THE SEVERAL KINDS OF WOUNDS
(1) Incised; (2) Punctured; (3) Lacerated and Contused; and (4) Gunshot.
1. Incised Wounds
Made by sharp instruments.
General Characters.—Incised wounds are somewhat spindle-shaped, their superficial extent being greater than their depth; the edges are smooth and slightly everted, and the wounds are always larger than the weapon which inflicted them—due to retraction of the divided tissues. If a wound be in a line with the fibres of a muscle, there will be less “gaping” than when the wound is directly or obliquely across the muscle. From muscular contraction, or the elasticity of the skin, an incised wound may assume a crescentic form. The cellular tissue is infiltrated with blood, and coagula are found at the bottom and between the edges of the cut. It must be borne in mind that a wound with smooth edges may be made by a blunt weapon over bones near the surface, as on the scalp and over the tibia or shin, but a certain amount of contusion may, in most cases, be detected by careful inspection a short time after the receipt of the injury.
It is often of importance to distinguish where the weapon entered, and where it was drawn out. The end where the weapon entered is usually more abrupt than the other, which is naturally more drawn out. But in some cases I have seen, when the weapon was simply drawn across the part, both ends of the wound alike.
2. Punctured Wounds
The orifice is generally a little smaller than the weapon.
A stab may sometimes present the appearance of an incised wound; the depth will, however, help to distinguish the one from the other. The wound may not at all correspond with the shape of the weapon, and the same pointed instrument may produce very different-shaped wounds in different parts of the body. Much depends upon the movement of the instrument in the action of puncturing; in the case of a double-edged instrument the wound will most probably be fusiform or diamond-shaped. When made with a knife the wound may be wedge-shaped if the knife have a thick back. A circular weapon splits the skin and leaves a slit; broken glass and pottery act in a similar way, but the wounds may have jagged edges and show signs of contusion in them. On dissection, two or more punctures may be found in the soft parts, with only one external orifice; these are due to the weapon being only partially withdrawn at each stab. Punctured wounds are always more dangerous than incised. They cause little, if any, hæmorrhage externally, unless a large vessel, such as the femoral artery, be injured, but they may cause internal hæmorrhage or penetrate a viscus, e.g. the lung or heart. These wounds generally heal by suppuration, and not infrequently an abscess is formed in and around the track of the wound. Perforating wounds generally have a large entrance wound with inverted edges, and a small exit with everted edges; if the weapon be rough, the reverse may be the case.
3. Lacerated and Contused Wounds
The edges of these wounds are never smooth, and generally do not correspond at all with the weapon. A considerable amount of contusion or bruising surrounds the solution of continuity of the part. Hæmorrhage from these wounds is usually slight. A point of considerable interest may arise in connection with this class of wounds; the defence may declare that the injury was the result of a fall, and not due to a blow. The history of the case, and the presence of a bruise where no theory of a fall can explain its existence, will often afford the only solution of the difficulty. Lacerated wounds heal by suppuration, generally with more or less sloughing, and leave a permanent scar. Scratches with the finger-nails may be considered as lacerated wounds, but the skin is merely abraded, not divided. They are never important as wounds, but often as a proof of a struggle in cases of rape, &e. Bites are also lacerated wounds. The diagnosis of lacerated and punctured wounds, whether inflicted before or after death, will depend on much the same grounds as those of incised wounds, hæmorrhage, vital reaction, &c.
Table of Differentiation Between
Ante-mortem and Post-mortem Wounds:
4. Gunshot Wounds
The appearance which gunshot wounds present will to a great extent depend upon the form of the projectile, and the distance at which the firearm was discharged. Round halls make a larger opening than conical. Small-shot, fired within a short distance of the body, make one large ragged opening. The scattering of the shot depends on the calibre of the gun, on the charge of powder, and essentially on the distance. A charge of ordinary (No. 5) shot, to make a single hole, must have been fired at less than one foot; but experiments should always be made with the alleged weapon. A patent cartridge would make a single hole at a considerable distance—five or six yards. Round bullets may split, but the conical ones seldom do. The edges of wounds produced by the discharge of firearms are always more or less ecchymosed; this condition appears in about an hour after the infliction of the injury. If the ball strikes obliquely, the edges of the wound may be much lacerated, or the opening may be valvular and of small size, if the skin over the part be in any way tightened, or if a conical ball has been used. The injury to bones is greater from conical than from round balls. The old round balls were easily deflected; the conical are not so easily turned aside. The track of the ball widens as it deepens. This is the reverse of an ordinary punctured wound. The ball may either lodge in a part, or perforate it. Should it have lodged, it must be preserved and compared with the alleged firearm. Bits of clothing or wadding may be carried into the wound. The latter should be carefully kept, as they may prove important as a means of identification.
