Death and its Forensic aspects

Introduction

Death is inevitable. Death is mourned upon since ages and have gathered attention of many philosophers, saints and scholars. Various definition of death were given by multiple experts and with evolution the definition has also evolved over time.
It came from a Greek word, ‘Thanatos’=death, and ‘logus’=science.
Thanatology=branch of medical science that deals with study of death.
In ancient times, Physician’s definition of death: ‘Sudden stoppage of circulation of blood with consequent cessation of vital functions’.
Black’s law dictionary (1968 edition): ‘the cessation of life, the ceasing to exist, defined by the physicians as total stoppage of circulation of blood and cessation of animal and vital functions consequent thereupon such as respiration, pulsation etc’.
Shapiro (1969): ‘the irreversible loss of the properties of living matter’.
Rentoul and smith (1973): ‘complete and persistent cessation of respiration and circulation
Over time, these definitions were challenged because they emphasized only on circulation and respiration.
They were also challenged by 2 recent medical advancement:
1. CPR (advanced resuscitation techniques)
2. Ventilators (advanced life sustaining equipment)
Due to these advancements new definition was required
‘Death is permanent and irreversible cessation of functions of three interlinked vital systems of the body namely, nervous, circulatory and respiratory system’. the ‘Tripod of life’
These are called as ‘atria mortis’ death’s portal of entry
This definition is also considered incomplete because:
1. Do not talk about brain death
2. Do not recognize the medical advancements
A model definition was formed by American Bar Association and National conference of commissioners of Uniform state laws:
“An individual who has sustained either (1) Irreversible cessation of circulatory and respiratory functions or (2) irreversible cessation of all functions of the entire brain including the brainstem, is Dead”.
Features of model definition
1. Complete and elaborative
2. Recognizes brain death and cardiorespiratory arrest
3. Acknowledges life sustaining aid and equipment

Statutory definitions:

I.Section 46 (IPC): “Death denotes the death of a human being unless the contrary appears from the context”

II.Section 2(b) of registration of Births and Death act 1969: “Permanent disappearance of all evidence of life at any time after live birth has taken place”

Medicolegal importance of death

Death declaration
Certification of death
Disposal of the body
Organ transplantation
Presumption of death

Types of death

Generally, there are 2 types of death as mentioned in studied in forensic medicine:

Somatic
Cellular death/molecular death

Somatic death:

Also called as clinical death or systemic death.
It is permanent and irreversible cessation of so called tripod of life i.e. Nervous system, cardiovascular system and respiratory system.
Individual cells may not die and respond to certain stimuli.
Somatic death means demise of the person
Doctors (RMPs) are entitled to issue a death certificate in case of somatic death

Molecular death:

It is also called as cellular death
Cells and tissues start to die in absence of circulation.
Certain tissues live up to certain time period and then die
WBCs live up to 12 hours after somatic death
Muscle cells die within 2 hours of somatic death
The brain cells die faster
Tissue needing more circulation dies faster.

The time between somatic death and molecular death is important for

Disposal of the body
Transplantation purpose

Brain death

There are three types of brain death

Cortical brain death
Brainstem death
Mixed or whole brain death

Cortical Brain Death

Also called cerebral brain death or persistent vegetative state.
All the cerebral functions are lost with severe brain dysfunction

Caused due to:

Hypoxic insult
Trauma
Toxic insult

The brain stem is intact
Respiration and circulation are sustained.
Such cases are not considered dead and are called living cadavers.
Disconnection of life support is permissible but is difficult in some cases

Brain stem death

It is considered death of the person
Respiration, circulation and ascending reticular pathways are arrested permanently.
The cerebrum may be intact but cut off from the brain stem.
Transplantation of Human organs act 1994:

“Brainstem death means the stage at which all the functions of the brainstem have permanently and irreversibly ceased and is so certified”

Whole brain death

Also called mixed brain death
Combination of cortical brain death and brain stem death
The brain cells die due to anoxia
The cerebrum dies first and then the midbrain and brainstem.

Determination of Brain death

Medicolegal aspects:

Organ transplantation
Discontinuation of life support
Determination of time of death for criminal and civil litigations.

Determination of brain stem death

Determination is done under Transplantation of Human Organs Act 1994 certified by board of experts.

The board has following members:

Registered medical Practioner in-charge of the hospital
An independent RMP nominated by in charge RMP from names approved
A neurologist or a neuro-surgeon nominated by RMP from the panel approved
The RMP treating the person

Diagnosing Criteria

Patient must be in deep coma, ‘Irreversible structural brainstem damage’
Exclusion of other causes of coma
Demonstrating absence of brainstem reflexes
No spontaneous respiration
Must be examined by the board of experts twice at an interval of 6 hours
Brain dead certificate has to be signed by all the members.

