Forensic taphonomy

Forensic taphonomy is the interdisciplinary study and interpretation of postmortem processes of human remains in the dispositional context, i.e., the history of changes of a body following death.

Knowledge of the signs of death help to differentiate death from suspended animation.

Types	Changes
Immediate changes (somatic)	Stoppage of nervous system Stoppage of circulatory system Stoppage of respiratory system
Early changes (Cellular death)	Pallor of skin  Loss of elasticity of the skin  Changes in eye Primary flaccidity of muscle  Cooling of body  Post mortem staining/lividity  Rigor mortis
Late changes (decomposition and decay)	Putrefaction  Mummification  Saponification (Adipocere formation)

Medicolegal Important of Late changes after death

1. Surest sign of death
2. Estimation of time of death

Changes in the Skin:

1. The skin becomes pale and ashy-white

2. Loss of elasticity

3. The lips appear dark-red to black, dry, and hard due to drying

4. Contact flattening

Changes in Muscle:

1. Primary flaccidity/relaxation

2. Rigor mortis

3. Secondary flaccidity/relaxation

Changes in the Eyes:

 

Post mortem caloricity

It is a condition in which, instead of cooling of the body, the body temperature remains raised for the first 2 hours or so after death.

 

Condition/Examples:

1. Post-mortem glycogenolysis

2. Infection's disease: septicemia or bacteremia, excessive bacterial activity, as in septicemia condition,  cholera and other fevers

3. Heatstroke

4. High atmospheric temperature

5. Increase in heat production in the muscles due to convulsion as  in case of Tetanus and strychnine poisoning

 

COOLING OF THE BODY (ALGOR MORTIS)

Heat is generated by residual metabolic process (glycogenolysis) of dying tissues and by the metabolic activity of intestinal bacteria, due to which body temperature does not fall for some time.

Internal organs cool primarily by conduction. Conductive heat exchange occurs due to the temperature difference between the body and surroundings. e.g. clothing, covering, air, water, etc. The body heat is mostly lost by conduction and convection.

At non-contact areas heat exchange occurs by convectional mechanism, which exceeds that of the contact surface.

For about half to one hour after death, the rectal temperature falls little or not at all. (postmortem temperature plateau). This is followed by a linear rate of cooling (between 0.4 to 0.6°C per hour) for the next 12 to 16 hours.

The temperature can also be recorded by making a small opening into the peritoneal cavity and inserting the thermometer in contact with the inferior surface of the Iiver.

A rough idea of approximate time in hours of death can be obtained by using the formula:

(Normal body temperature — rectal temperature)/Rate of temperature fall per hour

 

Variations in rectal temperature:

The rectal temperature is between 36.5 to 37.5°C. Rectal temperature is about 0.6°C higher than oral.

In cases of fat or air embolism, certain infections, septicemia, heatstroke and in pontine hemorrhage, thyrotoxicosis, psychotic (emotional) stress, administration of neuroleptic medication, CO poisoning, intoxication with heroin and cocaine, drug reactions, etc. a sharp rise in temperature occurs.

 

Factors affecting rate of cooling:

Atmospheric temperature: Greater the difference in temperature between the body and atmosphere, the more rapid in the rate of cooling.

In tropical climates, the heat loss is roughly 0.4°C to 0.6°C and in temperate countries 1°C per hour.

Media of disposal of the dead body: rate of cooling is high in water media, than air and than the grave. The ratio media is water: air: grave: 4:2:1

Body built: The rate of heat loss is proportional to the weight of the body to its surface area. Thus, children and old people cool more rapidly than adults. A thinly built dead body loses heat rapidly and vice versa.

Sex: female bodies retain body heat for a comparatively longer period (due to high subcutaneous fat)

Age: more heat loss in infants.

Clothing or coverings of the body: retain heat for longer period

Air movement: increase air movement- increase rate of cooling

Dry weather: promotes heat loss

Position and posture of the body: in a body with outstretched limbs, the loss of body heat is more.

Post mortem caloricity: it reduces the rate of cooling.

