Changes in the color of the skin caused by the flow of blood into the underlying surfaces of the corpse (post-mortem redistribution of blood in the corpse) .
Mechanism of formation of cadaveric spots
After the cessation of cardiac activity, blood pressure drops to zero, contraction of blood vessels in the arterial system continues for some time, which leads to overflow of capillaries and small veins; due to gravity, the blood drops, passively expanding the underlying venous vessels and begins to shine through the skin, forming cadaveric spots. They are usually purple in color with a blue tint and are formed by blood deprived of oxygen and containing reduced hemoglobin .
Location of cadaveric spots
The location of cadaveric spots depends on the position of the body of the corpse.
When the corpse is in a vertical position, cadaveric spots are located on the lower extremities, forearms, and hands. When the corpse is positioned on the back, they form on the posterolateral surfaces of the body, with the exception of areas subjected to compression. When the corpse is positioned on its stomach, they form on the front surface of the body (neck, chest, abdomen, lower extremities).
Degree of severity of cadaveric spots
The severity of cadaveric spots depends on the condition and amount of blood. With mechanical asphyxia, cadaveric spots are abundant, this is explained by the liquid state of the blood. With prolonged agony, the slow formation of cadaveric spots, as red and white convolutions are formed. With heavy blood loss, cadaveric spots are weakly expressed and slowly form.
The color of cadaveric spots has important diagnostic value. In case of carbon monoxide poisoning, cadaveric spots are bright red due to the formation of carboxyoglobin. In case of poisoning with methemoglobin-forming poisons (nitrobenzene, berthollet salt, naphthalene, etc.), cadaveric spots acquire a grayish-brown color.
In cases of death from hypothermia and drowning in water, cadaveric spots have a pinkish tint, as the epidermis loosens and oxygen penetrates the blood forming oxyhemoglobin.
When examining cadaveric spots, the forensic expert, in addition to describing the nature, location and color of the cadaveric spots, must establish what stage they are in. To do this, pressure is applied to the cadaveric spot with the palmar surface of the nail phalanx of the index finger in those areas of the body where bone tissue is located under the skin (lumbar region, sternum). The pressure can be produced with a special dynamometer; the pressure force should be 2 kg per 1 square meter. see, pressure duration 3 seconds. The time of restoration of the color of the cadaveric spot is recorded with a stopwatch.
There is a certain pattern in the formation of cadaveric spots, where three stages of development of cadaveric spots are distinguished: hypostasis (cadaveric stains), stasis (stopping , diffusion) and imbibition (impregnation ).
The first stage - hypostasis begins immediately after cardiac arrest, and the earliest appearance of cadaveric spots is already after 30 minutes, if death was not from blood loss and the blood in the corpse is liquid. The duration of the stage is from 8 to 16 hours. Typically, cadaveric spots appear 2 hours after death. Blood, almost unchanged in its properties, is located in the vessels of the underlying parts of the body under the influence of gravity. When you press on the cadaveric spot at this stage, it disappears, the blood is forced out of the vessels and restores its color. On the surface of the cut in the area of cadaveric spots, dilated venous vessels are visible, from which dark red, liquid blood flows.
If the position of the corpse is changed before 12 o'clock, then the cadaveric spots appear again on the underlying parts of the body and disappear on the overlying ones.
The second stage is stasis (diffusion ). The duration of the stage is from 8-12 hours to 24-36 hours. During this period, lymph and intercellular fluid gradually penetrate through the walls of blood vessels into them, gradually diluting the liquid part of the blood (plasma), promoting hemolysis (disintegration) of erythrocytes (red blood cells). Blood also penetrates the wall of blood vessels and permeates the surrounding tissue. Cadaveric spots at this stage do not disappear when pressed, but turn pale and slowly restore their original color. If the position of the corpse is changed 14-16 hours after death, then less intense cadaveric spots will still appear in the underlying sections, but will not disappear where they formed earlier. The second stage may occur earlier than 8 hours with blood loss or later than 16 hours with mechanical asphyxia. A reddish watery liquid flows from the cut surface in the area of the cadaveric spots, and drops of blood slowly flow from the cut vessels.
