of all constriction by incisions; the wound is then drained. The wounded man should be kept under supervision. All transport is to be avoided, especially if the wound is seated in the lower limb and in a big joint. Shrapnel bullets and shell fragments remaining in the articulation should be removed as early as possible, but invariably with aseptic precautions.

Arthritis that has undergone suppuration necessitates prompt arthrotomy. Resection incisions should be made use of. It is preferable to make double openings rather than to limit ourselves to one incision. In these cases ablation of the free splinters is imperatively called for. If, in spite of the arthrotomy, of incisions, and of intermittent interarticular washing out, suppuration persists in abundance and in a threatening manner, we must have recourse to an atypical resection, followed by prolonged immobilization of the articulation to avoid subsequent deformity.

Amputation will be an extreme and exceptional measure, only to be utilized in threatening septicaemia symptoms.

Immediate immobilization of the articulation is procured by methods that may be at hand to treat fracture of the diaphysis.

The surgeon will endeavour to obtain immobilization during regular treatment by apparatus which leave the articulation free; these render easy the supervision of the wound and the application of the dressings, and allow him to make incisions which burrowing of the pus might necessitate.

To attain this immobilization we cannot speak too highly of our hollowed out gutter splints with valves that fulfil all these conditions.

As a general rule, moderate compression brought about by cotton-wool applied to the joint is very useful to prevent puffiness of, or effusion into, the articulation.

Passive movement must be begun very early. Naturally the nature of the lesions will here be taken into considera tion. Generally this most necessary part of the treatment is not commenced soon enough, hence stiffness of the joint and most regrettable functional loss of power.

Lesions of the Flat Bones and of the Short Bones.

Flat Bones.-Flat bones-cranial, innominate, scapula -when hit by projectiles, present contusions, linear, radiated, concentric fissures, occurring either on the side first hit, or on the opposite side, or even on both sides, with or without displacement of splinters from the internal face of the bone; indentations, furrows, and grooves which are limited to the track of the projectile, or complicated by the presence of more or less depressed splinters from the internal table; finally, both incomplete and complete perforations.

The aperture of entry of these perforations is nearly always clean and regular, having dimensions below or above the diametrical dimensions of the projectile. The track is regular. The aperture of exit is a little larger, surrounded by quadrilateral, triangular, or lunated splinters more or less adherent, varying in size from a few millimetres to 1 or 2 centimetres. Their number varies from two or three to ten, even to fifteen. Generally they are in small numbers.

Direct fissures often unite by the shortest track the two orifices of a through-and-through perforation ; there are frequently concentric fissures in addition. The more compact the bone, the more this spreading is seen. It is more observed in the cranial bones than in the os innominatum. The lesions are generally circumscribed, and complete fracture of a flat bone is impossible when it has been hit perpendicularly to its surface. Under such conditions the os innominatum cannot be fractured with solution of a bullet.

Let us draw attention to the furrows on the edges and to the abrasions of the apophyses.

Bullets that reach the flat bones at a tangent give rise to losses of substance which extend to the whole track, and which are prolonged both upwards and downwards by numerous but adherent splinters (scapula). In these cases solutions of continuity may be seen.

The fragments of large projectiles produce fissures, furrows, and extensive perforations, even sometimes abrasions.

Short Bones.-The short bones (wrist, tarsus, etc.), present contusions, furrows, perforations, crushing.

The orifices of the usual perforations are narrow, sometimes without fissures. The fissures are generally short. Comminution and also solutions of continuity are rare.

Splinters are small, adherent, and few in number; free splinters are represented by a kind of bony dust. To sum up, the damage is limited and very trifling.