Time of death= (Normal body temperature-Rectal temperature) ÷ Rate of temperature fall per hour

 

Temperature measurement area in death body

1. Rectum (4 inches above)

2. Sub-hepatic area

3. External meatus & nostril

 

Medico-legal importance of cooling

Confirmatory sign of death

Time since death can be roughly estimated

Sometimes it indicates the cause of death

It indicates the place of exposure

 

Different types of stiffening/causes of stiffening:

Rigor Mortis/Cadaveric rigidity/Death stiffening

Cadaveric spasm/Instantaneous rigor

Heat stiffening (due to protein denaturation & coagulation)

Cold stiffening (freezing of the body fluids and solidification of subcutaneous fat simulating rigor.)

Gas stiffening

 

MUSCULAR CHANGES

After death, the muscles of the body pass through three stages:

(1) Primary relaxation or flaccidity.

(2) Rigor mortis or cadaveric rigidity.

(3) Secondary flaccidity.

 

Primary Flaccidity:

During this stage, death is only somatic (no cellular death) and it lasts for one to two hours. All the muscles of the body begin to relax soon after death. The lower jaw falls, eyelids loose tension, and joints are flexible.

Body flattens over areas which are in contact with the surface on which it rests (contact flattening).

Muscles are relaxed as long as the ATP content remains sufficiently high to permit the splitting of the actin-myosin cross-bridges.

Muscular irritability and response to mechanical or electrical stimuli persist.

Pupils react to atropine or physostigmine,  but not to light.

 

Rigor Mortis (Cadaveric rigidity/death stiffening)
Appears 1-2 hours after death

It is a state of stiffening of muscles, sometimes with slight shortening of the fibers. Individual cell death takes place in this stage.

 

The Order of Appearance of Rigor:

All muscles of the body, both voluntary and involuntary are affected.

It does not start in all muscles simultaneously (Nysten's rule).

It first appears in involuntary muscles; the myocardium becomes rigid in an hour.

It begins in the eyelids, neck, and lower jaw and passes upwards to the muscles of the face, and downwards to the muscles of the chest, upper limbs, abdomen, and lower limbs, and lastly to the fingers and toes. In individual limbs, it usually progresses from above downwards.

Eyelid - Neck

Lower jaw

Muscles of face

Muscles of the chest, upper limbs, abdomen, and lower limbs

Lastly to the fingers and toes

Development:

The development of rigor is concerned with muscles only. It is independent of the integrity of the nervous system, though it is said to develop more slowly in paralyzed limbs.

 

Diagnosis/Testing of Rigor Mortis

Rigor is tested by trying to lift the eyeLids, depressing the jaw, and gently bending the neck and various joints of the body. Note the degree (absent, minimal, moderate, advanced, or complete) and distribution.

1st internally appearance of rigor mortis Myocardium

1st externally appearance of rigor mortis Upper eyelid

The disappearance of Rigor mortis Onset after the putrefaction

 

 

Order of disappearance of Rigor Mortis

Which appears first, that disappear first. Same as the order sequence of appearance of rigor mortis

Eyelids, neck, and lower jaw

muscles of the face—muscles of the chest, upper limbs —abdomen and lower limbs —lastly in the fingers and toes.

 

Time of Onset:

In India, it begins one to two hours after death and takes a further one to two hours to develop.

 

Rule of 12:

0-12 hrs — Within this interval, rigor mortis develops, and peaks.

12-24 hrs — Within this interval, rigor mortis remain.

24-36 hrs — Within this interval, rigor mortis disappear progressively.

 

Mechanism

Normally, for the relaxation of a muscle after contraction, ATP is needed.

After death— no further synthesis of ATP which is necessary for relaxation— no separation of actin-myosin complex— causes hardening

 

During life, the separation of the actin and myosin filaments, and the energy needed for contraction are dependent on adenosinetriphosphate (ATP).

Three metabolic systems are responsible for maintaining a continuous supply of ATP in the muscle:

(1) Phosphagen system

(2) Glycogen-lactic acid system

(3) Aerobic system

The dephosphorylation of ATP by the action of ATPase produces ADP and phosphate, and a large amount of energy, which is used for muscle contraction.