The third stage is imbibition (impregnation ). It begins to develop 24-36 hours after death by the end of the first day. A fluid consisting of lymph, intercellular fluid, plasma, and hemolysis products permeate soft tissues and skin. Cadaveric spots at this stage do not turn pale or disappear when pressed, but retain their original color and do not move when the position of the corpse changes. On the cut tissue in the area of the cadaveric spot, a pinkish liquid flows from its surface, no blood is released from the cut vessels.
In the internal organs, simultaneously with the appearance of cadaveric spots in the skin of the corpse, a similar picture occurs in the underlying parts of the internal organs (cadaveric hypostases), blood accumulates in the internal organs, giving them a reddish-bluish appearance.
If a person has cadaveric spots but is still breathing, how long will it take for him to die?
Cadaveric stains are areas of body tissue posthumously soaked in blood.
Outwardly, they look like large area bruises. The color of corpse spots,
depending on the color of the blood and its quantity.
perhaps with a slight grayish tint. Immediately after the death of body tissue
still consume oxygen from the blood and therefore all the blood in the circulatory system
system, under the influence of gravity gradually descends into the lower
pressing parts of the body, overflowing mainly the venous part of the bloodstream
To resolve issues of how long ago death occurred based on cadaveric spots,
cadaveric spots. Cadaveric spots go through three stages in their development: hy-
The blood in the corpse is liquid. Clearly cadaveric spots appear after 2-4 hours
after death occurs.
To determine the stage of development of cadaveric spots, use the following
ries, which determine the stage of development of cadaveric spots and, accordingly,
but the time of death.
is located. After the pressure stops, blood fills the vessels again
after some time, the cadaveric spots are completely restored. At
called the stasis stage. As a rule, pronounced manifestations characteristic
for this stage, are noted 12 hours after the onset
of death. At this stage, the overstretched walls of blood vessels become more
permeable and through them the exchange of fluids begins, which is not typical for
additives inside them and mixed with the blood, they contribute to hemolysis (decomposition
When the position of the corpse changes during this period of time, the cadaveric spots are
accurately move to those parts of the body that become underlying, and
The timing of death, determined by the nature of changes in cadaveric spots - 1998.
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Analysis of the results of mathematical processing showed that the experimental data reject the hypothesis about the distribution of dynamometry data according to the normal law. Therefore, a specific digital gradation of dynamometry indicators for the corresponding intervals of the postmortem period as an independent diagnostic test in forensic medical practice is unacceptable.
Podolyako V.P. Diagnostic capabilities of dynamometry indicators when deciding the issue of how long ago death occurred “Forensic medical examination.” –M., –1998, 1. –p. 3–6.
During dosed dynamometry of cadaveric spots, the research conditions are strictly standardized. The surface area of the dynamometer in contact with the skin of the cadaveric spot is 1 cm 2. Pressure is applied with a force of 2 kgf/cm 2 for 3 s. The dynamometer should be positioned perpendicular to the surface of the skin. When cadaveric spots are localized on the posterior surface of the body, pressure is applied in the lumbar region along the midline, and when cadaveric spots are located on the anterior surface of the body, pressure is applied along the midline of the sternum body. The time for color restoration of cadaveric spots is recorded using a stopwatch. Under these conditions, as the author (V.I. Kononenko) notes, the accuracy of determining the duration of death does not exceed ±2–4 hours.
Cadaveric spots (lat. livores mortis) appear after death on the underlying parts of the body and are a sign of the onset of biological death. They belong to early cadaveric phenomena and represent areas of skin most often bluish-violet in color. Cadaveric spots appear due to the movement of blood through the vessels to the lower parts of the body under the influence of gravity (photo 2, 3).
Those areas where the corpse comes into contact with the surface of the bed on which it lies remain pale because the blood is squeezed out of the vessels. Folds of clothing leave imprints in the form of pale stripes against the background of cadaveric spots.
Appear 2-4 hours after cardiac arrest.
The hypostasis stage is the initial stage of the development of the cadaveric spot, it begins immediately after the cessation of active blood circulation and ends after 12-14 hours. At this stage, cadaveric spots disappear when pressed. When the position of the corpse changes (turns over), the spots can completely move to the underlying sections.