Other causes of coma

Hypothermia (temp below 32.2 degree Celsius)
CNS Depressants drugs like barbiturates, benzodiazepines etc
Metabolic and endocrine disturbances
Intoxication

Role of Brainstem reflexes in diagnosing brainstem death

Absence of following reflexes aids in declaration of brainstem death:

Absence of pupillary response
Absence of corneal reflex
Absence of vestibulo-ocular reflex (caloric response)
Absence of grimace
Absence of cough/gag
Absence of cranial motor nerve response to pain stimuli
Absence of spontaneous respiration.

Sudden death

“When a person of normal health dies, within 24 hours of onset of symptoms and signs of terminal illness, it is called sudden death”.

It may or may not be preceded by morbid symptoms
From medicolegal point of view, it may arise suspicion of foul play.
Certification of death is not possible just by external examination of the patient.
If the doctor has not attended the patient within two weeks, it is advisable not to issue a death certificate.

Causes of sudden Natural death

Cardiovascular: CAD, PDA, ASD, VSD, Aneurysms
Respiratory: BA, Viral Pneumonia, Obstruction, thrombo-embolism
CNS: Intra-cranial hemorrhage, cerebral thrombosis, embolism, tumor
Abdominal: perforated ulcer, hepatic failure, hemorrhagic pancreatitis
Endocrinal: adrenal hemorrhage, diabetic come, Sheehan’s syndrome
Iatrogenic: abuse of drugs, sudden withdrawal of Beta blockers
Miscellaneous: anaphylaxis, malaria, sickle cell crisis
Special causes in children: COT or SID
Indeterminate: in decomposed bodies.

CAD: Coronary Artery Disease

PDA: Patent Ductus Arteriosus

ASD: Atrial Septal defect

VSD: Ventricular Septal Defect

BA: Bronchial Asthma

SID: Sudden Infant Death

Signs of Death

Signs are the changes in the body following death and can be divided into three phases:

Immediate signs
Early signs
Late signs

Immediate signs

These are the signs in the body that happens immediately after death

It Includes:

Insensibility and loss of EEG rhythm (cessation of nervous system)
Cessation of circulation
Cessation of respiration

Cessation of nervous system:

Loss of sensation to touch pain and temperature
Loss of voluntary movements
Loss of reflexes and the muscles become flaccid
The pupils are dilated and fixed
These with loss of EEG rhythm for a continuous period of 5 minutes.
Signs of brain death as discussed earlier.

Cessation of circulation:

On palpation the pulsation are absent (radial, brachial, femoral and carotid)
Absence of heart sounds for continuously 5 minutes
Auscultation done at the apex of heart in the left fifth intercostal space
Auscultation is done a few times at short intervals.
Absence of ECG for continuously 5 minutes.

There are certain tests to assess circulation:

Diaphanous test
Magnus test
Icard’s test: 20% Alkaline dye fluorescence solution injected into dermis or subcutaneous tissue
Pressure test

Cessation of respiration:

No visible respiratory movements will be observed
No respiratory movements will be felt.
The breath sounds are absent when auscultation is performed
The absence of breath sounds continuously for 5 minutes is evidence of death

Tests to assess the Respiratory signs of death

Feather test: In this test a feather is brought near the nostrils of the dead. The feather won’t move in case of death. But when there is ongoing respiration, the movement in the feather can be easily seen.
Mirror test: A mirror is brought in close contact with nostrils of the body. If there are signs of breathing, vapors are formed on the surface of the mirror and if there is no respiration, no signs of vapor will be seen.
Winslow’s test: A bowl of water is kept on the chest. If there are waves on the surface of the water, it shows signs of respiratory movements. There will be no movements on water in case of death.

Early signs

The early signs of death can be studied under the following heads:

Changes in the eyes
Changes in the skin
Cooling of the body

Changes in the eye:

The lustre in the eye is lost due to absence of lacrimation
Reflexes are lost (pupillary reflexes), pupils becomes dilated and fixed
Muscle tone is lost (eye ball becomes flaccid)
Corneal changes: becomes partially hazy and completely hazy after 12 hours
Drying and desiccation of cornea happens
Cornea becomes wrinkled with central depression
Changes of Tache norie sclerotiques: blackish brown discoloration of sclera and conjunctiva
Initially it becomes yellowish (2-3 hours) and then converts to blackish brown discoloration (2-3 days). Happens when eyes remained opened.
Loss of ocular tension: normal pressure is 16-23 mmHg. Eyes become sunken
Pupils are circular but the shape may change due to loss of tone in ciliary muscles.
Retinal changes: due to arrest of circulation the retinal vessels becomes dotted and gives appearance of, ‘Cattle trucking’
Biochemical changes in the eyes:
- The linear rise in Vitreous potassium levels
- The vitreous Transaminase also rises steadily in the vitreous fluid.

