Visceral injuries.—The frequent escape of the thoracic viscera from injury, putting aside the lungs which fill so great a part of the cavity, was very remarkable. I never saw a case in which I could assume injury to any of the posterior mediastinal viscera, although such may have occurred on the field of battle. An injury to the œsophagus, for instance, would almost of necessity be accompanied by wound of either one of the large vessels, even the thoracic aorta, or the spinal column. I was somewhat surprised, however, to learn on enquiry from surgeons who had seen a large number of the dead and dying on the field, that thoracic wounds, putting aside those that directly implicated the heart, were responsible for but a small proportion of the fatalities.
The escape of the posterior mediastinal viscera, the great vessels, and the heart, is, I believe, to be explained by the fact that all are supported and held in position by the loose meshed mediastinal tissue, which allows for their displacement after the manner observed in the case of the vessels and nerves lying in the loose tissue of the great vascular clefts.
Wounds of the heart.—Perforating wounds of the heart were probably fatal in all instances, in spite of the fact that, in some patients who survived, the position of wound apertures on the surface of the body made it difficult to believe that the heart had not been penetrated. (See cases below.)
In the case of this organ, we must bear in mind its constant variations in bulk, its elastic compressibility, and its variations in position in systole and diastole. The variations in bulk and position would be capable of explaining the escape of the organ from injury at some particular moment, when a second shot apparently through the same wound track might implicate it. Beyond this, reasoning from the case of analogous hollow viscera, as the arteries or the intestine, a bullet might readily score the surface of the heart without perforating its cavity.
Such accidents were observed. Thus, in a case examined by Mr. Cheatle, the patient died of suppurative pericarditis, secondary to a wound of which the external apertures had closed. In this patient both auricle and ventricle were scored externally by the passage of the bullet.
I am, however, disinclined to allow that many patients survived direct blows on the heart, since I believe that in the majority if not in all cardiac wounds the actual cause of death was not hæmorrhage, but sudden stoppage of the heart's action. This is to be inferred from the fact that severe external hæmorrhage did not occur; in some cases the shirt was hardly stained, and in all death occurred in the course of a very few minutes. Again, in none of the patients whom I saw who had received possible wounds of the heart-wall were there evident signs of hæmo-pericardium. In view of the difficulty of detecting this condition from physical signs, this argument is naturally not of great weight, but must be allowed.
One or two death scenes from cardiac wound were described to me. In one the patient muttered 'They have got me this time,' and died quietly; in a second the patient's face became ghastly pale, he lay on his back with the knees flexed, clutching the ground, gasping for breath, and died only after some minutes of evident great agony. The absence of any post-mortem details as to the condition of the heart in these injuries is much to be regretted.
(145) Entry, in the seventh left intercostal space, in the posterior axillary line; exit, immediately below the ninth costal cartilage, close to the position of the gall bladder.
This track in all probability involved the diaphragm twice, both lungs and pleuræ, and passed immediately beneath the heart. The liver was also perforated, but the spleen and stomach probably escaped as far as could be judged from the symptoms. The patient afterwards developed a pneumo-hæmo-thorax on the right side. The immediate symptoms were great distress in breathing and rapid irregular pulse. The difficulty in respiration was probably in part accounted for by the injuries to the lung and diaphragm. The pulse remained from 112 to 120 for three days, at first soft and hardly perceptible, later very irregular, and dropping one every fifth or sixth beat; and it seemed fair to attribute this to the shock to the nervous mechanism of the heart. The patient recovered from the chest injury.
In some other patients in whom the track passed close below the heart a disturbance of the pulse rate was noted, but this was in some cases a slowing, not below 48, in others quickening to 100, with irregularity both in force and beat.