What Is Livor Mortis?

Livor mortis (also called lividity, suggillation, or postmortem hypostasis) is the gravity-driven pooling of blood in the lower-lying parts of a body after the heart stops beating. It produces a reddish-purple discoloration of the skin that is typically visible about 2 hours after death and becomes fixed (no longer blanching when pressed) at roughly 8 to 12 hours. Forensic pathologists use livor mortis, alongside algor mortis, rigor mortis, and pallor mortis, to estimate the time and circumstances of death.

Death has always fascinated and terrified mankind. We’ve written and documented countless texts and treatises on disease and death, all so we can understand what’s actually happening. What most people consider macabre and morbid has also enthralled philosophers, spiritual leaders, scientists and doctors.

There are a number of changes that happen to a body after death. These changes are the result of physical and chemical shifts happening to the body as it begins to decay. There are four discernible postmortem changes that occur in the first 24 to 72 hours after death: pallor mortis, algor mortis, rigor mortis, and livor mortis. This article focuses on livor mortis and how forensic experts use it to better estimate time of death.

What Is Livor Mortis?

Livor mortis is one of the four classic postmortem signs of death. It is the appearance of a reddish or purple discoloration of the skin caused by blood settling in the lowest-lying tissues. The discoloration is typically visible about 2 hours after death and gradually becomes fixed (meaning it no longer fades when the corpse’s position is changed) over the next 8 to 12 hours.

The earliest known description of livor mortis comes from 13^th century China by Song Ci (also Romanized as Sung Tz’u, 1186–1249), a Southern Song dynasty judge who wrote Xi Yuan Ji Lu (“Collected Cases of Injustice Rectified”, 1247), widely regarded as the world’s first systematic forensic-medicine handbook. In it, he notes:

“Generally, dead persons have a slight red coloration on the back of the neck, on the top of the back, on the ribs, the back of the waist, the insides of the legs, the knees, the feet and the stomach. Check to determine if after death these corpses were laid out supine overnight. The collapse of the blood vessels may cause this slight red coloration, which does not indicate any other cause of death.”

Lividity will develop in the direction of gravity. Thus, if the corpse is lying horizontally on its back, then lividity will develop on the backside, where the pull of gravity is the strongest. If the corpse was in a sitting position, the blood will pool towards the thighs, lower back and buttocks.

What Does "Livor Mortis" Mean?

The name is Latin, like much of the vocabulary forensic pathologists use. Livor comes from the Latin verb līveō, "to be bluish", and refers to a bruise or a bluish discoloration. Mortis is the genitive form of mors, meaning "of death". Put the two together and livor mortis translates roughly to "the bluish color of death", a tidy description of the reddish-purple staining that spreads across a body once the heart stops.

You will also see the same phenomenon under several other names. Pathologists call it postmortem lividity (or simply lividity), while older texts use hypostasis (literally "standing under", a nod to blood settling to the lowest point) or suggillation. They all describe the same event: blood sinking under gravity and discoloring the skin.

One quick clarification, since it trips many people up. "Liver mortis" is a common misspelling, and the process has nothing to do with the liver. The word is livor, the Latin term for that bluish tinge.

Why Does Livor Mortis Happen?

The heart is constantly pumping blood throughout the body. At rest, it moves about 5 litres of blood every minute, roughly 7,000 to 8,000 litres (around 1,800–2,000 gallons) over a single day, and beats around 100,000 to 115,000 times in those same 24 hours. The body’s entire blood volume (about 5 litres) circulates through the system roughly once every minute. Without the heart, every organ (and every cell in those organs) would fail to receive the oxygen and nutrients that blood transports, and all of this blood would simply fall under the influence of gravity.

This is what happens after death, once the heart stops beating. The blood in the blood vessels will begin to stagnate. The cells in the blood, such as the red blood cells (RBCs), white blood cells (WBCs) and platelets will begin to “sink” in the direction of the gravitational pull. This stagnation and settling of blood corpuscles leads to the development of livor mortis, but livor mortis would not develop without another physiological change.

Autolysis

After death, cells in the body begin to decay in a process called autolysis. Certain proteins, activated by the lack of oxygen and nutrients, begin to break down cellular components, including other proteins and DNA.

This process eventually leads to the breakdown of the cells that constitute the blood vessels. The blood contained within these vessels leaks out and pools between the layers of the skin, which leads to the development and fixing of livor mortis.

Deoxygenation Of Blood

There is a color change that happens after lividity has developed. Lividity in its initial stages is a red color, like that of normal blood, but over time, the color changes to a more purple hue because the RBCs become deoxygenated.

RBCs are the cells that collect oxygen from the lungs and transport it to the peripheral tissues for consumption. It is hemoglobin within the RBCs that actually holds the oxygen. The red color of blood (the bright red seen in arteries) is a result of oxygen binding to hemoglobin. When hemoglobin releases oxygen, this deoxyhemoglobin loses that bright red color and becomes a bluish-purple.