The free phosphate then engages in a phosphorylation reaction that converts glycogen to lactic acid. The lost ATP is replaced during life by resynthesis, which is dependent upon the supply of glycogen.

The lactic acid enters the bloodstream and is reconverted to glycogen in the liver.

 

At the time of somatic death, enough ATP is present in the muscle to maintain relaxation. After death, the ATP is progressively and irreversibly destroyed leading to increased accumulation of lactates and phosphates in the muscles. There is no resynthesis of ATP.

Postmortem loss of integrity of the muscle cell sarcoplasmic reticulum allows calcium ions to flood the contractile units of the muscle fibers (sarcomeres) initiating the binding of actin and myosin molecules and mimicking the normal contraction process.

Normal relaxation in life is achieved by energy-dependent (ATP-driven) pumping of calcium back across the membrane of the sarcoplasmic reticulum, but this fails after death because of membrane disruption and lack of ATP, due to which increased calcium level in the sarcomeres causes muscle contraction.

When the ATP is reduced to a critical level (85% of the normal), the overlapping portions of myosin and actin filament causes hardness and rigidity of muscle rigor. 

The rigidity of the muscle is at its maximum when the level of ATP is reduced to 15%.

The actin-myosin complex is trapped in a state of contraction until it is physically disrupted by the onset of putrefaction.

 

 

Medico-legal importance of Rigor mortis

Sign of death

Helps in estimating the time of death

The position of the dead body at the time can be known from contact flattening.

Rigor mortis indicates the molecular death of the muscles involved.

Factors affecting/stimulating rigor mortis:

Age: does not develop in a fetus <7 months intra-uterine age. In healthy adults, it develops slowly but is well-marked and lasts longer, while in children and old people it is feeble and rapid.

Body built/physique of the subject: rigor mortis comes early and passes off early in thinly built subjects with weak musculature.

Atmospheric temperature: at high atmospheric temperature, rigor mortis comes early and passes off early. The onset is rapid due to heat, because of the increased breakdown of ATP, but the duration is short.

In death due to exhaustive disease, or when convulsive proceeds death, rigor mortis appears and passes off early.

In death due to wasting disease, rigor mortis comes early and passes off early.

It may disappear very rapidly in case of widespread bacterial infection, especially in gas gangrene, where putrefaction begins early. Rigor mortis is frequently absent in persons dying from septicemia.

 

Cadaveric spasm (instantaneous rigor/cataleptic rigidity)

It is a condition in which, the muscles that were contracted during life becomes stiff and rigid immediately after death without passing into the stage of primary relaxation.

The mechanism of cadaveric spasm is obscure but possibly may be neurogenic. Adrenocortical exhaustion which impairs resynthesis of ATP may be a possible cause.

As such, the change preserves the exact attitude of the person at the time of death for several hours afterwards.

No other condition simulates cadaveric spasm and it cannot be produced by any method after death. It passes without interruption into normal rigor mortis and disappears when rigor disappears.

 

Causes/Predisposing Factor

Sudden death

Intense physical and/or emotional activity such as excitement, fear, severe pain, exhaustion,

Cerebral hemorrhage, Injury to nervous system

Firearm wound of the head, Drowning

Convulsant poison e.g., strychnine

 

Medico-legal importance of cadaveric spasm

Occasionally, in case of suicide the weapon e.g., pistol of knife is seen in the victim's hand which is a strong evidence of suicide.

If the deceased dies due to assault, some part of clothing e.g., button of his assailant or some hair may be firmly grasped in the hands.

In case of drowning: grass, weeds or leaves may be found firmly grasped in the hands, which indicates that the victim was alive on entering the water.