The aperture of entrance and exit must, if possible, be determined. On this point there is much difference of opinion. The wound of exit is always smaller than the wound of entrance (Casper). In this opinion Casper agrees with M. Malle, Olliver d‘Angers, and M. Huguier, but is opposed by Taylor, M. Matthysens, and others. “The characters of a gunshot wound,” says Assistant-Surgeon Neill, “are those of a contusion and laceration of all the tissues. Sometimes they are so simple as to bear resemblance to a punctured wound, particularly if a rifle-ball (conoidal), revolving on its long axis, has passed through the soft parts at a great speed, but within a few hours it resembles a contusion. The wound of entrance, as it has been termed, bears no comparison in size or shape to that of the exit when a rifle-ball has caused the injury. In the former you see the edges of the wound curving inwards, and the circumference small, with little or no hæmorrhage. In the latter, the wound is large, with torn and irregular edges projecting outwards, and perhaps only slight oozing of blood. In a short time, averaging an hour, round the entrance wound slight redness begins, gradually extending to about two inches round its orifice. Again, this colour changes to a blue- or greenish-black, and you see all the appearances of a severe bruise, with a small wound of the skin, its edges still curved inwards. In the exit wound the discoloration of the skin is not apparent.” The probable reason for the discrepancies in the statements of observers, as to the characters of entrance and exit wounds, may be found in the fact that experiments have been conducted with different-sized balls, different kinds of weapons, with varying quantities and qualities of the powder used, the character of the wads, and with varying velocities and distances. As pointed out by M. Roux, the two openings may be equal if the ball preserves the same velocity through the tissues as it possessed before entrance; the entrance hole is smaller than the exit, when the ball has lost much of its trajectile force, and enters the softer parts of the body first; the entrance is larger than the exit, when the ball first enters through the denser tissues of the body, and leaves through the softer.
The opening of entrance made by the ball has generally, but by no means always, inverted edges. The edges of the exit opening are everted, bloody, and raw; but both the entrance and exit wounds may be everted in fat persons, due to the protrusion of the fat; and this eversion may also result from the expansive power of the gases generated during putrefaction, should this condition be present. Wounds made by double shots, as from double-barrelled guns, or pistols, or from slugs fired from one barrel, diverge after their entrance into the body.
Observations during the war in South Africa threw fresh light upon the results of gunshot wounds produced by modern projectiles. Of wounds produced by the Mauser bullet, one correspondent (The Physician and Surgeon, 1900, p. 49) states that “the aperture of entrance seldom shows any bruising of surrounding tissue; frequently it has been difficult to locate it, for where the skin is dense and elastic, there is seldom any bleeding. There is never any inversion of the edges, which are sometimes circular in form, and sometimes triangular like a leech-bite. The aperture of exit, where the bullet has not been distorted, is seldom any larger than that of entrance; there is no bruising of surrounding tissue, and no eversion of the edges; bleeding varies, of course, in accordance with the proximity of large, medium, or small blood-vessels in the track, but in the vast majority of cases it is slight.”
The late Sir William MacCormac, quoted by Sir William Stokes (B. M. J., vol. i., 1900, p. 1453), says: “I saw a large number of injuries inflicted by the Mauser bullet, which is remarkable for the small wound it produces. In three-fourths, if not a larger proportion, it was impossible to tell the exit from the entrance wound, they were so similar in appearance.”
