Many types of changes to a body occur after death. Some of those that can be used to determine the post-mortem Interval are –
Change In The Eye
Stomach & Intestinal Contents
Contents Of Urinary Bladder
Bone Marrow Changes
Changes can also differentiate
in following stages:-
The changes which take is may be
helpful in estimation of the approximate time of death and the sign of death
appear in the following order :-
I. Immediate Changes
Of Blood Circulation
II. Early Changes
In The Eye
III. Late Changes
STAGES OF DECOMPOSITION OF BODY
These Stages Of Post-Mortem Changes
Stage 1 – Fresh Stage
Stage 2 – Bloated Stage
Stage 3 – Active Decay Stage
Stage 4 – Post Decay Stage
Stage 5 – Skeletonization
This stage starts from the moment of death to the first signs of bloating of the body. The first organism to arrive are the blowflies (Calliphoridae).
Cessation of circulation and loss of muscles tone after death allows
blood within vessels to settle under gravity, producing a pink or purple colour
in those areas of the body that are lowest or dependent.
Hypostasis was maximal / fully developed after about 12 hours.
Rigor mortis is a temperature dependent physiochemical
phenomenon that occurs in muscle cells following cessation of a supply of
Rigor mortis develops at the same time through out the
body, but it is detected more rapidly in small muscles such as around eyes and
Algor mortis (post mortem body
A Body Cools After Death According To Old Rule. Body Temperature Falls By
1.50F (210C) Per Hour. The Rate At Which A Body Cools
After Death Depends On The Following-
Mass Of The Body,
Surface Area Of The Body,
Body Temperature At The Time Of Death (370C Is Used As Expected Temperature),
Site Of Reading Of Post Mortem Body Temperature,
Posture Of The Body,
Clothing And Coverings,
Obesity (Fat Insulates),
Breakdown of the body continues
because of bacterial activity, or putrefaction and this is the easiest stage to
distinguish. Gases causing the corpse to bloat are generated through metabolism
of nutrients by anaerobic bacteria.
Initially the abdomen swells but
later the whole body becomes stretched like an air- balloon.
At this stage more and more
blowflies are attracted to the body, possibly in response to the smell of the
Active Decay Stage
This stage is recognizable by the
skin of the corpse breaking up and starting to discard from body. The removing of skin allows the decomposition
gases to escape and so the inflation of the body gradually subsides as
Decomposition / Putrefaction
Dead Bodies Are Eventually Breaking Down Into Their Constituents
Soft Tissues Degrade And Liquefy Over A Period Of Time, The Rate Of
Progress Of Which Is Temperature Dependent. The Warmer The Environment In Which
The Body Lies, The More Rapid Liquefaction Occurs.
Dead Bodies Degrade At Different Rates Depending Upon The Medium In Which
They Are Placed- Immersion In Water Slows The Process, While Burial Slows The
Rate Even More.
When a body lies in dry condition it may desiccate instead of putrefying,
a process called mummification.
Mummified are dry and leathery and often brown in color.
Mummification commonly occurs in warm and hot climates, such as desert.
In the later stages of decay, all
that remains of the body are skin, cartilages and bones with some remnant of
flesh including the intestines.
Any remaining body tissue can be
dried. The biggest indicator of this stage is an increase in presence of beetles
and a reduction in the dominance of the flies (Diptera) on the body.
The Loss Of Soft Tissues Results In Skeletalisation. At This Stage Of The
Body Is Only Hair And Bones.
It May Take Years For A Body To Become Skeletonized When Buried But Weeks
In Warm Climates Where The Body Has Been Exposed To Predation.
The Body Has Clearly Reached Its Final Stage Of Decomposition.
:: Note ::
In Water These Stages Still Same With An Additional Stage Which Is
Floating Decay Stage, Where The Body Rises To The Water Surface.
At this point, besides aquatic insects such as chironomid larvae and
invertebrates such as water snails, terrestrial insect species also colonize
Bodies exposed to action of water or buried in damp, moist soil are opt
to undergo certain changes in the course of which they become saponified and
the formation of a substance known as adipocere is the result.
If The Body Is In An Environment Which Combines A High Humidity With High
Temperatures, The Subcutaneous Body Fat Of The Face, Buttocks (Breasts In The
Female) And The Extremities Become Hydrolyzed. Fatty Acids Are Released. These
Form Food For Bacteria, Which Can Speed Up The Rate At Which Adipocere Is Made.
Investigating post-mortem interval for a period of at least 3 or more months may mean that there is a large assemblage of flies, beetles and other insects present on the body. These can be use for the calculation of PMI using another method. This method requires that first of all every specimen identified to their family. After that an attempt is made to relate this ‘snapshot’ of decomposition fauna to the succession of insects which routinely colonize a corpse at that site knowing which insects are present and which are absent locally in what season help the entomologist to estimate the PMI.
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Forensic is; Observe a Little More – Archana Singh