 

Difference between rigor mortis and cadaveric spasm:

Traits	Rigor mortis	Cadaveric spasm
Onset	1-2 hours after death	Just after death (Instantaneous)
Muscle involves	All muscles (both voluntary & involuntary)	Usually a single group of voluntary muscle
Production	Freezing & exposure to temp.above 65C will produce rigor	Cannot be produced by any method after death
Death of muscle	Molecular death	No molecular death
Electric stimuli	Muscles do not respond	Muscle respond
Predisposing factor	No	Sudden death, excitement, fear, exhaustion, nervous tension,
Body temperature	cold	Warm
Muscle reaction	Acidic	Alkaline
Mechanism	ATP	unknown
Medico-legal importance	Indicates time of death	Indicates manner of death i.e suicide, homicide or accident

 

CONDITIONS SIMULATING RIGOR MORTIS

 

1.  Heat Stiffening:

When a body is exposed to temperatures above 65°C. a rigidity is produced, which is much more marked than that found in rigor mortis. It is seen in deaths from burning, high voltage electric shock and from falling into hot liquid. Heat causes stiffening of the muscles, because the tissue proteins are denatured and coagulated as in cooking. Coagulation of protein is seen in burns on microscopic examination

 

The stiffening remains until the muscles and ligaments soften from decomposition and the normal rigor mortis does not occur.

 

2. Cold Stiffening:

When a body is exposed to freezing temperatures before acid metabolites appear in the muscles, the tissues become frozen and stiff, due to freezing of the body fluids and solidification of subcutaneous fat simulating rigor.

If the body is placed in the warm atmosphere, the stiffness disappears and after a time, the normal rigor mortis occurs rapidly and passes off quickly.

 

3. CADAVERIC SPASM or Instantaneous Rigor:

Cadaveric spasm (cataleptic rigidity) is a rare condition. In this, the muscles that were contracted during life become stiff and rigid immediately after death without passing into the stage of primary relaxation. As such, the change preserves the exact attitude of the person at the time of death for several hours afterwards.

 

Secondary Relaxation:

Flaccidity following rigor mortis is caused by the action of the alkaline liquids produced by putrefaction. Another view is that rigidity disappears due to solution of myosin by excess of acid produced during rigor mortis. A third view is that enzymes are developed in dead muscle which dissolve myosin by a process of auto-digestion.

Hypostasis (Postmortem staining) Time: well-developed within 4 hrs & reaches maximum in 6-12 hrs

This is the bluish-purple or purplish-red (due to deoxyhemoglobin) discoloration, which appears under the skin in the most superficial layers of the dermis  of the dependent parts of the body after death, due to capillo-venous distention.

It is also called postmortem staining, subcutaneous hypostasis, livor mortis, cadaveric lividity, suggestions, vibices, and darkening of death.

 

Mechanism:

 It is caused by the stoppage of circulation, the stagnation of blood in blood vessels, and its tendency to sink by force of gravity.

The intensity of the color depends upon the amount o f reduced hemoglobin in the blood. In cases of large amount of reduced hemoglobin before death, the blood has deep purplish-red color.

 

Development:

Postmortem lividity begins shortly after death, but it may not be visible for about half to one hour after death in normal individuals.

It is usually well developed within four hours and reaches a maximum between 6 to 12 hours (primary lividity) and persists until putrefaction sets in.

 

The physical factors for fixation of post mortem staining are:

(l) Blood cannot pass out of the capillaries after formation of p.m. hypostasis.

(2) Rigor mortis obliterates the big vessels, and as such the blood cannot pass through these vessels to settle in venules and capillaries in a new area.

(3) After full development of rigor mortis, venules and capillaries are compressed and almost empty and cannot be easily distended by the resettling blood. Hypostasis becomes fixed when blood leaks into the surrounding soft tissues due to hemolysis and breakdown of blood vessels.

 

Hypostasis may be sparse or even absent in deaths where considerable blood loss of at least 65% of the circulating blood volume in adults and 45% in infants, occurs before death due to trauma. In severe anaemia lividity will be absent.

 

Internal Hypostasis:

Hypostasis also occurs in the dependent parts of internal organs. When a body is in supine position, hypostasis is seen in the posterior portions of the cerebrum and cerebellum, the dorsal portions of the lungs, posterior wall of the stomach, dorsal portions of the liver, kidneys, spleen, larynx, heart, and the lowermost coils of intestine in the pelvic cavity.

 

Medico-legal importance of hypostasis

It is a sign of death

Its extent helps in estimation of time since death (unreliable)

It indicates the posture of the body at the time of death.

It may indicate moving of the body to another position sometime after death.