Stage of stasis or diffusion - cadaveric spots begin to move into it approximately 12 hours after the onset of biological death. At this stage, gradual thickening of the blood in the vessels occurs due to the diffusion of plasma through the vascular wall into the surrounding tissue. In this regard, when pressed, the cadaveric spot turns pale, but does not completely disappear, and after some time it restores its color. When the corpse's position changes (turns over), the spots may partially move to the underlying sections.
Stage of hemolysis or imbibition - develops approximately 48 hours after the moment of biological death. When pressing on the cadaveric spot, there is no change in color, and when turning the corpse over, there is no change in location. In the future, cadaveric spots do not undergo any transformations other than putrefactive changes.
Tissue fluids accumulating in the underlying parts of the corpse penetrate the blood vessels, thin the blood, causing hemoglobin to leach from red blood cells. The hemoglobin-stained liquid evenly stains the tissue.
In the overlying parts of the corpse - on the chest, neck, face, abdomen and limbs, where the blood in the vessels has become thicker from loss of fluid, the processes of imbibition with such “concentrated” blood occur along the vessels and are reflected in the appearance after 3-4 days (at an average temperature 15-23°) on the skin of a putrefactive venous network: branching dark purple figures, putrefactive networks, which are a pattern of saphenous veins.
Cadaveric spots may be mixed in some cases with bruises. You can distinguish a cadaveric spot from a bruise either by pressing on it with a finger, causing the cadaveric spot to turn pale, but the color of the bruise does not change, or by making an incision in the area being examined with a belt. On a section of a cadaveric spot, the skin and tissue are uniformly colored lilac or faint violet. Droplets of blood protrude from the cut vessels, easily washed off with water; the tissue on the cut does not differ in any way, except for color, from the cut on pale areas of the skin. When a bruise is cut, the blood that has leaked from the vessels during life is released in the form of a dark red limited area that is not washed off with water. In later stages of imbibition, pressure no longer causes blanching of the cadaveric spot, and pronounced bloody impregnation of the tissue smoothes the boundaries of existing bruises and can itself lead to mixing of such imbibited areas with the bruise. The microscopic picture of the cadaveric spot does not represent anything characteristic and does not differ from unpainted areas of the skin.
Against the background of cadaveric spots, post-mortem small and large hemorrhages can form both in the skin and in deeper tissues from swelling of the blood and subsequent rupture of blood vessels. They should not be confused with intravital ecchymoses. When T. is positioned on the back, they can be found in the soft tissues of the occipital region, back, and neck; in the reverse position - in the muscles of the neck and chest. Such hemorrhages are especially pronounced in asphyxial death, and can give rise to their confusion with intravital bruises. Post-mortem hemorrhages can occur due to organ trauma, for example, when the myocardium is pulled with tweezers; due to rigor mortis of the muscle, blood from damaged vessels is easily squeezed out here, giving something like hematomas. Hypostasis of internal organs can be mistaken for a pathetic state. processes; in the meninges, cadaveric injection of blood vessels—for hyperemia; in the lungs - for hemorrhagic pneumonia, heart attacks, and in infants - for atelectasis; hypostasis of the pancreas and its imbibition—for hemorrhagic pancreatitis. Posthumously, ecchymosis can also occur under the serous integument—peritoneum, pleura, epicardium. Intravital formation of ecchymosis is observed in rapidly occurring deaths—asphyxia, injuries, sudden death (in the conjunctiva, under the pleura, epicardium—Tardier spots, in the soft tissues of the skull, the tissue surrounding the esophagus and larynx in their upper parts, and other places). And intravital ecchymoses are sometimes so extensive that they can be mistaken for bruises resulting from violent impact on the tissue.
They are a reliable sign of death: none of the intravital processes can imitate cadaveric spots. The appearance of cadaveric spots indicates that circulatory arrest occurred at least 1 hour ago.
