Post-Mortem Changes

1. Post-Mortem Changes Time of Death

2. Post-Mortem Changes • Livor Mortis/ Hypostasis • Rigor Mortis • AlgorMortis/ Body Cooling • Decomposition • Five general stages are used to describe the process of decomposition in vertebrate animals: Fresh, Bloat, Active and Advanced Decay, and Dry/Remains • The general stages of decomposition are coupled with two stages of chemical decomposition: autolysis and putrefaction

3. Fresh Stage • Begins immediately after death • Heart has stopped beating • Blood drains to dependent areas of body due to gravity • Creating a bluish-purple discoloration = livor mortis • Also known as lividity • Rigor Mortis occurs in this stage along with Algor Mortis • Autolysis starts due to cellular breakdown and changes in pH

4. Indications of Death • Indications of death: • Unconsciousness • Loss of all reflexes • No reaction to painful stimuli • Muscular flaccidity • Cessation of heart beat and respiratory movement • Eye signs: • Loss of corneal and light reflexes • Mid-dilated position of the pupils • Irregular size and shape of the pupils • Eyelids usually closed incompletely • Tache noire: where the sclera remains exposed, two triangles of discoloration appear at each side of the cornea, either brown or black.

5. Postmortem Ocular Changes • Immediate signs in eyes • Dilated or fixed pupils • Absence of corneal and light reflex • Marked decrease in intra-ocular pressure • Late signs in eyes • Cloudiness of cornea • Increase in potassium levels

6. Early Postmortem Ocular Changes • Eyes remain open • Thin film observed over cornea within minutes • Taché noire • Eyes closed upon death • Cloudiness within twenty-four hours • Absence of intraocular fluid suggests more than 4 days.

7. TachéNoire

8. Time Since Death Interval • What Time Did the Person Die? • Best estimate; offered with a reasonable degree of medical and scientific certainty. • Impossible to be 100% accurate. • UNLESS a witness (who doesn’t lie) is present at the time of death, it generally is an estimate of time (2-4 hour window is the usual).

9. Terminology • Postmortem Lividity: Physiochemical changes of the Body after Death • Livor Mortis: Discoloration after Death • Rigor Mortis: Stiffness after Death • AlgorMortis: Body temperature after Death

10. Time of Death • To Evaluate Time Since Death: • Livor Mortis • Rigor Mortis • Body Temperature • Stages of Decomposition • Potassium Concentration in Vitreous Humor • Stomach Contents • Insect Activity • Scene Markers • Or a witness who can verify time of death

11. What is the Forensic Significance of Hypostasis? • Hypostasis is another term for Livor Mortis • Helps in determining • Time of death • Position of the body after death • Cause of death from color

12. Hypostasis (Postmortem Lividity) • Livor mortis is the settling of blood. • When the heart stops, the blood stops circulating and gravity makes it settle. The areas where the blood has settled will turn pink to dark red to dark blue or purple. • Starts happening immediately and is visible within a couple of hours. At this point skin is pinkish/bluish and blotchy. • After five or six hours the blotches have joined up but the skin still goes white when pressed. • After ten to twelve hours the blue color remains even when pressed. • The lividity doesn't show where the body is in contact with something. Thus a body lying on its back will show lividity in the small of its back, its neck etc., but not parts of the body directly touching the ground. • This a very useful when determining if a body has been moved after death.

13. Hypostasis/Livor Mortis

14. Livor Mortis • Postmortem Lividity • Early stages can “Blanch” the skin • Can shift position(s) from 1-8 hours • 8-12 hours congeals in capillary beds • After 12 -24 hours the lividity is typically “fixed” • Can continue to move up to 3 days after death • Blanching • Thumb pressure indicates that the lividity is not fully fixed.

15. Blanching

16. Distribution of Hypostasis If the body remains vertical after death as in hanging cases, hypostasis will be most marked in the feet and to a lesser extent the hands.

17. Livor Mortis • Noticeable approximately 30 minutes to 2 hours after death. • Reddish purple coloration in dependent areas of the body. • Due to accumulation of blood secondary to gravity. • Dependent areas resting on a hard surface may appear pale in color.

18. Livor Mortis

19. Sites of Hypostasis Depends on the position of the body before death: • Supine: • shoulders, buttocks • heels pressing against surface gives white color (pale). • Vertical (hanging): • distally in legs & feet. • Drowning: • chest, upper chest, and upper limbs. • Face-down death: • as in epilepsy, drunken victims • whitening around nose & lips. • Hypostasis may also occur in viscera: • Heart: mistaken for MI • Lungs: mistaken for pneumonia • Intestine: mistaken for hemorrhagic infarction

20. Lividity

21. Postmortem Changes • Postmortem changes are affected by: • Victim’s Age • Victim’s Pre-morbid Health • Level of Activity at time of death • Type of drugs taken prior to death • Ingestion of drugs prior to death • Current Environmental conditions

22. Can you see hypostasis in the internal organs? • Yes • The lung is dark purple in the posterior dependent areas as a result of livor mortis. This may simulate congestion.

23. Lividity

24. Cause of Death Analyzed by Livor Mortis

25. Hypostasis vs. Bruises (Ecchymosis) With a bruise, blood will not flow from the cut

26. Hypostasis • In advanced stages, skin level capillaries can hemorrhage • This causes pinpoint breaks in the skin called “Tardieu Spots” or petechiae. • Can see petechiae on internal organs. • These are minute hemorrhages in the soft tissue. • Scars show no lividity • Purpura = patches of purplish discoloration due to rupture of small vessels.

