The kind and condition of a weapon which has produced a given incised wound may often be learned by an examination of the characteristics of the wound.
Weapons cutting by their weight as well as by the sharpness of their edges, such as axes, etc., may cause a certain amount of contusion about a wound; they crush the soft parts to a certain extent, and the bones may be indented or even fractured.
Wounds caused by fragments of bottles, pieces of china, earthenware, or glass, though strictly speaking incised wounds, are often curved, angular, and irregular, and their edges jagged and contused.
Wounds caused by scissors may sometimes be of the nature of incised wounds. When they present a double wound of triangular shape, with the apex of the triangle blunt, they are more of the nature of punctured wounds. In general a “tail” or long angle in the skin at one end of an incised wound indicates the end of the wound last inflicted, and some light may thus be thrown upon the inflicter of the wound.
Incised wounds present very favorable conditions for healing by primary union, but often fail in this and heal by secondary union. When an incised wound fails to unite by primary union, bleeding continues for several hours or even as long as a day, the blood being mixed more or less with a serous discharge. The latter continues until the third day or so. By the fourth or fifth day the surface has begun to granulate, and there may be a more or less profuse purulent discharge from the surface. The granulating surfaces do not necessarily discharge pus, however. For some days, therefore, after the infliction of an incised wound, or until the surface is covered with granulations, the characteristics of the wound permit of a diagnosis as to the nature of the wound.
The diagnosis of an incised wound is generally without difficulty. Some wounds by blunt instruments, however, in certain regions of the body, resemble incised wounds very closely. Such instances are found where a firm, thin layer of skin and subjacent tissue lies directly over a bony surface or a sharp ridge of bone. These are seen most often in the scalp or in wounds of the eyebrow where the sharp supra-orbital ridge cuts through the skin from beneath. The diagnosis of an incised wound can often be made with great probability from the cicatrix. This is especially the case if the wound has healed by primary union and the cicatrix is linear.
The prognosis in incised wounds is good as to life unless a large vessel has been divided or unless an important viscus has been penetrated. The prognosis as to function varies with the position and extent of the wound, and the circumstance of the healing of the wound.
Punctured Wounds, Stabs, etc.—These are characterized by narrowness as compared to depth, though the depth is not necessarily great. They are more varied in character than incised wounds owing to the great variety of form of the weapons by which they may be made. From the form, etc., of a particular wound we may often infer the variety of weapon by which it was produced. According to the weapon used, punctured wounds have been divided into several classes, of which M. Tourdes distinguishes four: 1st. Punctured wounds by cylindrical or conical instruments like a needle. If the instrument be very fine like a fine needle, it penetrates by separating the anatomical elements of the skin, etc., without leaving a bloody tract. Such wounds are generally inoffensive, even when penetrating, if the needle is aseptic, and they are difficult to appreciate. On the cadaver it is almost impossible to find the tract of such a wound. If the instrument be a little larger it leaves a bloody tract, but it is difficult to follow this in soft tissues, more easy in more resistant structures, such as tendon, aponeurosis, cartilage, or serous membrane.
If the instrument be of any size this variety of punctured wounds presents a form quite different from that of the weapon. Instead of a round wound it is generally a longitudinal wound with two very acute angles and two elongated borders of equal length, showing but little retraction. This is the shape of the wound even when the instrument producing it is so large that the resulting wound resembles that made by a knife (see Fig. 2). The direction of the long axis of these wounds varies in different parts of the body and is uniform in the same part. Their shape and direction are explained by the tension of the skin or still more clearly by the direction of the fibres of the skin, just as with the same round instrument in a piece of wood a longitudinal opening or split would be made parallel to the grain (see Fig. 1). In some regions, as near the vertebræ, the fibres may run in different directions, and the resulting wound is stellate or triangular in shape as if a many-sided instrument had caused it. As the direction of the fibres of the various tissue layers, such as aponeuroses, serous and mucous membranes, etc., may be different, a deep wound involving several such layers would have a different direction for each layer. In illustration of this, examine the figure of a wound through the wall of the stomach (see Fig. 3).
