1. Post-Mortem Changes
Time of Death

3. 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).

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. Taché Noire

8. Terminology
Following death many physiochemical changes occur to the body
Algor Mortis: Body temperature after Death
Livor Mortis: Discoloration after Death
Rigor Mortis: Stiffness after Death
Decomposition
Putrefaction and Autolysis

9. 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

10. Algor Mortis Algor Mortis (Body Cooling)
Body cools from normal internal temperature to the temperature in the environment (ambient temperature).
Liver or brain temperatures are taken for core temperature
Body cooling is inaccurate in obtaining time of death.

11. Algor Mortis Measure inner core temperature Liver or brain
At 70°F – 75°F, the body cools 2.5°F to 2.0°F for first hour, then 1.5°F 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.
Measure inner core temperature
Liver or brain

12. 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 have an increased surface area which allows for rapid heat loss.
Fat decreases the rate of heat loss and therefore, decreases the rate of cooling.

13. Factors affecting Rate of Cooling
Clothing 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.
Active air currents increase heat loss by convection – transfer of heat through moving air currents adjacent to the body

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

15. Livor Mortis
Purplish-blue discoloration due to the settling of blood by gravitational forces within dilated, toneless capillaries of the skin
Livor is seen in the dependent areas
On the back if the body was in a supine position or on the face and front if the body remained prone
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.
The areas where the blood has settled will turn pink to dark red to dark blue or purple.

16. Livor Mortis
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.
Within the areas of livor, pale areas where the skin was pressed against a hard surface or object will prevent postmortem sedimentation

17. Hypostasis/Livor Mortis

18. Blanching

19. Livor Mortis

20. 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 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.

21. Blanching

22. 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.

23. Livor Mortis

24. 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
Livor Mortis may not be visible is dark skin individuals. At autopsy, finding congestion of internal organs, such as the kidneys may assist in determining the presence of lividity.

25. Lividity

26. 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.

27. Lividity

28. 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

29. Cause of Death Analyzed by Livor Mortis
Etiology
Color of Liver
Mechanism
Normal
Red-Blue-Purple
Venous Blood
Carbon Monoxide
Pink, cherry-red
Carboxyhemoglobin
Cyanide
Excessive oxygenated blood because of inhibition of cytochrome oxidase
Refrigeration/hypothermia
Oxygen retention in cutaneous blood by cold air
Hydrogen sulfate
Green
Sulfhemoglobin
Sodium chlorate
Brown
Methemoglobin

30. Hypostasis vs. Bruises (Ecchymosis)
Dependant areas
Any where
Well defined edges
Ill defined edges
Blood is retained in intact capillaries
Blood escapes through ruptured capillaries
Superficial
Deep into skin
Same level on surface
Raised
Pale over pressure areas
Red
Incision: blood flows from the cut vessel (washable)
Incision: blood coagulates in tissue
No swelling
May be with swelling
With a bruise, blood will not flow from the cut

31. 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.
Scars are devoid of blood vessels and postmortem lividity does not affect scarred areas

32. 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

33. Tardieu Spots

34. Tardieu Spots

35. Rigor Mortis = Stiffness After Death
After death muscles are initially flaccid and can be moved easily
The flaccidity is followed by increasing stiffness or rigidity of the muscles
Joints are frozen
The rigidity will gradual subside and the body will be flaccid again

36. Postmortem 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

37. 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.
Death cessation of respiration depletion of oxygen used in the making of ATP ATP no longer provided to operate the SERCA pumps in the membrane of the sarcoplasmic reticulum, which pump calcium ions into the terminal cisternae Calcium ions diffuse from the terminal cisternae and extracellular fluid to the sarcomere  Ca binds with troponin  crossbridging between myosin and actin proteins.
Unlike normal muscle contractions, the body is unable to complete the cycle and release the coupling between the myosin and actin, creating a perpetual state of muscular contraction, until the breakdown of muscle tissue by digestive enzymes during decomposition.
RM initiated when the ATP concentration falls to 85% of normal

38. 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

39. Rigor Mortis Rigor is accelerated by Rigor is inhibited 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

40. 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

41. 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

42. RM: time estimation Warm Flaccid Death < 3 hrs Stiff 3-8 hrs Cold

43. 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

44. 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 mortis and 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

45. Cadaveric Spasm

46. Rigor Mortis vs. Cadaveric Spasm
Onset delayed after death (2-3 hrs)
Duration approx hrs
Onset is instantaneous
Duration is a few hours, until it is replaced by rigor mortis
Intensity comparatively moderate
Intensity comparatively very strong
Mechanism of formation: breakdown of ATP below critical level
Mechanism of formation unknown, but predisposing factors: Excitement, fear, fatigue, exhaustion, nervous tension, contraction of muscles at time of death
All muscles of the body are affected gradually.
Selected muscles, which were in a state of contraction at the time of death, are affected.