27. Tardieu Spots • Tardieu spots are petechiae and purpuric hemorrhages that develop in areas of dependency secondary to the rupture of degenerating vessels under the influence of increased pressure from gravity

28. Tardieu Spots

29. Tardieu Spots

30. Postmortem Rigor Mortis • Rigor Mortis • Chemical changes causes muscle mass to become rigid; looks like body is frozen in place (fixed) • Small muscles go into rigor first • Rigor usually occurs from head to toe • Rigor = Rigid • Mortis = Death

31. Rigor Mortis Formation • Mechanisms Leading to Rigor: • Metabolic activity after death continues for short time and becomes anaerobic (lacking oxygen) • ATP hydrolyzes to ADP • Calcium ions diffuse from sarcoplasmic reticulum • Causes chemical lock between actin and myosin proteins, THEN • As body proteins decompose, chemical locks breakdown and muscles become flaccid again.

32. Time table for Rigor Mortis • Rigor can be seen within 30 min. to 1 hour after death. • Covers the entire body after 8-12 hours. • Complete Rigor will remain for about 8-12 hrs. • Rigor begins to dissipate over the next 12 hrs. • This is dependent on environmental temperatures • Fully flaccid body by 36 hours. • Cadaveric Spasm • Drowning • Great Excitement prior to death

33. Rigor Mortis • Rigor is accelerated by • Prior exercise • Convulsions • Electrocution • Hyperpyrexia • Hot environmental temperatures • Age (does not form well in children) • Strychnine poisoning • Rigor is inhibited by • Hypothermia • Cold environment

34. Factors affecting timing of RM • Environmental temperature: • Cold and wet  onset slow, duration longer • Hot and dry  onset fast, duration shorter • Muscular activity before death: • Muscles healthy and robust, at rest before death  slow onset, duration longer • Muscles exhausted/ fatigued  onset rapid, esp in those limbs being used (eg in someone running at time of death, lower limbs develop RM faster than upper limbs) • Increase activity (convulsions, electrocution, lightning)  rapid onset & short duration

35. Factors affecting timing of RM • Age: • Extremes of age  rapid onset • Health: • Cause of death: • Asphyxia, pneumonia, nervous de’s with muscle paralysis & dehydration  slow onset • Septicemia & poisoning  rapid onset, may even be absent, especially in limbs affected by septicemia • Emaciated or died of wasting disease  rapid onset, short duration

36. RM: time estimation

37. What is the Forensic Significance of Rigor Mortis? • Can tell Time of Death • Can tell whether the body has been moved • May be able to tell cause of death

38. Cadaveric Spasm • Known as instantaneous rigor, cataleptic rigidity, or instantaneous rigidity • Rare form of muscular stiffening that occurs at the moment of death, persists into the period of rigor mortisand can be mistaken for rigor mortis • The cause is unknown, but usually associated with violent deaths happening with intense emotion • Occurs in deaths • Of Drowning • That occur with great excitement of tension

39. Cadaveric Spasm

40. Rigor Mortis vs. Cadaveric Spasm

41. Cadaveric spasm in a drowning victim: had grass from the river bank firmly clutched in the hand

42. What is the Forensic Significance of Cadaveric Spasm? • Diagnosis of suicide as in case of weapon found in hand • Drowning Diagnosis • ID of assailant as in case of evidence in hand • May allow one to know state of person prior to death • Stress • Exercise

43. Algor Mortis • Algor Mortis (Body Cooling) • Body cools from normal internal temperature to the temperature in the environment. • Liver or brain temperatures are taken for core temperature • Body cooling is inaccurate in obtaining time of death. • In 70 – 75°F, the body cools 2.5°F to 2.0°F for first hour, then 1.5 to 2.0°F for next twelve hours, then 1.0°F for next 12 hours. • Time since death = 98.6°F – Rectal Temp (°F)/ 1.5 • The rectum should be checked before insertion of the thermometer (May have been a sexual assault) • Patient may not die immediately after assault. • This may change time of death by several hours.

44. Algor Mortis • Under average conditions the body cools 2.0°F to 2.5°F per hour during the first hours and slower thereafter with an average loss of 1.5°F to 2°F during the first 12 hours and 1F for the next twelve to eighteen hours. • Measure inner core temperature • Liver or brain

45. Factors affecting Rate of Cooling • Body weight: • Larger bw: slower cooling • Smaller bw: faster cooling • Edema: • slower cooling rate. • Surface area of the body: • Larger surface area  speeds up cooling rate. • Children: increase surface area gives rapid heat loss.

46. Factors affecting Rate of Cooling • Clothing, posture and emaciation • Environmental Temperature: • Higher humidity: rapid cooling rate • Rapid air velocity: rapid cooling rate • Water: • Rapid cooling rate: • More rapid in flowing water than still water • If there is a fulminating infection, e.g. septicemia, the body temperature may continue to rise for some hours after death.

47. POST-MORTEM DECOMPOSITION

48. Post-Mortem Decomposition Putrefaction Mummification Adipocere Skeletonization

49. Decomposition • The decomposition of a body can be divided into several stages, even if the duration of each stage will vary a lot: • 2 - 3 days: green staining begins on the right side of the abdomen. • Body begins to swell. • 3 - 4 days: staining spreads. • Veins go "marbled" - a browny black discoloration • 5-6 days: abdomen swells with gas. • Skin blisters • 2 weeks: abdomen very tight and swollen. • 3 weeks: tissue softens. Organs and cavities bursting. Nails fall off • 4 weeks: soft tissues begin to liquefy. Face becoming unrecognizable • 4 - 6 months: formation of adipocere, if in damp place. • This is when the fat goes all hard and waxy. • A body without a coffin will be decayed within 12 years.

50. Marbling (Arborization)