The location and movement of cadaveric spots is of great forensic medical importance; it allows one to judge the position in which death occurred, whether the position of the corpse changed after death, etc. If the position of the corpse did not change in the interval between the onset of death and the examination of cadaveric spots, cadaveric spots are localized in those parts of the body that are located closer to the center of gravity. If after death the position of the corpse changed, then the position of the corpse and the location of the hypostases may not correspond to each other.
The movement of cadaveric spots occurs as long as the blood is in the vessels and the processes of imbibition have not developed sufficiently.
Cadaveric spots in the first 4-5-7 hours. after death occurs, when the corpse is turned over, they can disappear completely and appear in a new place. After 12-15 hours. a change in the position of the corpse is accompanied only by the blanching of the cadaveric spots, and the cadaveric spots that appear in new places are also pale. By the end of the day, new cadaveric spots no longer appear. The movement of cadaveric spots stops depending on the onset of the imbibition process.
What matters is their degree of expression; and color. Because the formation of cadaveric spots depends on the swelling of the blood, then the amount of blood in the corpse and its condition will affect their size. So, with a quick death, when the blood remains liquid, the cadaveric spots will be sharply expressed and occupy a large surface. bodies. In death, accompanied by blood clotting in T., they will be less pronounced. Excessive external and internal bleeding before death can even lead to the complete absence of cadaveric spots in some cases. There are weakly pronounced cadaveric spots on the corpses of people who died from debilitating diseases or anemic people. The usual color of cadaveric spots—blue-purple, purple—depends on the fact that hemoglobin in cadaveric blood is contained in the form of reduced hemoglobin due to the absorption of oxygen by tissues in the first hours after death. But if T. lies in a damp, damp place (in ice, snow, a damp room), then the macerated epithelium becomes permeable to air oxygen, the reduced hemoglobin turns into oxyhemoglobin and the cadaveric spots take on a pink-red color.
The color of cadaveric spots also changes due to the action of certain blood poisons that convert hemoglobin into other compounds (Carboxyhemoglobin, methemoglobin).
Previously it was believed that the nature of the change in the cadaveric spot under pressure allows forensic experts to establish the duration of death. When analyzing the behavior of a cadaveric spot, it is necessary to take into account the cause of death, the rate of its onset (acute or agonal), and the research methodology. Fairly approximate results can be obtained by applying finger pressure on the spot, so standard methods with a dosed area and pressure force have been developed. Pressure is carried out using a standard calibrated dynamometer. The author of the method is V.I. Kononenko, based on the research carried out, proposed tables [2] for determining the duration of death based on the results of dynamometry of cadaveric spots. The error of the method, according to the author, is within ±2 - ±4 hours. The lack of indication of the confidence interval of the error is a significant drawback of the technique, which reduces its significance for practical application.
However, further analysis of the results of mathematical processing showed that the experimental data reject the hypothesis about the distribution of dynamometry data on cadaveric spots according to any mathematical pattern. Therefore, a specific digital gradation of dynamometry indicators for the corresponding intervals of the postmortem period as an independent diagnostic test in forensic medical practice is unacceptable. Cadaveric spots are formed under the influence of many factors; this process is individual both for a specific corpse and for the area where the spots are localized [3] [4].
Currently, there are no scientifically based methods for determining the duration of death based on the state of cadaveric spots. The time it takes for the color of cadaveric spots to recover after pressing on them can only be used for an approximate assessment of how long ago death occurred when examining a corpse at the place of its discovery.
Early cadaveric phenomena
Early cadaveric phenomena include cooling, rigor, cadaveric spots, drying out, and clouding of the cornea.
After death, the temperature of the corpse immediately begins to drop due to the cessation of oxidative processes in the body: cadaveric cooling occurs. The speed and extent of it depends on many factors - ambient temperature, humidity, air movement, the surface on which the corpse lies (wood, iron, etc.), the presence and quality of clothing, as well as on the individual characteristics of the corpse itself (degree of fatness , body temperature at the time of death).
On exposed parts of the body, the cooling of the corpse usually becomes noticeable an hour or two after death; in places covered with clothing, after four to five hours.
However, these data are only of relative importance for establishing the duration of death, since they, depending on the above reasons, are subject to wide fluctuations.