In the examination of gunshot wounds we have to consider—
1. Direction in which the Gun was fired.—The track and position of the ball in the body, coupled with the relative position of the body to a window or door through which the gun may have been discharged, and the place where the ball is found, should it have passed through the body, may assist us in forming an opinion. It is often impossible to trace the course of the ball through the cavities of the body, but through the muscles and denser structures this is more easily accomplished. The effects of the ball on surrounding objects may assist very much in finding the direction of its course. Sir Astley Cooper, by a careful consideration of the above suggestions, once correctly determined that a left-handed man had fired the fatal shot.
2. Distance at which the Charge was fired.—In the case of wounds inflicted by a small shot, the scattering of the shot must be our guide. Dupuytren has related a case in which a fowling-piece charged with powder alone and fired at a distance of two or three feet from the abdomen made a round hole in it and killed the man. If the weapon be fired a short distance, e.g. a few inches from the body, the skin will be scorched, smoke-blackened, and tatooed with powder, the flame may singe the hair or clothing. If discharged quite hard up to the body, the edges of the wound are freely lacerated, ecchymosed, and burnt. Smokeless powder will not cause blackening of the skin. The absence of scorching, or marks made round the wound by the half-burnt powder, allows of the assumption that the shot must have come from some distance—rather more than four feet. The absence of any of the above, however, is not an absolute proof that the shot has come from a distance.
There is no means of deciding, from an examination of a pistol or gun, when the weapon was last used. In all cases, medical men, unless sportsmen and familiar with firearms, should hand over the weapon to a gamekeeper or gunsmith, and not attempt to give an opinion on matters about which they know nothing. The following may be of use to students for examination purposes, but for nothing else: Among the products formed when gunpowder is exploded is the sulphide of potassium, but if exposed to the air some portion of this substance is converted into the sulphate of potash. If, then, the gun-barrel be washed out with distilled water, and the washings filtered, and, on the addition of a solution of acetate of lead, a black precipitate of sulphide of lead be formed, this is supposed to point to recent use; if, on the other hand, a white precipitate of sulphate of lead forms, to the use of the weapon at some more distant date than the period alleged.
CHAPTER VI
BLOOD-STAINS
It is important in medico-legal investigations to determine the nature of stains found on clothes, weapons, articles of furniture, &c. In the case of blood-stains note should be made of their incidence upon the body or in its vicinity. Blood-stains may vary in their character, incidence, and magnitude, as sprays, spirts, or jets, smears of various forms, or pools of blood.
Notes should be made of the relation of the direction of a spray of blood to the position of a wounded body when found. A plan with the position of the stains should be sketched upon the spot, and measurements taken carefully.
In the examination of blood-stains the purpose of the medico-jurist is not to demonstrate all the properties of blood, but to identify it. There is not much difficulty in ascertaining whether stains are due to blood or not; but when the question arises as to whether the blood be human or that of some other animal, the identification is more difficult and less certain.
Blood-stains vary in colour, according to the age of the stain, the quantity of blood in it—the thicker the stain the darker—and the nature and colour of the material upon which it is. Recent stains are reddish in colour, old stains brownish. This change of colour depends upon the free access of air and the presence or absence of chemical substances in the air, so that it is almost impossible to infer the age of a blood-stain by its colour. On dark-coloured materials the stains are rendered more visible by the aid of artificial light, such as candle-light; on light-coloured materials, on leather, wood, iron, and stone, they are more visible in good daylight. By reason of the coagulation and the albuminous composition of blood, dry stains stiffen the fabric when thin, and on thicker woollen materials the fine fibres become matted. On metals, such as iron or steel, they appear as dark shiny spots or smears, and when dried are often fissured or cracked. Rust may so alter blood as to produce a difference between the stains on the blade and handle of a knife. In quite recent blood-stains the general appearances are sufficient to give rise to a conclusion as to their nature, especially if the stains are large. The general features as seen by the naked eye are such that one may often recognise blood-stains as arterial by the comet shape they retain when falling slantwise on an object. Venous blood is not spurted in small jets like arterial, but blood from veins may become splashed upon objects and assume shapes similar to those produced from an arterial jet.