The gravity-dependent, purplish-colored settling of blood into blood vessels and soft tissues after death is known as livor mortis or Postmortem Lividity. The greatest way to see Livor Mortis is via the skin. When the heart’s power is no longer sufficient to pump blood, it follows gravity and pools in the body’s dependent regions.
After death, vascular tone is also reduced, causing blood to leak out of tiny vascular channels and into the surrounding tissues. Because blood is pigmented, it ultimately leaks from blood vessels, breaks down (hemolyzes), and colours the tissues over time, resulting in “fixed” lividity.
The livor mortis settles at the rear surface of the body because most decedents are put in a supine position. The livor has “cleared” in areas that contact the autopsy table. Typically, livor mortis is evident 30 minutes to an hour after death, and it might change or be cleaned for 8–12 hours. These timeframes might differ significantly. Because livor is visible in the tissues as purplish-colored blood, anaemic people or those who have died from a major haemorrhage may have little or no livor. Livor mortis might be difficult to detect in those with darker complexion. Internal organs such as the lungs can be utilised to measure livor in such instances.
The following are the Reasons of Postmortem Lividity:
▪️ Circulation halting
▪️ Blood’s tendency to sink to the most dependent regions due to gravity; accumulation in toneless BV and capillaries
▪️ Backward venous blood flow – from the venular end to the capillaries [adds to the blueness of PM staining]
Color: Hue – Bluish purple, however various sections of the body may have varied hues. The quantity of decreased Hb in the blood determines the intensity. The presence of large quantities of decreased Hb results in a deep purple hue. Parts of the body that have had their blood drained appear pale.
The cause of death may be a factor too. If poisoning is the cause of death, Livor mortis may appear in various colours depending on the toxin.
Carbon monoxide poisoning causes the livor mortis (as well as the blood) to turn bright red, which is a crucial colour to detect in order to do carbon monoxide testing. Red to salmon-pink lividity is caused by cold, bodily freezing, refrigeration, and cyanide poisoning.
More PM staining and its causes are included in the table below:
Black – Mummified bodies, Opiates
Bluish Green – Hydrogen Sulphide (H2S)
Bluish Violet – Asphyxia
Bright Pink – Hypothermia
Bright Red – Refrigerated Body, Hydrogen Cyanide (HCN), Burns
Grayish Brown – Clostridium Perfringens
Cherry Red – Carbon Monoxide
Chocolate – Acetanilide, Aniline, Bromates, Chlorates, Nitrites, Bromites, Nitrobenzene, Potassium Bicarbonate
Dark Brown/Yellow – Phosphorus
Manual pressure can be used to clear livor mortis that isn’t “fixed,” but it can’t be used to clear fixed livor mortis.
In the livor mortis, any item lying against the lower section of the body might create a pattern. If a body is moved before the livor is fixed, the livor may shift, resulting in the formation of a second pattern. Two livor patterns on a body can help anticipate how a body will move once livor mortis has developed.
The blood stains the tissues between 10 and 24 hours after death and becomes more difficult to remove. Livor may shift after 10 hours, but this shifting is not easy to see.
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