Cooling of the body, perceptible to the touch, cannot in itself serve as a reliable sign of the actual occurrence of death, since in living people, in some painful conditions, a significant decrease in temperature is also observed.
Rigor mortis is expressed in the fact that both the skeletal muscles and the muscle tissue of the internal organs become denser, shortened, as if tense, and become “stiff.” As a result, the joints of the body and limbs appear to be “frozen” in a certain position, often fixing the position that the person took at the time of death (unless it was soon changed). It takes some effort to reposition stiff joints. If such an effect on a numb muscle is carried out in the first four to five hours after death, then rigor can recover and fix the joint in the new position that was given to it. This should be kept in mind in order to avoid making a mistake when judging the initial position of the corpse. In particular, there are cases when a criminal, wanting to stage suicide, put a weapon in the victim’s hand; the rigor that followed fixed him in this position. It appeared that the deceased was holding a weapon at the time of death.
There is a certain pattern of the occurrence and development of rigor mortis of skeletal muscles. It arises first in the muscles of the head, face (primarily in the muscles of the lower jaw) and neck, then successively descends down to the trunk and lower limbs and, finally, spreads to the upper limbs. However, this scheme is not constant; deviations are possible here.
In the lower jaw, rigor usually develops two to four hours after death, and after six to eight hours it can be observed throughout the body.
After a certain time, rigor mortis disappears, and its so-called resolution occurs. Typically, resolution begins on the second and ends on the third or fourth day after death. It occurs in the reverse order in relation to the development of rigor, that is, from bottom to top.
The forensic medical significance of rigor mortis also lies in the fact that it is a completely reliable sign of actual death and, in addition, the degree of its development can serve as one of the criteria for determining the time of death, and sometimes its cause. However, the speed and degree of development of rigor mortis are not absolutely stable; they depend on a number of conditions, both external and individual. Thus, the higher the temperature of the external environment, the faster and more intensely rigor mortis develops (and resolves). There are cases when it is sharply expressed in all muscles within two to three hours and resolves seven hours after death. At low ambient temperatures, the onset of rigor mortis and its resolution are delayed. Naturally, under such conditions, all factors influencing the cooling of the corpse will also have an effect on the development and resolution of rigor mortis.
Rigor rigor occurs faster and is more sharply expressed with well-developed muscles and, conversely, is less pronounced with insufficient muscle development, for example, in emaciated subjects, in infants, the elderly, and with muscle atrophy. The degree of muscle tension at the moment of death is of great importance. So, if death occurs due to symptoms of convulsions (for example, during an epileptic seizure, electric shock, strychnine poisoning), a very sharp rigor quickly sets in.
Thus, the diagnostic value of rigor mortis as an indicator of the time of death is only of relative importance.
It should also be said about the so-called fatty mortis, which has nothing to do with cadaveric mortis. As a result of a decrease in body temperature, subcutaneous fat hardens and becomes denser; The elasticity of the skin and subcutaneous tissue decreases, the existing folds in the skin do not straighten out and can be mistaken, for example, on the neck for a trace of pressure from a loop.
When the activity of the heart stops, the blood in the bloodstream flows under the influence of gravity into the lower parts of the body, causing overflow and dilation of the corresponding vessels. The latter, shining through the skin, form cadaveric spots. Their color can be different - reddish, purple, bluish or purple. There are three stages of cadaveric spots. The first - hypostases - are dilated, blood-filled vessels. They appear 20 - 45 minutes after death on the lower parts of the corpse (when lying on the back, usually on the posterolateral surfaces of the neck). After an hour or two, they increase in size and become more intense, in some places they even merge and appear in different areas of the body. Against their background, those places where the skin was pressed by folds of clothing or the weight of the body to the surface on which the corpse lies (on the buttocks, shoulder blades, back of the head) stand out sharply with their pallor. Hypostases easily disappear when pressed with a finger; when the corpse is turned over, they disappear and are re-formed in those places that happen to be located below.
After two to three hours after death, the hypostases are gradually replaced by the second stage of spots - cadaveric stases. They are characterized by even greater congestion of the vessels, sometimes by small ruptures with the formation of pinpoint hemorrhages; the blood can no longer be completely squeezed out. Therefore, even with strong finger pressure, the stain only fades, but does not disappear. When the corpse is turned over during this period, the existing spots do not disappear, but new hypostases appear in those parts of the corpse that are located below.
