Livor mortis
Livor mortis, also known as postmortem hypostasis or lividity, refers to the skin discoloration that occurs in a deceased individual due to the gravitational pooling of blood after the heart stops pumping. This process begins within thirty minutes to an hour post-death, as blood settles in the lowest areas of the body, creating a characteristic pattern of discoloration. The presence and distribution of livor mortis can provide investigators with important clues about the time and circumstances of death, helping to indicate whether a body has been moved after death.
While livor mortis is one of the three traditional methods used to estimate time of death, it is considered less reliable due to various influencing factors such as the individual's health prior to death and the environment in which the body is found. The discoloration typically progresses through distinct stages, reaching maximum visibility within eight to twelve hours after death, after which it becomes fixed. The color of the lividity can also vary depending on the cause of death, with specific hues associated with conditions like carbon monoxide poisoning or hypothermia. Understanding livor mortis is valuable for forensic investigations, offering insights into the events surrounding a person's death.
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Livor mortis
DEFINITION: Discoloration that occurs in the skin of a corpse shortly after death as a result of the gravitational settling of pooled blood.
SIGNIFICANCE: Although livor mortis analysis is one of three traditional methods of determining time of death, it may be the least reliable of the three because the supposedly regular rate of livor mortis development is dependent on many variables. More significant to medical investigators are coloration, which may furnish some indication of the cause of death, and its distribution, which is useful in determining whether a body has been moved.
At death the heart ceases to pump, and so circulation stops. Blood within the vessels remains liquid and, within thirty minutes to one hour, loses it ability to clot. As this blood pools, the heavier red blood cells tend to be drawn downward, into the lowest regions of the body. In this situation, any body points resting on firm surfaces will be subject to contact pressure. Because the vessels at these points are compressed, blood will not pool here. A person who dies in a supine position (lying on the back) will thus present a characteristic distribution of blood. While the back of the neck, small of the back, and thighs will generally show discoloration, contact points, usually the shoulder blades, the buttocks, the calves, and the heels, will be blanched or pale.
In the bodies of persons who were anemic or who suffered severe blood loss before death, this process, known as livor mortis (Latin for “the bluish color of death”) or lividity, might be delayed or may not develop significantly. In cases of lingering cardiac failure, lividity might even begin before death. Livor mortis is sometimes initially mistaken for bruising.
A commonly cited postmortem chronology for the development of livor mortis is as follows: perceptible lividity within thirty minutes to four hours, when patches begin to appear; development of more patches, creating broader areas of discoloration, within the next three to four hours; and maximum discoloration at eight to twelve hours after death. At the third stage, the lividity is fixed; if a blotch is subjected to thumb pressure, it will not blanch or turn pale.
A who finds a corpse lying facedown with lividity on the back side may thus justly conclude that the body was moved sometime after death. The presence of circular blanching around the waist would indicate the victim was wearing clothes or at least a constricting belt at the time of death. In assessing time of death, no competent investigator would regard these chronological parameters as absolute and use them in isolation. In fact, some researchers have pronounced the twelve-hour lividity rule to be no more than a vague generalization.
The coloration associated with lividity, often reddish to reddish purple, varies depending on the cause of death. In cases of carbon monoxide poisoning, for example, the color is often described as cherry red. Nitrate poisoning produces a deep brownish, almost chocolate, color, and death from hypothermia, low body temperature from exposure to cold, makes the skin pinkish.
Bibliography
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