After death, tissues consume the existing oxygen held by hemoglobin. Once that pool of oxygen is depleted, the color of the blood will change from red to purple.

What Is The Livor Mortis Timeline?

Because lividity develops on a fairly predictable schedule, it is one of the clocks investigators read to estimate the post-mortem interval (PMI), the time elapsed since death. The progression runs roughly like this:

• First 30 minutes to 2 hours: Blood begins settling almost immediately, but the discoloration is usually not visible to the naked eye until about 2 hours after death.
• 2 to 6 hours: Faint patches appear in the lowest-lying tissues, then deepen and spread across the dependent regions.
• 6 to 8 hours: The staining becomes confluent and fully developed, taking on its characteristic reddish-purple hue.
• 8 to 12 hours: Lividity becomes fixed, meaning it no longer shifts or fades when the body is repositioned.

The key test is blanching. In the early hours, pressing a thumb firmly on a discolored patch for about a minute pushes the pooled blood aside and leaves a pale mark once the pressure is released; the lividity is "unfixed". After the blood has leaked out of the decaying vessels and stained the surrounding tissue, pressing no longer clears it, and the lividity is "fixed". Where a body falls on this timeline gives pathologists a useful, if approximate, window for the time of death. These figures are guidelines rather than a stopwatch, since temperature, blood volume, and the cause of death can all stretch or compress the schedule.

How Do Forensic Experts Use Livor Mortis To Calculate Time Of Death?

There are some visible changes that take place in a body after death. These changes are called postmortem signs of death and forensic experts use them to determine the time of death or post-mortem interval (PMI), if you want to use scientific jargon.

The appearance of lividity and the associated color change that occurs over time can tell forensic experts and pathologists a good deal about when the individual died. As mentioned earlier, lividity is usually visible by about 2 hours after death and becomes fully fixed somewhere between 8 and 12 hours, though these time stamps depend heavily on external conditions. Cooler temperatures slow the departure of oxygen from hemoglobin, which delays the color change.

Lividity also may not develop in those that are anemic. Depending on how advanced livor mortis is when investigators discover the body, forensic experts can usually estimate time of death.

Livor Mortis Can Give Clues In An Investigation

Livor mortis can also give clues about how an individual might have died, or what the body’s condition was soon after death. The development of lividity can be hindered in certain parts of the skin if there was an obstruction that blocked blood supply to that area.

This perturbed area of the skin will not have red or purple coloration and will instead have normal pale skin color. This is called contact blanching.

This can tell experts whether an individual was tied up using a rope or some other material, and provide information on what sort of surface the individual was laid on. If the body was laid on a hard surface, the area of skin that made contact with the surface would not have lividity as the hard surface would obstruct the blood vessels in that area.

It can also tell investigators if the body was moved after death, depending on how lividity developed.

There are different molecules that change the color of livor mortis. In carbon monoxide poisoning, lividity is a persistent cherry-red color, because CO binds tightly to hemoglobin and prevents the usual deoxygenation-related darkening. Cyanide poisoning produces a similar bright pink-to-red lividity, but for a different reason: cyanide blocks the cells from using oxygen, so the hemoglobin in the blood remains saturated with O₂.

Although livor mortis provides a lot of information to investigators about the nature of an individual’s death, it cannot be the only postmortem sign that coroners rely on. Investigators often use multiple clues, such as body temperature (algor mortis), stiffness of the muscles (rigor mortis) and insects near the area where the body was found (forensic entomology) to calculate PMI. Relying solely on a single postmortem sign would lead to inaccurate results.

How Is Livor Mortis Different From Pallor, Algor, And Rigor Mortis?

Livor mortis rarely tells the whole story on its own. It is one of four classic "mortis" signs a body passes through after death, and forensic teams read them together because each one is driven by a different process running on its own clock. Mixing them up is easy, since the names all share that Latin mortis ("of death"). Here is how they line up:

• Pallor mortis (from Latin pallor, "paleness"): the near-immediate paling of the skin within roughly 15 to 30 minutes of death, as circulation stops and blood drains from the surface vessels. It is the first sign and the most fleeting.
• Algor mortis (algor, "coldness"): the cooling of the body toward its surroundings once it stops generating heat. Under typical conditions a body loses roughly 1.5 °F (about 0.8 °C) per hour, the figure behind the Glaister equation used to back-calculate the time of death.
• Rigor mortis (rigor, "stiffness"): the temporary stiffening of the muscles. It sets in 1 to 2 hours after death, reaches full stiffness around 12 hours, holds for roughly another 12 hours, then fades as decomposition advances.
• Livor mortis (livor, "bluish color"): the gravity-driven pooling of blood described throughout this article, visible from about 2 hours and fixed by 8 to 12 hours.

Because each sign keeps its own timetable, a pathologist who finds, say, no remaining rigor but well-fixed lividity can bracket the time of death far more confidently than any single sign would allow. That is why livor mortis is almost always weighed alongside body temperature, muscle stiffness, and other evidence rather than read in isolation.