3. Eversion of the Lips of the Wound.—The edges or lips of a wound inflicted during life may be inverted, instead of everted, if a thin layer of muscular fibres is attached directly to the deep surface of the skin, as is the case in the scrotum. The eversion of the edges of the skin is due to their elasticity, and ceases to occur as soon as the skin loses its vitality. Consequently eversion ceases to occur soon after death, within a very few hours. A wound in which the edges are neither inverted or everted was therefore inflicted after death. If this sign is present and marked, the wound was inflicted during life or within two or three hours or less after death. If this sign is present but very slightly marked, the wound may have been made even somewhat longer after death.
4. Retraction of the sides of the wound is also dependent on their vitality and ceases to occur when this is lost a few hours after death. In the retraction of the edges of the wound we have all the parts involved, but unequally. The muscles, arteries, skin, and layers of connective tissue all retract, varying in the degree of retraction according to the order in which they are named. In different parts of the body this comparative order of retraction is liable to more or less variation. Every surgeon is familiar with this retraction of the tissues, which necessitates certain rules in the technique of operations, especially of amputations. Muscles retract the more the longer they are and the farther the incision is made from their attachment. Without specifying a definite time, we may say that, as a rule, this retraction lasts no longer than about two hours after death, consequently when it is absent we may infer that the wound was inflicted two hours or more after death. The amount of retraction grows less and less after death for about two hours, after which it is very slight if it occurs at all, owing to the loss of elasticity of the tissues. This sign is especially useful in the case of a mutilated body where, by examining the degree of retraction of the muscles, we may infer whether the mutilation was done before or after death. The sides of a cut made on the cadaver are comparatively smooth and even, owing to the absence of the unequal retraction of the various elements, which makes the surfaces of a gaping ante-mortem wound uneven and irregular. Relying on these circumstances in the “affaire Ramus,” cited by Vibert,[621] one was able to recognize the order in which the body had been mutilated.
Other minor signs of a wound inflicted during life may be briefly mentioned. If the edges of the wound are swollen, or show signs of inflammation or gangrene, or if pus or adhesive material is present on the edges of the wound, we may infer that the wound was inflicted some little time before death. Of course, if cicatrization has commenced, some days must have elapsed before death after the wound was received. If the blow causing a contusion was inflicted some time before death, there will be more or less of a general swelling of the region, partly due to the blood effused, but also partly due to œdema.
It is not always easy to say whether a fracture was produced while the body was living or dead. If the body was still warm when a post-mortem fracture was produced there is little difference from an ante-mortem fracture, except that there may be a little less blood effused. In a fracture produced after rigor mortis has set in there is little or no blood effused. In the case of fractures the presence of callus, indicating the process of repair, shows that the accident occurred during life, and, as we have already seen, we may form some idea of the length of time elapsed between the injury and the time of death. On the cadaver it is said to be harder to cause fractures and lesions of the skin than on the living body. Casper says that fractures of the hyoid bone and the larynx are impossible after death, and he also was not able to rupture the liver or spleen.
In distinction to the characteristic signs of a wound inflicted during life, we may mention briefly some of the signs of post-mortem wounds when the wound has been inflicted from two to ten or twelve hours or more after death:
(1) The hemorrhage is slight in amount and may fail altogether.
(2) The character of the hemorrhage is venous, corresponding to the source of the hemorrhage from the veins, the arteries being nearly empty after death.
(3) The edges of the wound are not deeply stained, and this staining may be removed by washing. The spaces between the tissues are not infiltrated with blood.
(4) The blood remains either entirely fluid or, if there are clots, these are softer than those in an ante-mortem wound, and only a portion of the blood is thus clotted. There are no clots plugging the open mouths of the arteries on the surface of the wound; the veins may or may not be closed by an imperfect clot.
(5) The skin of the edges is not everted or inverted.