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Warm-Up

Warm-Up. On a dark night Harish and Priyanka were sitting together. Harish was watching movie while his wife Priyanka was reading mystery book. Suddenly, the power went out and Harish decided to go to bed, but strangely Priyanka kept on reading. 

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Warm-Up

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  1. Warm-Up On a dark night Harish and Priyanka were sitting together. Harish was watching movie while his wife Priyanka was reading mystery book. Suddenly, the power went out and Harish decided to go to bed, but strangely Priyanka kept on reading.  There was no artificial light around, Priyanka kept on reading. How come?

  2. Forensic Pathology Death: Meaning, Manner, Mechanism, Cause, and Time Our Day Begins When Your Day Ends

  3. Alive or Dead? • How do you know someone is dead or alive? • Make a two column chart and label it “Death or Alive” and write as many characteristics as you can.

  4. Before and After Death • Before death: ante-mortem • Moment of death: agonal period, peri-mortem • After death: post-mortem • Determination of Post Mortem Interval (PMI)

  5. Hipostasis (Livor Mortis or Lividity) • The discoloration of the body after death due to the gravitational settling of blood. • Can begin around 30 minutes after death • The skin gets purple and waxy • The lips, finger- and toe-nails fade to a pale color or turn white as the blood leaves. • The hands and feet turn blue • The eyes start to sink into the skull

  6. Time of Death—Livor Mortis The Color of Death • Lividity—With decomposition, blood seeps down and settles in the lower parts of a body • Red blood cells turn bluish-purple

  7. Time of Death—Livor Mortis • Lividity typically begins about two hours after death • Discoloration becomes permanent after eight hours • Ambient temperature affects the speed of decomposition • Lividity can determine the position of the body during the first eight hours • Dual lividity could occur if the body was kept in one position two hours after death and then moved to a second position before the lividity became permanent.

  8. Questions: 1. What factors could affect livor mortis? 2 How a criminal might be able to disguise the time of death by controlling the ambient conditions that affect livor mortis.

  9. Questions and Answers 1. What factors could affect livor mortis? Ambient Temperature (warm=faster) (cold room=slower) Anything impeding flow of blood (tight belt or wristwatch) 2. How a criminal might be able to disguise the time of death by controlling the ambient conditions that affect livor mortis. Accept logical answers –Freezer, Trunk of car

  10. Time of Death—Rigor Mortis Live muscle fibers slide back and forth After death, muscle fibers become locked in a flexed position

  11. Time of Death—Rigor Mortis The Rigidity of Death (Stiffness) • Without oxygen in the blood— • Calcium accumulates in the muscles • Muscles stiffen • Starts in the head and expands throughout • Begins after 2 hours • After about 15 hours— • Muscle fibers begin to dissolve • Softening begins • Ends after 36 to 48 hours

  12. Time of Death—Rigor Mortis

  13. Rigor Mortis • Factors that affect rigor • Temperature • Cooler is slower • Warmer is faster • Person’s weight – (body fat stores extra oxygen and will slow down rigor) • Obese – slows rigor • Thin – accelerates rigor • Type of clothing • Clothes accelerates rigor. • Naked body slows down rigor. • Illness – with fever, rigor will set in faster. • Hypothermia - the onset of rigor will be slower. • Physical activity - exercising, faster • Sun exposure – direct sunlight, faster • Sex – men have stronger rigidity • Age - Children tend to develop rigor sooner than adults • Asphyxiation and CO poisoning can delay onset

  14. Stages of Decomposition • A corpse decomposes in predictable ways in 5 stages. • Within 2 days after death: • Cell autolysis begins • Green and purplish color occurs • Skin takes marble appearance • Face becomes discolor • After 4 days: • Skin blisters • Abdomen swells • Within 6 to 10 days: • Corpse bloats • Chest and abdomen burst and collapse • Fluids leak • Eyeballs and other tissues liquefy • Skin sloughs off Decomposition = Rotting

  15. 1) Initial decay or Fresh Stage (0 to 3 days after death) Although the body shortly after death appears fresh from the outside, the bacteria that before death were feeding on the contents of the intestine begin to digest the intestine itself. They eventually break out of the intestine and start digesting the surrounding internal organs. The body's own digestive enzymes (normally in the intestine) also spread through the body, contributing to its decomposition.

