The greatest modifications in the appearance and nature of the apertures of entry are dependent on previous deformation of the bullet, when all special characteristics are lost, and it becomes impossible to form any opinion as to the type of bullet concerned. These modifications are naturally far more common in the aperture of exit, since the bullet so often acquires deformity in the body as the result of impact with the bones. Further remarks on this subject will be found with the description and comparison of the various bullets on p. 81.
Fig. 24.—Superficial Thoracico-abdominal Track.
Small entry: discoloration of surface over costal margin from deep injury to skin; well-marked 'flame' gutter exit (see fig. 18)
2. Direct course taken by the wound track.—This character primarily depends on the velocity with which bullets of small calibre are made to travel, and on the small area of the tissues upon which they operate. In this relation the degree of velocity retained by the bullet is often of minor importance, provided it be sufficient to penetrate the body. Fired within a distance of 2,500 yards there is little doubt that a bullet of the Lee-Metford, Mauser, or Krag-Jörgensen types, passes straight between the apertures of entry and exit when these are of the type outline, even when the bones are implicated. By reason of the small size of the projectiles, their shape, and the spin and velocity transmitted to them, there is no reason why at a sufficiently short range they should not traverse the body from the crown of the head to the sole of the foot. The necessary conditions of position and distance for such an injury are obviously not often obtained, but it may be pointed out that the Belgian Mauser rifle at a distance of five yards is capable of driving a bullet 55 inches or nearly five feet into a log of pine-wood. Many examples of long tracks will be referred to later, but the following instances may be of interest in this relation. A bullet entering at the occipital protuberance traversed the muscles of the neck, passed through the thoracic cavity, fractured the bodies of the third and fourth and grooved the seventh and eighth dorsal vertebræ, grooved the seventh and eighth and fractured the ninth and tenth ribs, traversed the muscles of the back and finally lodged against the ilium; the whole length of this track measured some 25 inches. Again, at the battle of Belmont a Mauser bullet entered the pelvis of a horse just below the anus, and traversed the entire trunk before emerging from the front of the chest: it may be of interest to mention that this animal was alive and moving about the next day, but I am sorry I can give no further information regarding his fate.
Fig. 25.—Superficial Track on external surface of Thigh.
Local discoloration of skin five weeks after reception of injury
The possibility of contour tracks travelling around the walls of the chest or abdomen has therefore rarely to be considered, except in occasional instances where the bullet fired from a long range has impinged against a bone and is retained in the body. The small volume of the bullets, however, allows the production of very prolonged direct subcutaneous tracks in the body wall, in positions where they would be manifestly impossible with projectiles of larger calibre.
Figs. 24 and 25 illustrate wounds of this nature. In the case figured in fig. 24 the bullet entered over the third rib in a vertical line above the right nipple; it then coursed obliquely down, crossing the seventh costal cartilage, and finally emerged 3 inches above the umbilicus. Where the track crossed the prominence of the thoracic margin the skin was so thinned as to undergo subsequent discoloration, while a distinct groove was evident there on palpation. In some similar cases I have seen the central part of the track secondarily laid open as a result of the thinning of the skin and consequent sloughing due to the interference with its vitality.
Short of sloughing, the skin may show signs of alteration of vitality for a long period after the injury; thus fig. 25 depicts the condition seen in a superficial wound of the thigh five weeks after the injury. The line of passage of the bullet between the two openings was still clearly visible as a dark red coloured streak. Grooves in such cases are generally readily palpable in the early stages, while later the want of resistance is replaced by the readily felt firm cord representing the cicatrix. These points are of much importance in discriminating between perforating and non-perforating wounds of the abdomen, and are again referred to in that connection.