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

48. 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

49. POST-MORTEM DECOMPOSITION

50. Postmortem Decomposition
The disintegration of body tissues after death
Tissue components leak and release hydrolytic enzymes
Bacteria and other microorganisms thrive on the organic material of the body
Two parallel process of decomposition occur:
Autolysis: Self-dissolution by body enzymes released from disintegrating cells
Putrefaction: Decomposition changes produced by the action of bacteria and microorganisms

51. Putrefaction The normal final sign of death.
Starts immediately after death at the cellular level
Becomes visible in hrs.
Its onset may be sped up or delayed by several factors mainly:
Temperature
The ambient temperature can speed up or slow down this process
A fever prior to death can speed up putrefaction
Humidity
One week in air equals two weeks in water and eight weeks in soil

52. The 1st visible sign of putrefaction is green or greenish red discoloration of the skin of the anterior abdominal wall
Normally starts in the right iliac fossa.
The Next phase:
Gas formation
Blisters containing red fluid appear on the skin, mistaken as bleeding
Humidity, temperature, bacterial activity  body proteins break into
polypeptides & amino acids
Brain & Epithelial tissues are the 1st to be affected by putrefaction
Heart, Uterus & Prostate may survive for longer periods.
Military Plaques: nodules in heart (epi/endocardial)
Marbling: bacteria colonize venous system  hemolysis  stain.

53. The decomposition of a body can be divided into several stages, even if the duration of each stage may 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 brownish 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.

54. Marbling (Arborization)

55. Marbling

56. Marbling with Purging

57. Putrefaction Three Stages of Body Breakdown Early Stage: 24-36 hours
Green-like discoloration, usually in abdomen (R- low) due to denaturation of bacteria in the colon

58. Early decompositional changes are manifested by green discoloration over the abdomen.

59. Putrefaction Middle Stage: 36-48 hours
Gaseous bloating, green-purple color in face, neck and shoulders.

61. Putrefaction

62. Putrefaction

63. Putrefaction Late Stage: greater than 72 hours Bloating
Postmortem mucosal purge, tongue swells and protrudes, venous marbling of subcutaneous vessels
Skin blebs or blistering
Explosion of this person can occur

64. Putrefaction

65. Putrefaction Late Stage (Cont.): greater than 72 hours
Skin and hair slippage
skin of hands or feet can shed with nails intact
Marked bloating (1-3X)
Skeletonization (from 4-5 days and up to 1.5 years depending on the climate).

66. Putrefaction

67. Putrefaction

68. Skin Slipage

69. Skin Slippage

70. Fingerprinting Using Finger From Deceased

71. Hair Slippage

72. Active Decay Greatest period of mass loss
Voracious feeding of maggots
Purging of decomposition fluids
Liquefaction of tissue and disintegration
This stage ends when maggots migrate from the body to pupate

73. Advanced Decay

74. Influences on Putrefaction
A high environmental humidity will enhance putrefaction.
The rate of putrefaction is influenced by the bodily habits of the
decedent; obese individuals putrefy more rapidly than those who are
lean.
Putrefaction will be delayed in deaths from
exsanguination (bleeding to death) because blood provides a channel
for the spread of putrefactive organisms within the body.
Conversely, putrefaction is more rapid in persons dying with
widespread infection, congestive cardiac failure or retention of sodium
and salts.
It tends to be more rapid in children than in adults, but the onset is
relatively slow in unfed new-born infants because of the lack of
commensal bacteria.

75. Influences on Putrefaction
Heavy clothing and other coverings, by retaining body heat, will speed up putrefaction.
Rapid putrefactive changes may be seen in corpses left in a room which is well heated, or in a bed with an electric blanket.
Injuries to the body surface promote putrefaction by providing portals of entry for bacteria and the associated blood provides an excellent medium for bacterial growth.

76. Timeline of Putrefaction
2–3 days: Discoloration appears on the skin of the abdomen. The abdomen begins to swell due to gas formation.
3–4 days: The discoloration spreads and discolored veins become visible.
5–6 days: The abdomen swells noticeably and the skin blisters.
2 weeks: The abdomen is bloated; internal gas pressure nears maximum capacity.
3 weeks: Tissues have softened. Organs and cavities are bursting. The nails fall off.
4 weeks: Soft tissues begin to liquefy and the face becomes unrecognizable.
The exact rate of putrefaction is dependent upon many factors such as weather, exposure and location

77. Case Study
A 74-year old white male adult was found dead in his one room apartment.
When police arrived they found him face down sprawled across his bed.
The room was approximately 75°F.
There were no apparent injuries to this individual.

81. Your Thoughts
Police concluded the death was natural and did not called the Coroner’s office.
Do you agree with their conclusion?
Why or why not?
Write down your answer and give a full explanation why you think the police were either correct or wrong.
Make sure to use terminology presented in this power point presentation.