  16. 1)Initial or Fresh Decay • At time of death • The heart stops • The skin gets tight and grey in color • Cell start to die (brain 3-7 min; skin up 24 hours) • All the muscles relax • The bladder and bowels empty • Nails do not grow

  17. After 24 hours • These are the changes: • Body temperature is equal to environmental • The head and neck are now a greenish-blue color that spreads over the whole body • There is the strong smell of rotting meat • The face of the person is essentially no longer recognizable

  18. Putrefaction or Bloated Stage4 to 10 days after death 2) Bloat Stage (4 to 10 days after death) The build up of gas resulting from the intense activity of the multiplying bacteria, creates pressure within the body. This pressure inflates the body and forces fluids out of cells and blood vessels and into the body cavity. The pig has become bloated from the build up of gases within the body.

  19. 2. Bloat • After about 4 days: • Gases in the body makes the skin blistered • The front of the body swells • Tongue may protrude • Fluid from the lungs oozes out of the mouth and nose • Terrible smell from the various gases (hydrogen sulphide and mercaptans)

  20. 3) Black putrefaction or (10 to 20 days after death) A large volume of body fluids drain from the body at this stage and seep into the surrounding soil. Other insects and mites feed on this material. The insects consume the bulk of the flesh and the body temperature increases with their activity. Bacterial decay is still very important, and bacteria will eventually consume the body if insects are excluded. The pig's body has collapsed with black exposed surfaces and creamy flesh.

  21. Putrefaction (decay) • The soft tissues rapidly disappear due to autolysis, bacterial, insect and other animal activity • The body collapses on itself as the skin is compromised and cannot hold the gases. • Adipocere (corpse wax) formed during the decay process under suitable conditions. • Result of acumulation of saturated fatty acids which lower the pH and inhibit microbial growth.

  22. 4) Butyric fermentation or Post Decay Stage (20 to 50 days) All the remaining flesh is removed over this period and the body dries out. It has a cheesy smell, caused by butyric acid, and this smell attracts a new suite of corpse organisms. The surface of the body that is in contact with the ground becomes covered with mould as the body ferments. The pig is now very flat and beginning to dry out.

  23. 5) Dry decay or Skeletal Stage (50-365 days after death) The body is now dry and decays very slowly. Eventually all the hair disappears leaving the bones only. The pig has been reduced to hair and bone.

  24. Putrid dry remains • The stage where the skin and soft tissues are no longer present (or in very limited amounts) • Bones, tendons, hair and fingernails remain • Still smell of decay • Bones also decay (diagenesis) • Chemical and structural (microscopic)

  25. Mummification • Decay in dry conditions, both warm and cold, with strong air current leading to increased water loss • In deserts, cold places • Murder victim placed in chimneys • Can be preserved for hundreds and thousands of years (provided there are no insects feedeing on them).

  26. Summary of Factors PROMOTING DECAY DELAYING DECAY

  27. Determining the time of death?

  28. Time of Death —Stomach and Intestinal Contents

  29. Time of Death: Stomach and Intestinal Contents

  30. Stomach and Intestinal Contents Based on these specifics, give an estimate for each of these on how much time has passed since the meal was eaten: • Food is still present in the stomach. • The stomach is empty but food is found in the small intestine. • The small intestine is empty but waste is present in the large intestine.

  31. Changes of the Eye • Surface of eye dries out. • Thin film observed within 2 to 3 hrs if eyes were open and within 24 hrs if eyes were covered after death. • Eyes become softer as a result of less fluid pressure behind the eye and the degree to which this has occurred can be used as a measure of the time since death. • Following death, potassium accumulates inside vitreous humor. • The buildup of potassium may be used to estimate the time of death.

  32. Eye Film Develops

  33. Petechial Hemorrhages Bleeding is a loss of blood from the body and hemorrhage means bleeding profusely. • This condition is called petechial (tiny dots) hemorrahage (bleeding). • Video Clip

  34. Time of Death—Stages of Decomposition Choose: A. Within 2 days.B. After 4 days.C. Within 6-10 days. • Fluids begin to leak from body openings as cell membranes rupture • Discoloration of the face • The skin sloughs off • The skin blisters • Green and purplish staining from blood decomposition • The corpse bloats • Eyeballs and other tissues liquefy • The abdomen swells • Marbling appearance on the skin C A C B A C C B A

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