Sometimes, the color may indicate the cause of death.

 

Different color markings in a dead body:

Putrefaction

It is a process of liquefaction of elements or compound due to action of fermentation process or due to autolysis.

Decomposition= putrefaction+autolysis

The disintegration of body tissues after death is known as decomposition. The terms decomposition and putrefaction are used as synonyms. Putrefaction usually follows the disappearance of rigor mortis.

Mechanism of putrefaction:

Action of micro-organism	After death— O2 tension of the tissue reduces--anaerobic micro-organisms(within the body and environment) grow— they break tissue protein, fat and carbohydrates and production of foul—smelling gases- putrefaction proceeds. (micro-organisms: clostridium welchii, E. coli, Staphylococcus, nonhemolytic streptococcus, diphtheroid and proteus are the important ones)
Autolysis	After death cell membrane ruptures— release of cytoplasmic enzymes — breakdown of tissue CHO, protein, fat and other substances- tissue degradation- putrefaction proceeds.

Mechanism:

Organisms enter the tissues shortly after death, mainly from the alimentary canal, and less often through the respiratory tract or through an external skin wound.

The fall in the oxygen concentration in the tissues and rise in hydrogen ion concentration after death favor bacterial growth and spread throughout the body. Because the protective agencies of the body are absent, the bacteria spread through the blood vessels using the proteins and carbohydrates of the blood as culture media.

Destruction is caused mainly by the action of bacterial enzymes, mostly anaerobic organisms derived from the intestines. The chief destructive bacterial agent is Cl. welchii, which causes marked hemolysis, liquefaction of postmortem clots and of fresh thrombi and emboli, disintegration of tissue and gas formation in blood vessels and tissue spaces.

Lecithinase(enzyme) produced by Cl. welchii is most important. This hydrolyses the lecithin which is present in all cell membranes including blood cells·, and is responsible for the postmortem hemolysis of blood.

The other organisms include Streptococci, Staphylococci, bacteroids, anaerobic lacbobacilli , diphtheroids, Bacillus proteus, B. coli., B. aerogenes capsulatus, etc.

Stage's putrefaction:

No.	Stages	Time
1.	Color change appears in	Summer: 12-18 hours; winter:1-2days
2.	Development of foul smelling	Summer: 12-18 hours; winter: 1-2 days
3.	Appearance of maggots	Larvae: 8-24 hours; pupae: 4-5days
4.	Colliquative putrefaction (Liquefaction of Tissue)	5-10 days

Maggots are produced in one to 2 days which have proteolytic enzymes that dissolve the tissue.

 

The marbling of Skin:

The superficial veins especially over the roots of the limb, thighs, sides of the abdomen, shoulders, chest and neck are stained greenish-brown or purplish-red depending on the total amount of sulphhaemoglobin formation within the affected vessels (linear branching pattern) due to the hemolysis of red cells, which stains the wall of the vessel and infiltrates into the tissue, giving a marbled appearance (red, then greenish pattern in skin resembling the branches of a tree)

Development of Foul-smelling Gases:

The chemical processes in this stage are those of reduction, the complicated proteins and carbohydrates being split into simpler compounds of amino acids, ammonia, CO, CO2, hydrogensulphide,phosphorated hydrogen, methane and mercaptans.

Names of Putrefactive Gases:

1. Hydrogen Sulphide (Important)

2. Ammonia

3. Methane

4. CO, CO2

6. Phosphorated hydrogen

 

As a general rule, the organs show putrefactive changes in the following order.

(l) Larynx and trachea (12-24hrs)

(2) Stomach, intestines, pancreas and spleen

(3) Liver, lungs.

(4) Brain.

(5) Heart.

(6) Kidneys, bladder.

(7) Prostate, uterus.

(8) Skin, muscle, tendon.

(9) Bones.

 

1st External sign of appearance of decomposition

Right Iliac fossa

(Skin over the caecum)

Why?

1. Contents of the bowel are more fluid and full of bacteria.

2. Caecum lies superficially near the skin

 

Greenish discoloration of the skin over the region of the caecum

Due to conversion of hemoglobin of blood into sulphmethaemoglobin by the hydrogen sulphide formed in the large intestine and escaping into the surrounding tissues. 