Changes in the skin:

The skin becomes pale and gives ashy white appearance due to absence of circulation (more prominent in fair skin people)
Looses its elasticity and skin creases
Contact flattening is noted with pallor appearance
Cutis anserina may be observed

Cooling of the body:

Also known as ‘Algor Mortis’
Algor=coldness, Mortis=After death

The fall in the body temperature is due to:

There is no heat production due to loss of metabolic, physical and chemical Activity
The heat regulatory centres are stopped=constant heat loss till it coincide with environmental temperature.

Heat loss happens from the body by 3 mechanisms

Conduction
Convection
Radiation

Newton’s law and explanation

“Loss of heat from a body is directly proportional to the difference between the surface of the body and the surrounding at a given time”

It applies to inert body but not cadavers
Cadavers are composed of bone, fat, muscles, fluids protein etc.
Thus, the rate of fall of temperature is different in different body parts.
The surface cools first and then the core body temperature.
This due to insulation of skin and fat and other tissues.

If we take a curve:

Inert body gives an exponential curve
Cadaver gives sigmoid curve with initial phase of plateau
Initial 3-4 hours = loss of temperature from the surface (plateau)
For 9-12 hours = loss of core body temperature
After 16-20 hours, the body reaches the ambient temperature.

Recording of the body temperature:

Special chemical thermometer is used, “Thanatometer”
It is 25 cm long with graduation from 0 degree to 50 degree Celsius
Rectal temperature is taken from 4 inches depth
Or can also be taken from the Subhepatic region

Practical application:

The loss of body temperature is much faster in cold or temperate countries
In tropical countries like India, fall of temperature is slower
Due to increase in environmental temperature greater than the body temp
In India the average rate of cooling of body is 0.4 degree C to 0.7 C or 0.5 to 0.7 degree C per hour
General formula: time since death=normal body temperature(37.2)-rectal temperature, divided by avg rate of fall of temperature per hour (0.6)

Factors affecting cooling of the body

Atmosphere: The temperature will come down rapidly in cold climatic conditions and vice versa
Media of disposal: ratio of cooling in water, air and grave is 4:2:1 (Casper’s Dictum)
Body built: Bodies with more fat stores looses heat more slowly
Age: Children often looses heat more rapidly due to more surface area of their body corresponding to their size.
Clothing: Clothing do hampers the process of heat loss. More clothes, less heat loss
Air movement: Air movement speeds up the process of heat loss
Position and posture of the body
Cause of death: death due to septicemia etc is warm even after death

Post-mortem caloricity

Rise in body temperature in contrast to cooling of the body in dead.
Observed for first 2 hours

Causes:

Post-mortem glycogenolysis:

It is a compulsory phenomenon that happens after death.
In an average adult, post-mortem glycogenolysis produces 140 calories
Rise in body temperature may be 3.6 degree F or 2 degree Celsius.

Cause of death:

Infective conditions like bacteraemia, septicaemia
Sunstroke or pontine hemorrhage (loss of heat regulatory centers)
Tetanus poisoning due to rise in muscular activity.

Medicolegal importance:

It is a sign of death
Time since death can be calculated
Early cooling delays rigor mortis and retards decomposition

Post mortem Lividity

Also known as Livor mortis, post-mortem Hypostasis, Vibices, Suggilation, post-mortem staining.
Definition: “Post-mortem lividity is a purplish blue or reddish blue discoloration due to settling of blood by the gravitational force within the dependent, dilated and toneless small veins and capillaries of rete mucosum”

Formation and spread of Livor Mortis

After death, there is cessation of circulation
Blood remains in the blood vessels and capillaries
In the influence of Gravitational force, blood accumulates in the dependent parts of the body
The vessels looses tone due to stoppage of CNS.
If the dead body is left undisturbed, the staining starts in small patches by the end of first hour.
The small patches later coalesce to form uniform staining
Uniform staining takes 5-6 hours.
After 5-6 hours the lividity or hypostasis gets fixed.
Fixation of Lividity can be checked by blanching sign.
If blanching is present = non fixed lividity

Fixation of lividity

If the body is undisturbed, staining gets fixed
If body is disturbed after the fixation, staining will remain the same with slight change in the color
There will be no staining in the new area

Causes of Fixation of lividity:

After lividity, blood cannot be easily pass through the vessels
By end of staining, rigor mortis is established and the vessels are obliterated
After rigor mortis, vessels of the new area are also compressed.
There is diffusion of hemoglobin from haemolysed red cells in the stained areas.

