Livor mortis (sometimes misspelled “liver mortis”) is the discoloration that appears on a body after death as blood settles downward by gravity. It begins the moment the heart stops beating and is one of the earliest visible signs that death has occurred. Forensic investigators rely on it to estimate how long someone has been dead and whether a body has been moved.
How Livor Mortis Happens
While you’re alive, your heart keeps blood circulating evenly throughout your body. The moment circulation stops, gravity takes over. Blood begins pooling in whatever part of the body is closest to the ground. If someone dies lying on their back, blood settles into the back, buttocks, and backs of the legs. If they die face down, it pools in the chest, face, and front of the limbs.
This pooling produces a visible reddish-purple discoloration on the skin’s surface, because blood is collecting and expanding inside the tiny capillaries of the skin. The process is entirely passive: no chemical reaction drives it, just the steady pull of gravity on fluid that is no longer being pumped.
The Timeline of Lividity
Livor mortis starts immediately after death, but it takes time to become visible. Faint discoloration typically appears within 30 minutes to 2 hours. Over the next several hours, the color deepens and spreads as more blood accumulates in the dependent areas.
During roughly the first 12 to 18 hours, lividity is still “unfixed,” meaning it can shift. If you press on a discolored area during this window, the skin temporarily turns pale as blood is pushed out of the engorged capillaries. If the body is repositioned, the lividity gradually migrates to the new lowest point. This happens because the red blood cells are still intact and can move freely within the blood vessels.
After that window closes, lividity becomes permanent, or “fixed.” Fixation occurs through two processes. First, red blood cells begin to break apart inside the blood vessels. Second, the hemoglobin (the pigment that makes blood red) leaks through the vessel walls and stains the surrounding tissue. Once that staining happens, no amount of pressure or repositioning will make the discoloration disappear. It works much the same way a bloodstain on fabric becomes permanent once it soaks in.
What the Color Reveals
Standard livor mortis appears dark red to purplish. But certain conditions change the color, and those variations carry important forensic clues.
- Cherry red: Carbon monoxide poisoning is the classic cause, because the gas binds to hemoglobin and produces a distinctly bright red compound. Cold temperatures also create cherry-red lividity. When skin temperature drops to around 10°C (50°F), oxygen dissolves more readily into pooled blood and binds more tightly to hemoglobin, shifting the color from dark red to cherry red. Bodies stored in refrigeration commonly show this effect.
- Pink: Cyanide poisoning can produce a pinkish hue, because cyanide prevents cells from using oxygen, leaving it bound to hemoglobin in unusually high concentrations.
- Dark purple or near-black: This deeper discoloration is typical when death involves conditions that severely deplete blood oxygen, such as asphyxiation or certain cardiac events.
Interestingly, the color can change after death depending on environmental shifts. A body moved from cold storage to room temperature may transition from cherry red back to a purplish tone as the blood warms, oxygen solubility drops, and hemoglobin releases its bound oxygen.
Contact Pallor and Pressure Points
Not every part of the body’s underside shows discoloration. Areas where the body presses firmly against a surface, like the shoulder blades against a floor or the back of the calves against a bed, remain pale. This is called contact pallor. The weight of the body compresses the capillaries in those spots, preventing blood from pooling there. The result is a pattern of pale patches surrounded by lividity that essentially maps the surface the person was resting on.
Tight clothing, belts, and watchbands create the same effect. A band of pale skin where a waistband pressed into the body, bordered by purple discoloration on either side, is a common finding. These patterns give investigators detailed information about the body’s position and what it was in contact with after death.
How Forensic Investigators Use It
Livor mortis is one of three classic early changes (alongside rigor mortis and body cooling) used to estimate time of death. Because lividity follows a rough but predictable timeline, its stage helps narrow the window. Unfixed lividity that blanches with pressure suggests the person died relatively recently, within the last 12 to 18 hours. Fully fixed lividity points to a longer interval.
Perhaps more importantly, lividity reveals whether a body has been moved. If someone is found lying on their back but lividity is fixed on the front of the body, they clearly died face down and were later repositioned. Dual lividity patterns, where partial discoloration appears on two different sides, can indicate a body was moved during the unfixed phase but before fixation was complete.
Investigators also use lividity to distinguish postmortem skin changes from injuries. A bruise involves blood that has leaked out of damaged vessels into tissue, while early lividity is blood still sitting inside intact vessels. Pressing on unfixed lividity pushes the blood away and the skin blanches. Pressing on a bruise does not, because the blood is already trapped outside the vessels. Once lividity fixes and hemoglobin stains the tissue, this distinction becomes harder to make, sometimes requiring a pathologist to examine tissue samples under a microscope.
Tardieu Spots
In areas of heavy blood pooling, small dark spots sometimes appear that look like tiny bruises. These are called Tardieu spots. They form when the sheer weight of settling blood puts enough pressure on small vessel walls to rupture them, allowing blood to leak into surrounding tissue in pinpoint clusters. They’re most commonly found on the surface of organs or on skin in heavily dependent areas, and they’re a normal part of the postmortem process rather than a sign of injury.