Text of Post-Mortem Changes Time of Death. Post-Mortem Changes Livor Mortis/ Hypostasis Rigor Mortis ...
Time of Death
Livor Mortis/ Hypostasis
Algor Mortis/ 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
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
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
discoloration appear at each side of the cornea, either brown or
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-
Absence of intraocular fluid suggests more than 4 days.
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
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.
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
Thumb pressure indicates that the lividity is not fully fixed.
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.
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
Postmortem Changes Postmortem changes are affected by:
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?
The lung is dark purple in the posterior dependent areas as a result of livor mortis. This may simulate congestion.
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.
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.
Marbling with Purging
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
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.
PutrefactionThree 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
Putrefaction Middle Stage: 36-48 hours
Gaseous bloating, green-purple color in face, neck and shoulders.
Bloat First sign that microbial proliferation is
Accumulation of gases in body cavities causes distention of the abdomen
Insects feed on the body’s tissues Post-mortem skin ruptures
Allows gases and fluids to escape = Purging
Putrefaction Late Stage: greater than 72
hoursBloatingPostmortem mucosal purge,
tongue swells and protrudes, venous marbling of subcutaneous vessels
Skin blebs or blisteringExplosion of this person can occur
PutrefactionLate Stage (Cont.): greater than 72
Skin and hair slippage skin of hands or feet can shed with nails
Marked bloating (1-3X)
Skeletonization (from 4-5 days and up to 1.5 years depending on the climate).
Fingerprinting Using Finger From Deceased
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
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
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
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.
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
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