The third stage of stains - corpse impregnation (imbibition) - occurs approximately ten hours after death (sometimes much later). At this time, blood pigment (hemoglobin) is released from red blood cells into the blood plasma and, together with it, seeps through the walls of blood vessels into the surrounding tissue, saturating it, turning it red. Such an imbibed spot does not fade when pressed and does not disappear when the corpse is turned over.
Cadaveric spots are of great forensic importance. Their color sometimes indicates the cause of death (in some poisonings and death from low temperature). The presence of stasis and cadaveric impregnation on the upper parts may indicate that the corpse was turned over. And finally, they allow one to draw conclusions about the duration of death, but one must be very careful, since the speed and degree of development of cadaveric spots depend not only on the time factor, but also on other reasons. In a warm environment, spots form faster; in cold conditions, their appearance and the transition from one stage to another are significantly delayed. The properties of the blood (liquid, clotted) matter. Cadaveric spots may be very weakly expressed or absent if the corpse is significantly bled. They can be especially sharp in those parts of the body where there was great plethora at the time of death (for example, on the face during hanging, strangulation).
Cadaveric spots appear not only on the external surfaces, but also on internal organs, where they can be mistaken for painful changes (for example, inflammatory phenomena). Corpse impregnation is especially pronounced on the inner surface of the vascular walls and heart.
With the cessation of blood circulation, the flow of fluid to the body tissues stops, and, consequently, the compensation for its loss due to evaporation stops. In addition, as indicated, there is an outflow of fluid from the higher located parts of the corpse. The consequence of this is depletion of fluid, drying of tissues, especially noticeable on the integument of the body and, in particular, where the epithelial layer is thin or damaged for some reason (intravital or postmortem). Dried areas first acquire a yellow, then brownish color, their surface is dense, reminiscent of parchment. In the corpses of adults, drying appears on the mucous border of the lips, in men - on the scrotum, on the foreskin.
The eyeballs also dry out; with open eyes, the dried part repeats the shape of the palpebral fissure, forming two brownish triangular areas on the tunica albuginea, on both sides of the iris, the so-called “Larchet spots,” which usually appear by the end of the first hour after death. Approximately 24 hours after death, the cornea becomes cloudy and becomes whitish and opaque. Further drying of the eyeballs leads to their loss of elasticity, wrinkling and retraction.
Due to the drying of the damaged surface horny skin (epidermis), abrasions, scratches, scratches, etc. that existed during life become more distinct and seem to increase in size; the same thing happens with post-mortem injuries, for example, during transportation of a corpse. Areas of skin diaper rash take on the appearance of abrasions (in the genital area or where there was weeping eczema), which can lead to erroneous conclusions about the violence caused. Traces of vomit drips around the mouth due to the presence of acidic stomach contents, which loosen the stratum corneum of the skin; when dried, they can imitate the result of the action of caustic liquids, which sometimes leads to an erroneous suspicion of poisoning. Drying is especially noticeable on the corpses of newborns and infants. This is explained by the tenderness of their epithelial cover, its low resistance and slight vulnerability.
From the foregoing it follows that early cadaveric changes are subject to significant fluctuations in each individual case and it is impossible to resolve the issue of how long ago death occurred on the basis of any one sign. Only a thorough analysis of the totality of the data obtained, taking into account the characteristics of the entire specific situation, allows us to draw more or less reliable conclusions.
violet-bluish or purple-blue, depends on many reasons, primarily
Immediately after death, the skin of a human corpse is pale,
the topic takes on a venous character. Cadaveric spots are formed due to
the fact that after circulatory arrest, the blood contained in the blood vessels
th channel. Blood translucent through the skin gives it its characteristic
movements of the corpse and others must represent developmental processes
postasis, diffusion and imbibition.