General rule:

If the blanching happens, staining or lividity is not fixed and the time since death is less than 8 hours.
If there is no blanching, the time since death is more than 6 hours

Features of Post-mortem Lividity:

It is an intravascular phenomenon
Post-mortem lividity happens in the dependent part of the body
Color of livor mortis varies from red to purple (deoxyhemoglobin)
The area of the body in direct contact does not stains (contact pallor)
Antemortem lividity may be present in people with feeble circulation
Post-mortem lividity happens in internal organs also
It might confuse with contusion
Lividity in intestine may confuse with infarction
It is ruled out by signs of patchy appearance with areas of pallor. (called as vibices)
Glove and stock lividity:
- Happens in case of vertical death (hanging).
- Staining will be in hands and feet
- This pattern gives appearance of gloves and stockings.
In case of tight inner clothing, lividity happens in those areas
It does not appear over scar due to lack of blood vessels.
In case of drowning the lividity happens over head and upper parts of the body
Body in flowing water current may not show any lividity
Contact pallor may give rise to errors
Tight collars and ornaments may give impression of manual strangulation
Body lying supine in a crumpled blanket may give impression of bruises of assault.
Gordon and Shapiro observed that lividity may be formed along the sides of the neck.
Due to incomplete emptying of the superficial veins.
This should not be mistaken with bruises.
The differences between post-mortem lividity and bruises and post-mortem lividity and congestion are given below

Post Mortem lividity	Bruise
Due to engorged vessels showing through the skin	Due to rupture of the vessels either superficial or deep
On dependent parts and on front and sides of the neck in supine position	Situated anywhere (at site of blunt force trauma)
Margins clearly defined, usually horizontal	Margins are irregular, not horizontal
Uniform in color	May be variegated in color
No swelling	Swelling
No superimposed abrasion	Superimposed abrasion may be present
Incision shows few oozing points at the site of severed capillaries	Incision shows extravasated blood staining the surrounding tissues
Microscopically, the blood elements are found within the blood vessels and there is no signs of inflammation	Microscopically, the blood elements are found outside the blood vessels and there may be evidence of acute inflammation

Factors affecting Post Mortem lividity

Position: position of the body may change how lividity sets in.
Hemorrhage: hemorrhages can alter the intensity of the lividity
Anemia: this condition can cause very low intensity of lividity and sometimes difficult to assess
Complexion: darker complexion body may not show lividity very readily
Cold storage of the body: cold temperature leads to lividity to occur at a much slower rate.

Color and intensity of the lividity

Depends on color of blood and mode of death
Normally: bluish pink and bluish purple afterwards
In severe Anemia and hemorrhage: very faint
In asphyxia: purple in color
Lobar pneumonia: less obvious
Carbon monoxide poisoning: Bright cherry red
Cyanide: pink
Chlorates: chocolate brown
Phosphorus: dark brown
Nitrites: red brown
Hydrogen sulphide: bluish green
Opiates: almost black
Exposure to cold: cherry red.
Septic abortion: greyish brown

Medicolegal importance

Sign of death
Time since death may be estimated
Position of the body can be identified
The lividity in hands may confuse with cyanosis
May be confused with congestion
Cause of death can be identified
Blood dyscrasias/hemorrhagic spots may confuse with lividity
Lividity in intestines may confuse with infarction and strangulation

Changes in the muscles

The changes in the muscles are as follows:

1.Primary relaxation or primary flaccidity of the muscles

2.Rigor mortis

3.Secondary relaxation or secondary flaccidity

Primary flaccidity

Happens immediately after death
This stage last for 1-2 hours
Happens with somatic death
All the voluntary and involuntary muscles relax.
Jaw drops, pupils dilate, sphincters are relaxed
May result in incontinence of feces and urine
Molecular or cellular death has not occurred
Muscles may still respond to electrical and chemical stimuli
Tendon reaction or Zasko’s Phenomenon may be present
Pupils may react to atropine or physostigmine.
The muscles are still alkaline

Rigor Mortis

Also known as Cadaveric rigidity
Rigor = rigidity, Mortis = of death
Definition: “Rigor mortis is that state of muscles of dead body where they become stiff with some degree of shortening that follows the period of primary relaxation or flaccidity”
It is stiffening of muscles after death.
When developed completely, the joints and muscles become stiff and adopt a flexion attitude.
It indicates molecular and cellular death.

