Post-Mortem
Changes
Time of Death
Post-Mortem Changes
 Livor Mortis/ Hypostasis
 Rigor Mortis
 Algor Mortis/ Body Cooling
 Decomposition
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.
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
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.
Taché Noire
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).
Terminology
 Postmortem Lividity: Physiochemical changes of the
Body after Death
 Livor Mortis: Discoloration after Death
 Rigor Mortis: Stiffness after Death
 Algor Mortis: Body temperature after Death
 Putrefaction
 Decomposition and Autolysis
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
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
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.
Hypostasis/Livor Mortis
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.
Blanching
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.
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.
Livor Mortis
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
Lividity
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
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.
Lividity
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
Pink, cherry-red
Excessive oxygenated blood
because of inhibition of
cytochrome oxidase
Refrigeration/hypothermia
Pink, cherry-red
Oxygen retention in
cutaneous blood by cold air
Hydrogen sulfate
Green
Sulfhemoglobin
Sodium chlorate
Brown
Methemoglobin
Hypostasis vs. Bruises
(Ecchymosis)
Hypostasis
Dependant areas
Bruises
Any where
Well defined edges
Blood is retained in
intact capillaries
Superficial
Same level on surface
Pale over pressure
areas
Incision: blood flows
from the cut vessel
(washable)
No swelling
Ill defined edges
Blood escapes through
ruptured capillaries
Deep into skin
Raised
Red
Incision: blood
coagulates in tissue
May be with swelling
With a bruise, blood
will not flow from the cut
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.
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
Tardieu Spots
Tardieu Spots
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
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.
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
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
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
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
RM: time estimation
Warm
Flaccid
Death < 3 hrs
Warm
Stiff
3-8 hrs
Cold
Stiff
8-36 hrs
Cold
Flaccid
Death > 36 hrs
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
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
Cadaveric Spasm
Rigor Mortis vs. Cadaveric
Spasm
Rigor mortis
Cadaveric spasm
Onset delayed after death (2-3 hrs)
Duration approx 12-24 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 Mechanism of formation unknown, but
ATP below critical level
predisposing factors: Excitement, fear,
fatigue, exhaustion, nervous tension,
contraction of muscles at time of death
All muscles of the body are affected
Selected muscles, which were in a state
gradually.
of contraction at the time of death, are
affected.
Cadaveric spasm in a drowning victim:
had grass from the river bank firmly
clutched in the hand
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
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.
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
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.
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.
POST-MORTEM
DECOMPOSITION
Post-Mortem
Decomposition
1. Putrefaction
2. Mummification
3. Adipocere
4. Skeletonization
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.


3 - 4 days: staining spreads.


Body begins to swell.
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.
Marbling (Arborization)
Marbling
Marbling with Purging
Putrefaction

The normal final sign of death.

Starts immediately after death at the cellular level

Becomes visible in 48-72 hrs.

Its onset may be sped up or delayed by several factors mainly:



Temperature
Humidity
Two phenomena for putrefaction:


Autolysis: occurs by digestive enzymes released from the cells after
death.
Bacterial action: most of them come from the bowel and
Clostridium welchii predominates (same bacteria that causes gas
gangrene)

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.
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
Early decompositional changes are manifested
by green discoloration over the abdomen.
Putrefaction
 Middle Stage: 36-48 hours
 Gaseous bloating, green-purple color in face, neck
and shoulders.
Putrefaction
Putrefaction
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
Putrefaction
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).
Putrefaction
Putrefaction
Putrefaction
Skin Slippage
Fingerprinting Using
Finger From Deceased
Putrefaction
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.
Influences on Putrefaction
 Heavy clothing and other
coverings, by retaining body
heat, will speed up
putrefaction.
 Rapid putrefactive changes
may been 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.
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.
 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.