Hypostasis is the stage at which the blood descends to the underlying sections
bodies, overflowing their vascular bed. This stage begins immediately after
circulatory arrest, and the first signs of skin coloring may
but observe after 30 minutes if death was without blood loss, and
technique: press on the cadaveric spot, if there is a cadaveric spot at the point of pressure
completely disappears or at least turns pale, then measure the time after which
when the original color is restored. (Fig. 24-2) Fact of change
(no change) in the color of the cadaveric spot and the time of its recovery are critical
Cadaveric spots in the hypostasis stage completely disappear when pressed,
due to the fact that the blood only fills the vessels and easily flows through them
changing the position of the corpse at this stage of development of cadaveric spots, they
completely moved to new places, in accordance with which departments
the bodies became underlying. The hypostasis stage lasts on average 12-14
The next stage in the formation of cadaveric spots is the stage of diffusion, which is still
Lymph and intercellular fluid gradually penetrate through the walls of the vessel
du, dissolution) of red blood cells. The liquid part of the blood also penetrates through
the walls of blood vessels and permeates the surrounding tissues. As a result of these pro-
when the blood thickens. In the stage of diffusion when pressing on cadaveric
the spots do not disappear completely, but only fade after a while
restore their color.
Full development of this stage occurs within 12 to 24 hours.
partially remain in the old place due to saturation of the tissues surrounding
Cadaveric stains are areas of body tissue posthumously soaked in blood. Outwardly, they look like large area bruises.
The color of cadaveric spots, violet-bluish or purple-blue, depends on many reasons, primarily on the color of the blood and its quantity. Immediately after death, the skin of a human corpse is pale, perhaps with a slight grayish tint.
Immediately after death, body tissues still consume oxygen from the blood and therefore all blood in the circulatory system acquires the character of venous.
Cadaveric spots are formed due to the fact that after circulatory arrest, the blood contained in the circulatory system, under the influence of gravity, gradually descends into the underlying parts of the body, overflowing mainly the venous part of the bloodstream. Blood shining through the skin gives it a characteristic color.
To solve the issues of how long ago death occurred, the movement of the corpse, and others, it is necessary to understand the development processes of cadaveric spots. Cadaveric spots go through three stages in their development: hypostasis, diffusion and imbibition.
Hypostasis is the stage at which blood descends into the underlying parts of the body, overflowing their vascular bed. This stage begins immediately after circulatory arrest, and the first signs of coloration of the skin can be observed within 30 minutes, if there was no blood loss and the blood in the corpse is liquid. Clearly cadaveric spots appear 2-4 hours after death.
To determine the stage of development of cadaveric spots, the following technique is used: press on the cadaveric spot; if at the point of pressure the cadaveric spot completely disappears or at least turns pale, then measure the time after which the original color is restored. The fact of change (non-change) in the color of the cadaveric spot and the time of its restoration are the criteria by which the stage of development of cadaveric spots and, accordingly, the time of death are determined.
Cadaveric spots in the stage of hypostasis completely disappear when pressed, due to the fact that the blood only fills the vessels and easily moves through them. After the pressure stops, blood fills the vessels again after some time and the cadaveric spots are completely restored. When the position of the corpse changes at this stage of development of cadaveric spots, they completely move to new places, in accordance with which parts of the body have become underlying. The hypostasis stage lasts on average 12-14 hours.
The next stage in the formation of cadaveric spots is the diffusion stage, also called the stasis stage. As a rule, pronounced manifestations characteristic of this stage are noted 12 hours after death. At this stage, the overstretched walls of the vessels become more permeable and an exchange of fluids begins through them, which is uncharacteristic of a living organism. Lymph and intercellular fluid gradually penetrate through the walls of blood vessels into them and mix with the blood, they contribute to hemolysis (disintegration, dissolution) of red blood cells. The liquid part of the blood also penetrates the walls of blood vessels and permeates the surrounding tissues. As a result of these processes, the blood thickens. In the diffusion stage, when pressure is applied to cadaveric spots, they do not disappear completely, but only turn pale, and after a while they restore their color.
Full development of this stage occurs within 12 to 24 hours. When the position of the corpse changes during this period of time, the cadaveric spots partially move to those parts of the body that become underlying, and partially remain in the old place due to the saturation of the tissues surrounding the vessels.
Source: only the dead have cadaveric spots