Surgical Experiences in South Africa, 1899-1900 / Being Mainly a Clinical Study of the Nature and Effects of Injuries Produced by Bullets of Small Calibre

by George Henry Makins

The amount of fissuring at the aperture of entry was often not so extensive as I had been led to expect. Fig. 61 is a diagram illustrating a fairly typical instance; in some cases no fissuring existed. As a rule the nearer to the base, the greater was the amount of fissuring observed. The fissures were sometimes very extensive in this position, probably as a result of the lesser degree of elasticity in this region of the skull. Again, when the aperture of entry was near the parts of the vertex where sudden bends take place, considerable fissuring of the same nature as that seen in the superficial tracks (fig. 68) was produced in the flat portion of the skull above the point of entrance.

Radial fissuring around the aperture of entry in the skull scarcely corresponds in degree with that seen when the shafts of the long bones are struck, and is far less marked and regular than when one of these small bullets strikes a thick sheet of glass set in a frame. I saw several apertures in the thick glass of the windows of the waterworks building at Bloemfontein produced by Mauser bullets. They differed little from the opening seen in an ordinary plate-glass window resulting from a blow from a stone, except perhaps in the regularity and multiplicity of the radial fissures. As in the skull, the opening was a little larger than the calibre of the bullet, and the loss of substance on the inner aspect considerably exceeded that on the outer.

The degree of fissuring is probably affected by the resistance offered by the particular skull, or the special region struck, but as a rule the elasticity and capacity for alteration in shape possessed by the bony capsule, is opposed to the production of the extreme radial starring observed in the long bones or a fixed sheet of glass. Corroborative evidence of the influence of elasticity in the prevention of starring is seen in the limited nature of the comminution of the ribs in cases of perforating wounds of the thorax.

In the most severe cases we can only speak of the 'aperture' of exit in a limited sense in so far as the opening in the scalp is concerned; this was often comparatively small, not exceeding 3/4 of an inch in diameter. Beneath this limited opening in the soft parts, the bone of the skull was smashed in a most extensive manner. The portion exactly corresponding to the point of exit of the bullet was carried altogether away, but around this point a number of large irregularly shaped fragments of bone, from 3/4 to 1 inch in diameter, were found loose, and often so displaced as to expose a considerable area of the dura-mater. Beyond the area of these loose fragments, fissures extended into the base and vertex, in the latter case often being limited in their extent by the nearest suture.

Over extensive fractures of this nature general œdema and infiltration of the scalp, due to extravasation of blood, were present. When the exit was situated in the frontal region ecchymosis often extended to the eyelids and down the face, while in the occipital region similar ecchymosis was often seen at the back of the neck.

The opening in the dura mater at the aperture of entry was either slitlike, or more often irregular from laceration by the fragments of bone driven in by the bullet. At the point of exit a similar limited opening corresponded with the spot at which the bullet had passed, while separate rents of larger size were often seen at some little distance. The latter were the result of laceration of the outer surface of the membrane by the margins of the large loose fragments of bone above described.

Injury to the brain more than corresponded in extent to the fractures of the bone. Pulping of its tissue existed over a wide area both at the points of entrance and of exit. In the former position the amount of damage was the less, the gross changes roughly corresponding with the tissue directly implicated by the bullet itself, and the fragments of bone carried forward by it. The degree of splintering of the skull therefore in great part determined the severity of the lesion. At the exit aperture much more widespread destruction existed, while masses of brain tissue, small shreds of the membranes, fragments of bone, and débris from the scalp were found occasionally bound together by coagulated blood and protruding from an exit opening of some size. The largest masses of such débris were most often seen in instances in which the bullet had entered by the base to escape at the vertex of the skull.

The brain in the line of injury suffered comparatively slightly, but small parenchymatous hæmorrhages into its tissue indicated in lesser degree the same type of injury undergone by the mass of brain pulp and small blood-clots found at the external limits of the wound. Beyond this extensive hæmorrhages at the base of the skull were common.

With regard to the extensive character of the brain destruction in the region of the aperture of exit, it must be borne in mind that this lesion corresponds in position with one which would exist even if the injury were of a non-penetrating degree. A large proportion of the contusion and destruction is therefore explained by violent impact of the projected brain with the skull prior to the passage of the bullet, and not to the direct action of the bullet on the tissues.

These cases of 'general injury' afford a marked example of the lesions to which the term 'explosive' has been applied, and as such have an important bearing on the theories held as to the mode of production of explosive effect. The increased area of tissue damage at the aperture of exit favours the theory of direct transmission of a part of the force with which the bullet is endowed, to the molecules of tissue bounding the track made by the projectile. Thus the area of destruction corresponds with the cone-like figure which one would expect to be built up by the vibrations spreading from the primary point of impact. The exit region of the skull is subjected not alone to the force of the travelling bullet, but also to that exerted over a much wider area by the tissue to which secondary vibrations have been communicated. The brain itself is, in fact, dashed with such violence against the bone as to cause a great part of the injury.