Partial or complete division of the large vascular trunks is usually too promptly fatal to justify much consideration here. On the other hand, injuries to the intercostal and internal mammary vessels are not uncommon and should not be fatal if only they can be properly recognized and treated. It is stated that even an intercostal artery may pour four pounds of blood into the pleural cavity in case of gunshot or stab wound. The presumption would be that one of these vessels, if injured, is wounded at the site of the evident puncture. While this is usually true it is possible that a bullet penetrating may have divided an intercostal on the opposite side. If a ligature is to be applied it should be done on each side of the wound, whereas a tampon used to check hemorrhage may be packed in such a direction as to completely meet the indication. While many methods have been suggested for arresting bleeding, the surgeon will enlarge the puncture, seek out the source of the hemorrhage, and then resort to ligature or to tamponing, as the case may indicate. When the tampon is used it is well to push ahead of it a piece of gauze like a glove finger and fill this with the tampon, in order to ensure complete removal of the whole mass at the proper time.

This is true also of injuries to the internal mammary. Dennis mentions five cases, quoted to him by Langenbeck, of perforation of the chest with a sword-blade, as the result of duels among university students of Göttingen, of which number two died. The latter also stated that up to 1876 there never had been a successful ligation of this artery. The vessel, leaving the subclavian between the two heads of the sternomastoid muscle, lies in its course just to the inner side of the sternum, with the vein on its inner aspect. Near the clavicle it lies on the pleural sac, where if injured the pleura will not escape. Lower down the pleura is not necessarily opened, although it rarely escapes. As Dennis shows, the inference from this is that tamponing the wound in the two upper intercostal spaces is impracticable, while below these it might succeed, as the triangularis sterni lies between the pleura and the artery. The mortality of the injury has been stated to have been nearly 70 per cent. Diagnosis is not difficult so long as the blood escapes externally. With a wound properly situated and rapid accumulation of blood within the chest, and increasing collapse, assumption of the injury or provisional diagnosis will scarcely prove fallacious.

The internal mammary when injured should be secured. The operator need never hesitate to resect a portion of the sternum, or the rib ends or cartilage, in order to expose it, since no danger can be so great as that of not finding it. Incision may be made along or between the ribs, parallel to them, or over the known course of the artery. After retracting the tissues down to the bone a sufficient amount of the bone should be removed to afford space for the examination. The pleura should be first separated, care being taken not to inflict upon it more than a minimum of injury. A T-shaped incision will afford more room when the case is complicated. The ends of the vessel having been found and secured, it becomes then a question of emptying the chest of the blood already accumulated. This is preferably done by incision placed laterally and sufficiently low, with the introduction of a drainage tube. Should the blood be already coagulated the incision should be made sufficiently wide to permit of breaking up the clot and completely removing it.

Treatment.

—In general, with regard to the treatment of all these injuries, it should be said that, in addition to whatever local measures may be indicated, general rest of the parts should be secured by as complete immobilization of one or both sides as can be effected. This should be made a part of the treatment of all fractures, simple or compound, as well as of all perforating injuries. Anodynes, hypnotics, and the like need to be used both to restrain motion and to allay cough, either of direct or reflex origin, by which harm is always done.

THE THORACIC WALLS.

The complex structure of the thoracic walls is not exempt from the infections and other diseases which may involve skin, muscle, cartilage, and bone. Thus upon its surface all sorts of phlegmonous lesions may occur, assuming carbuncular or localized type, or occasionally ending in widespread gangrene, usually of that particular type which is due to the morbid activity of the gas-forming bacilli, whose first expression is a gangrenous emphysema. These infections occur not only in consequence of some external irritation, but are seen after the infectious fevers, as well as in connection with syphilis, tuberculosis, scurvy, actinomycosis, and other forms of infection. Tuberculous disease beginning on the exterior of the chest wall may spread to the interior and even deeper, and, vice versa, tuberculous lesions beginning within the chest spread to the adjoining bone, producing caries, and then to the exterior surface, the resulting sinuses being irregular and sometimes opening at a point at considerable distance from the origin of the trouble.

All the infectious processes, whether slow or rapid, need radical attack, including free incision, curetting, removal of diseased bone, cauterization of the affected area, and suitable dressing and packing. Carious ribs or portions of the sternum may be removed without fear, it being necessary in certain advanced cases to remove nearly the entire sternum. Any concealed focus of disease is sure to spread and do more harm than will a well-directed attempt to eradicate it. Infection originating within the bone may spread in either direction, and may give rise to pleurisy, with adhesions, and possibly even subsequent abscess of the lung. The same is true of the diaphragm, while products of infection travelling in the proper direction may cause the beginning of an extensive subphrenic or hepatic abscess.

Fig. 505