What is Pallor Mortis?

In the chemistry lab, understanding of kinetics is used to both measure and change the death timeline. Especially this is for measuring time of death and preserving evidence after death. There are two general methods by which researchers determine the time of death, and they are as follows:

1. Ratio method: In this method, time of death is estimated by evaluating the presence / absence of an indicator in the deceased person in relation to the known behavior of such indicators.

2. Synchronization method: In this method, the time of death is estimated by evaluating the events occurring at or near the death event or by providing information indicating a time period for the death event.

In each type of determination, the word predictive is used to describe the method. Because despite all the advances made in science, time of death is still one of the least reliable methods available. There are so many variables that can skew the results to be an exact science.

The first steps in determining the time of death are as follows:

1) Gathering the body

2) Collection of evidence around the body

3) Collecting information about the deceased

What is Pallor Mortis?

Pallor Mortis or death pallor, pallor that occurs in the body after death is rapidly seen in light-colored white-skinned people and occurs because of insufficient capillary blood circulation. Thus, blood accumulates in the lower parts of the body and this creates Pallor Mortis. This event develops approximately 15 minutes to 2 hours after death, and this is the first sign of death due to lack of circulation. Also, expressions such as deadly pale are used in the English language to characterize someone’s appearance (such as a zombie or a vampire). In addition to serving as a linguistic identifier, skin color changes occur after a death called Pallor Mortis. It often helps forensic professionals to assess the time of death, also referred to as post-mortem time PMI.

However, pale skin is more noticeable in those with lighter skin tones, especially red skin, and is less common for darker skin types. There are also slight differences in skin color between the two sexes, but this difference disappears as a result of pallor mortis.

What Causes Pallor Mortis?

Pallor Mortis is caused by a lack of capillary circulation. Clinical death is when the heart stops beating. Without a heartbeat, blood cannot reach every part of the body, especially organs farther from the heart, such as the skin. The capillaries in the dermis (the second skin layer after the epidermis) and the hypodermis (the third and deepest layer of the skin) stop receiving a new oxygenated blood supply, and the oxygen-associated hemoglobin has a bright red color.

Without the heart’s power to pump blood to the body, the blood in the blood vessels stagnates and the cells in the blood, red blood cells (such as RBCs) begin to move in the direction where gravity is strongest. While there is a pale color in the areas where the blood moves away, a reddish pink color develops in the areas where the blood accumulates. The second phenomenon is called vitality and becomes visible about 2 hours after death.

How Do Forensic Specialists Use Pallor Mortis to Determine PMI?

Post-mortem interval, or time since death, estimates how much time has passed between an individual death and the body discovered. Forensic experts calculate the time of death using various post-mortem clues. Pallor Mortis is the first post-mortem stage of death. In an article published in 2000, the usefulness of Pallor mortis in detecting PMI was evaluated. The researcher used an octo-electronic colorimeter to measure the color change in 126 bodies. They concluded that because pallor mortis is developing rapidly, it is not the most useful visible change for determining approximate time of death. The degree of pallor does not change significantly over time and does not give clues about the cause of death.

Forensic scientists often prefer to use other changes to determine PMI, often using information from more than one factor to estimate a range. They look at how much decomposition progresses using muscle rigidity (rigor mortis), body temperature, and the presence or absence of certain insects. While pallor mortis is not very useful for forensic professionals, it is useful for detecting a person in a crowd.

Decomposition

The decomposition stages are well known and can be used as a rough guide for death time, especially in bodies that are absent for weeks or even months. Rigor, Livor, and Aldor Mortis are listed as stages of dissociation while all occur 1-48 hours after death. The later stages of decomposition should be used as an estimate after the 48 hour window. There are two main ways the body decomposes; autolysis and putrefaction. Both of these processes occur by chemical reaction so both are subject to the typical kinetic controls of a chemical reaction.

Autolysis is the process by which digestive enzymes inside body cells break down carbohydrates and proteins. Decay is the predominant cause of tissue degradation and is dependent on bacterial activity. Decay begins 4 to 10 days after death, and most of the appearance of a dead body over time is due to decay:

• Bloating
• Green discoloration of the abdomen
• Marbling through the blood vessels – a brown-black discoloration of blood vessels caused by hydrogen sulfide gas
• Blisters and skin drifting
• Hair and nail loss

In an environment where overheating, a disease such as peritonitis where excessive bacteria are already present, or where external bacteria are high, such as sewage, decay occurs quickly. Cooling the body can slow rotting and freezing can stop completely. There are four general stages of decay:

• Decay (4-10 days after death) Autolysis occurs and gases (odor) and discoloration begin.

• Skin that is exposed to black rot (10-20 days after death) turns black, swelling subsides and fluid is released from the body.

• Butyric fermentation (20-50 days after death) the remaining meat is removed, butyric acid residues ferment and if the body comes into contact with the soil, it will start to mold.

• Dry Decay (50-365 days after death) Rotting is very slow due to the drop of liquid, hair and nails.

The degree of decay allows researchers to roughly estimate the time of death against this timeline, but still large time intervals should be noted.

Flora and Fauna

Plants and insects are often used to estimate time of death. Through observation at a crime scene, it is often possible to know how long a body has been there. For example, the grass that the body touches will gradually wither and die. The death rates of certain types of grass when covered are actually known, and taking a sample of the lawn to a botanist can give it time to shed if the person is killed in that scene, or if the body is shed. Or he can detect that he was killed elsewhere and brought there.

Insects, particularly flies, rapidly infect an unprotected body and have a well-understood timeline that can be used to determine the time of death (when gross) worm formation. Taking existing maggot samples to an entomologist (insect doctor) helps to accurately determine the time of death, assuming the flies can reach the body immediately after death.

Stomach Content

Food in the victim’s stomach can give an approximate death time, depending on the degree of digestion that occurs.

Vitreous Potassium

One way to predict the time of death is by determining the Vitreous (eye fluid) Potassium concentration. Potassium (K) is a nutrient that helps maintain the balance of electrical charges inside and outside of cell membranes in the body. Intracellular potassium concentration is 40 times higher in intracellular fluids than blood. After death, the amount of potassium inside and outside the cell membrane begins to equalize at a steady rate. This can be read from the potassium concentration from an intracellular fluid after death. And this reading means it can detect the time of death more accurately than the methods mentioned earlier. The vitreous fluid of the eye is the fluid most commonly used for this test, if available. Test results are most accurate 1 to 12 hours after death.

The equation used to determine the death time according to the 0.14 milligram potassium leakage rate Equivalent / Liter / hour:

(7.14 × K + concentration) -39.1 = hours since death (7.14xK + concentration) -39.1 = hours since death

The leak rate of potassium is not the same for all regions of the world, and coroners have charts that help determine the correct leak rate for their area.