How to guess the time of death

1. Lividity: Lividity usually appears 2-4 hours after death, but it can also appear as early as 30 minutes and as late as 6-8 hours. The emergence and development of necrophilia can be divided into three stages: 1. Decline period; It usually occurs 2-4 hours after death, and there are lavender 8 | 1 u( U# I7 b. T) red spots, strips or patches on the lower part of the body. Gently press with your fingers, the color will fade, and after the pressure is released, lavender will appear again. If the corpse is turned over during this period, the original corpse spot can disappear, and in the new lower part, new corpse spots will gradually form. 2. Dilatation period: Tissue fluid also sinks to the lower part of the corpse like blood, and the tissue fluid deposited around the blood vessel penetrates into the blood vessel through the blood vessel wall, and mixes with blood to promote hemolysis. Plasma is diluted by tissue fluid, stained with hemoglobin, and begins to seep out of blood vessels, which is the diffusion period. Generally, it takes 65,438+02 hours (at least 8-65,438+00 hours) for necrophilia to spread. At this stage, the lividity has merged into a large area, showing a diffuse purplish red. Gently press with your fingers, which is not easy to fade. After the corpse is turned over, the original corpse spot is not easy to fade, and the new lower part is not easy to form new corpse spots. 3. Infiltration stage: Lividity develops to infiltration stage about 24 hours after death. At this stage, the liquid stained with hemoglobin penetrates into the tissue to stain the tissue and cells. The lividity is obvious, deep purple, and the finger pressure does not fade. When the corpse is turned over, the original corpse spot does not fade and no new corpse spot appears. The infiltration period lasts for a long time, and then it turns into corruption. Check the corpse spot, and consider the cause of death at the same time, because it is closely related to the strength of the corpse spot. For example, the corpse spot in patients with massive bleeding appears late and not significant; Body spots appear early and thick. :w ' @)} & amp； | 9u .[6z ^/ m； Me, s & ampY & ampJ 2. Stiff: Stiff usually occurs at 1-3 hours after death, a few at 10 minutes after death, and some at least at 7-8 hours after death. The occurrence of rigor mortis usually has a certain order, mostly from top to bottom, that is, the so-called descending type, starting from the masseter and neck muscles, followed by the facial muscles, and then the trunk, upper limbs and lower limbs. At the time of autopsy, if the mandibular joint begins to appear rigor mortis, it is usually within L-3 hours after death (occasionally 7 hours after death, rarely 16- 18 hours); Upper limb stiffness is 5-6 hours after death; Necrosis of lower limbs is 7 ~ 8 hours after death; It has been more than 9 hours since the whole body was stiff and died; After half a day, they are all strong. The whole body is stiff and highly strong, reaching its peak, which is about one day and one night after death. Within 6-8 hours after death, if external force is used to eliminate it, rigor mortis can reappear, but after 8-9 hours after death, rigor mortis will not reappear. 1-2 After a day and night or more, rigor mortis begins to ease, muscles become soft, and joints can rotate slightly. After 2-3 days, all the muscles are softened and the joints can rotate. Generally speaking, the mandibular joint stiffness began to ease, more than 24 hours after death; It has been more than 30 hours since the upper limb stiffness began to relieve after death; Lower limb stiffness was relieved more than 36 hours after death; The whole body stiffness was completely relieved and disappeared for 3-7 days after death. Except for man-made destruction such as carrying corpses. Stiffness of myocardium and smooth muscle also occurs after death, usually starting from 1-3 hours after death and generally lasting 1 ~ 2 days and nights. Because the myocardium is stiff, the blood in the heart cavity is squeezed out, especially in the left ventricle. So the left ventricle is often hollow. In patients with myocardial degeneration, rigidity does not appear, and even if it does, it is weak. Smooth muscles such as the hair muscles of the skin are stiff, and the hair follicle mouth is raised to make the skin look like goose skin (more common in thighs, waist and buttocks); Stiffness of iris muscles can narrow the pupil slightly. Intestinal smooth muscle contracted due to rigor mortis, peaked at 5 hours after death and relieved at 9 hours. * ^&； n(s(| $ R4 s)u 1 s6k ^0 v % h+y； ]7 l Third, the corpse is cold: although the temperature of the corpse drops regularly after death, the temperature of the corpse is -F6 D&t 1v $ u. D' m, and its speed is affected by many factors such as environmental temperature, clothes, age, fatness and death. When the ambient temperature is high, the corpses are covered with cotton-padded clothes or quilts. Mature people, obese people, or people who died of high fever, their corpses cool slowly. On the contrary, if you wear a thin cover or are naked, the ambient temperature is low, you are old and thin, and you die of a long-term chronic wasting disease, and the body will be colder faster. Generally speaking, when the ambient temperature is 16 ~ 18 degrees Celsius, the corpse temperature drops by about L degrees Celsius (0.5- 1.5 degrees Celsius) every hour in the first 10 hour, and then the rate of decline gradually decreases. In the ice and snow, the body completely cooled down 1 hour. It is not accurate to estimate the time of death by measuring axillary temperature with ordinary thermometer, but it is more reliable to measure rectal temperature. It is reliable and accurate to measure the temperature of cerebellopontine cistern with a special thermometer because it is not affected by the environment. Generally, a highly accurate result can be obtained by measuring the body temperature within 14 hours after death. & ampZ "G7L5t # r, k $ a *] 1A5x/p $ r.e) q IV. Local dryness: leathery appearance appears on oral mucosa, scrotal skin or epidermis, with a thickness of 5x&; |7 |6 f5 L/ o% @ is more than 2 hours after death, with obvious cortex, dryness, hardness and dark brown, at least 8- 12 hours after death. /u3l & amp； E9 D* | V. Corneal opacity: After death, corneal transparency gradually decreases. At normal room temperature, mild corneal opacity occurred more than 6- 12 hours after death; Local or diffuse corneal opacity, but the pupil is still recognizable, which is 18 hours-1 day after death; The cornea is obviously turbid with white spots, and the pupils are unrecognizable, mostly 2-3 days after death. 6. Corruption: The speed of corpse corruption is greatly influenced by environmental temperature, cause of death and personal physique. In human body, the ileocecal part is easy to accumulate feces, so it decays earlier after death and produces more hydrogen sulfide, so the corpse green first appears in the right lower abdomen. Carcass green is usually at the end of the first day and night) i I) @* _. M3 J & amp； G+ ]' |$ W began to appear, and then gradually expanded, spread to the whole abdomen, and then spread to the whole body. Generally speaking, the corpse decays fastest in summer, and the corpse green begins to appear in the right lower abdomen, which has exceeded 24 hours after death; If the body is dead for more than 3 days, it is a macro view; After death 15 days or so, the whole body soft tissue rotted, disintegrated, collapsed and digested. Bodies will slowly decompose in winter, even in the ice and snow. When the factors are favorable for the development and reproduction of bacteria, the corpse will rot quickly; Otherwise, slow down or stop. The temperature is 25 ~ 35 degrees Celsius, the humidity is suitable, and it will rot quickly under the condition of air circulation. The experiment shows that the time ratio of the corpse to the same degree of corruption in air, water and underground is 1: 2: 8. In addition, the speed of corpse decay is also related to physical condition. For example, the bodies of young children have more water, the bodies of asphyxiation and sudden death are fluid because of blood, and the dead of septicemia rot faster because of the existence of a large number of bacteria. 4 s