 

1st Internal appearance of decomposition

Aorta intima

Undersurface of liver

 

1st organ to decomposed

Larynx & trachea

Then stomach, intestines

Last organ to decomposed

Uterus (in female)

Prostate (in male)

 

How to differentiate sex in death body in decomposed body.

Finding of uterus or prostate, because these uterus & prostate are the last organ to decomposed

In advanced decomposed, if these organs cannot be found, then other examination.

 

Medicolegal importance of putrefaction

Time since death can be estimated from the stages of decomposition.

Advanced decomposition may obliterate the identity of the dead.

Advanced decomposition may also obliterate the cause of death.

 

How to diagnose decomposition?

Feature/cardinal signs/characteristics of putrefaction:

Changes in the color of tissues 

The evolution of the gases in the tissues.

The liquefaction of the tissues

Last change in decomposition is liquefaction.

 

Factor influence decomposition in water

Water temperature

Stagnancy of water— in stagnant water, decomposition is rapid than flowing water.

Quality of water— Decomposition is slow in fresh water

Aquatic animals — will favor the decomposition

 

Factors influencing floatation of dead body on water

Early Decomposition

Salty water more sp.gravity

Stagnant water

Clothing, Sex(Female)

 

Effects (Pressure) of Putrefaction

Difficulty in identification

Distention of body cavities & hallow organs

Discharge if forth fluid from mouth & nostrils.

Formation of post mortem blister due to accumulation of gas under epidermis

Gas stiffening

Explusion of food particles and feces through anus

If deceased was pregnant, post mortem delivery may occur

 

Difference between Ante-Mortem and Post mortem blister:

Traits	Ante-mortem	Post-mortem
Fluid	More	Less
Transparency of fluid	Clear	Reddish
Presence of albumin	Rich	Poor
Zone of inflammation	Red Ring present	Absent
Base of the floor	Velvety appearance	White and glistening

 

Mummification

It is a late post-mortem change in which there is rapid drying of the dead body due to some environmental factors, when the soft tissues become dark, hard and stay preserved. The dry, hard skin gets almost adhere with the underlying bones is known as mummification.

Rapid drying & shriveling of the dead body due to evaporation of water but the natural appearances of the body and general facial features are preserved.

 

Time: 3 months to 1 years 

 

Requirement for mummification

Dry weather

Hot atmosphere

Absence of moisture

Free of air movements

 

Influencing factors of Mummification

Hot atmosphere

Dry atmosphere

Free air movement

Contact of body with absorbing media

 

Medico- legal importance Mummification

It gives a rough idea about the time since death.

Identification: in this condition the body is not grossly destroyed and many identification features like old scars, deformities, tattoo marks etc. can be detected after a long time.

Cause of death: as the body is not grossly destroyed, injuries can be detected after a long time.

The place of disposal of the dead body after death can be guessed (dry hot place with absorbing type of soil, etc.)

 

Saponification (adipocere formation)

Formation of soft, whitish, crumbly, waxy and greasy materials occurring in fat/fat containing tissue of a dead body.

Adipocere (cire=wax) is a modification of putrefaction. In this, the fatty tissues of the body change into a substance known as adipocere. It is seen most commonly in bodies immersed in water or in damp, warm environment.

 

Mechanism of Saponification

Due to hydrolysis & hydrogenation of body fats. The process needs water, and at initial phase utilizes the body fluid..

The chemical reaction involves change of fat to higher fatty acid like palmitic acid, stearic acid.

 

Mechanism:

The change is due to the gradual hydrolysis and hydrogenation of pre-existing fats, such as olein, into higher fatty acids, which combine with calcium and ammonium ions to form insoluble soaps, which being acidic, inhibit putrefactive bacteria.

Ultimately, the whole of the fat is converted into palmitic, oleic, stearic and hydroxystearic acid, together with some glycerol, and a mixture of these substances forms adipocere.

The process starts under the influence of intrinsic lipases, and is continued by the bacterial enzymes of the clostridia group, mainly Cl. perfringens, as the bacteria produce lecithinase, which facilitates hydrolysis and hydrogenation . Water is essential for the bacterial and enzymatic processes involved in adipocere formation.

 

Factor influencing saponification

Atmospheric temp. Heat favor it

Moisture favor

Air movements inhibit the process

Running water inhibit it

Medico-legal importance of Saponification

1) When the process involves the face, the features are well preserved, which help to establish the identity.

(2) The cause of death can be determined, because injuries are recognized.

(3) The time since death can be estimated.

 

Maceration

Process of aseptic autolysis of dead fetus occur when the dead child remains in the uterus for about 3,4 days surrounded with liquor amine but the exclusion of air

 

Difference between putrefaction & maceration

	Putrefaction	Maceration
Mechanism	Action of microorganisms and autolysis	Aseptic autolysis
Site of occurrence	Out side of uterus	Inside the uterus
Role of air	Enhance the process	No role or inhibit it
Smell	Offensive foul smell	Sweetish
Color of skin	Green	Red or purple
Condition of viscera	Soft & flabby	Soft & edematous

CONDITIONS PRESERVING THE BODY

1. Embalming is the treatment of the dead body with antiseptics and preservatives to prevent putrefaction and preserve the body. By this process proteins are coagulated, tissues are fixed, organs are bleached and hardened and blood is converted into a brownish mass. Embalming produces a chemical stiffening similar to rigor mortis, and normal rigor does not develop. Embalming rigidity is permanent.

 

Formalin (Preservative)

 Sodium borate (Buffer)

Sodium citrate (Anticoagulant)

Glycerin (Wetting agent)

Sodium chloride (Controls pH)

Eosin (1%, Cosmetic)

Soluble wintergreen (Perfume)

Water (Vehicle)

 

2) Mummification.

(3) Adipocere formation.

(4) Freezing

 

Difference between post mortem staining and Bruise

	Post mortem staining	Bruise
Situation	On the dependent part of dead body	Anywhere
Tissue level	Under the skin	Subcutaneous level
Causes	Due to capillo-venous distention with blood	Due to extravasation of blood  from capillaries
Effect of pressure	Pressed spot appears pale	No change
Cut section	Cut surface show oozing of blood from smaller vessels which can be cleaned by washing	Cut surface shows evidence of hemorrhage in the tissue which cannot be washed out (in dead bodies)
Medico-legal imp	Tells about the time of death and position of dead body	Tells about the nature of injury, weapon, used, etc.

Difference between post mortem staining & congestion

	Post mortem staining	Congestion
Situation	Dependent part of organ	Whole part if organ, affected with pathology
Cut surface	Oozing of blood from distended capillaries	Exudation of fluid mixed with blood from cut surface
Cause	Passive capillovenous distension	Due to some pathology in organ
Nature	Post-mortem	Ante-mortem
Swelling	Nil	May present

Difference between Rigor Mortis &Heat stiffening

	Rigor Mortis	Heat stiffening
Mechanism of formation	Due to depletion of ATP in muscle	Due to heat coagulation of protein
Time	1-2hrs after death	May be ante-mortem or post-mortem Formed due to contact with heat
Role of heat	Atmospheric high temperature enhances the process	Temp above 65 C
External appearance	Nothing specific	Sign of exposure to heat will be there like burning, blister formation

Difference between Primary & Secondary Relaxation

	Primary relaxation	Secondary relaxation
Time	Immediately after death	After rigor mortis passes off & decomposition occurs
Death of muscle	Has not occurred	Molecular death has occurred
Respond to stimuli	Respond	Does not respond
Body temperature	Near normal	Low
Other external features	Not particular	Sign of decomposition present

- Estimation of time since death:

1. Cooling of the body: starts from ½ to 1 hour after death

2. Cadaveric hypostasis: starts from 1 hour after death and well-marked within 5-12 hours.

3. Rigor mortis: instantaneous with death

4. Adipocere formation

5. Mummification

6. Degree of digestion of stomach contents

7. Condition of bladder

8. C.S.F

9. Bone marrow

10. Blood3. Saponification (Adipocere formation)