Forensic Anatomy and physiology of muscles

Each muscle fiber is a single cell (multi-nucleated)
It is surrounded by sarcolemma
The muscle fiber is made up of myofibrils
Myofibrils are made of filaments (thin=actin, thick=myosin)
Myofibrils are surrounded by sarcoplasmic reticulum.
The contraction of the muscle depends on
- Actin and myosin
- Tropomyosin and troponin (troponin I, T and C)

Sequence of contraction and relaxation

Initially there is discharge of motor neuron
This results in the release of acetylcholine
Then there is binding of acetylcholine to the receptor
This sets up an action potential by sodium-potassium pump
Which leads to depolarization resulting in the release of calcium from sarcoplasmic reticulum
Calcium binds to troponin C
This binding exposes the binding site
The exposure of the receptor site leads to gliding of actin over myosin and formation of cross-linkages
Ultimately resulting in muscle contraction

Mechanism of Relaxation

For relaxation to happen

The calcium is pumped back to SR (sarcoplasmic reticulum)
Then there is cessation of cross linkage between Actin and Myosin
Relaxation of muscles

For this whole process ATP is required

Mechanism of Rigor mortis

After somatic death, relaxation is maintained by stored glycogen
After depletion of glycogen stores ATP drops
There is formation of actin and myosin complex
This is a gel like structure that causes rigidity
This ultimately leads to rigor mortis
The muscles starts to become acidic due to lactic acid.
Rigor mortis persist till destruction of protein filaments due to autolysis.

Rigor mortis can be broken by mechanical force
If a limb is flexed forcibly, the limb becomes flaccid and remain so.
It is known as ‘breaking of Rigor mortis’
Note: Rigor mortis is broken in process of mobilization of body from the crime scene

Onset and disappearance of Rigor mortis:

It occurs early in involuntary muscles than voluntary muscles
In involuntary muscles it appears in the heart within an hour after death
Rigor mortis develops in the following order:
Muscles of eyelid: 3-4 hours
Muscles of the face: 4-5 hours
Neck and trunk: 5-7 hours
Muscles of upper extremities: 7-9 hours
Muscles of the leg: 11-12 hours
In the skin rigor mortis may present as ‘cutis anserina’
The rigidity passes of in the same order as it started.
In India rigor mortis starts in 2-3 hours
Rule of 12: takes 12 hours to develop, remain for 12 and goes in 12
This is called ‘march of rigor’

Factors influencing Rigor Mortis:

Age
Physique of the person
Season
Cause of death
Condition of the muscles

Medicolegal Importance of Rigor Mortis

It is a sign of death
Time since death can be estimated
May be confused with cadaveric spasm
Breaking of rigor can lead to errors
It is possible in paralyzed limb also
Position of the body can be estimated

Differential diagnosis and conditions stimulating Rigor mortis

Freezing or Cold stiffening
Heat coagulation or Heat stiffening
Putrefaction or Gas stiffening
Cadaveric spasm

Cold stiffening:

Happens when body is exposed to the freezing temperature
The tissues become solidified and stiff
After warming the body, the stiffness goes off and then Rigor sets in.
In modern mortuary, the body undergo cold stiffening due to solidification of body fat.

Heath coagulation or heat stiffening

Happens when body is subjected to extreme heat above 70 degree C
Found in death due to electrocution, falling in hot liquid, burning etc
The heat coagulates the proteins of the muscles and stiffness happens
Degree is more severe than normal rigor
In such cases Normal rigor does not set in.
The body adopts a Pugilistic attitude. Attitude of a boxer.
The stiffness will persist till putrefaction or decomposition.

Putrefaction or gas stiffening:

Stiffening happens due to accumulation of putrefactive gases
Causes false rigidity
Limbs will be stiff even without support.
Found in decomposed bodies.

Cadaveric spasm:

Also called instantaneous rigor, instant rigor, cataleptic rigidity
“Cadaveric spasm is a state where muscles or group of muscles, instead of going under primary relaxation after death, go into a sudden state of stiffening”.
This is a rare condition

Conditions necessary for its development:

Somatic death must occur with extreme rapidity
Person under emotional tension
Muscles must be in physical activity

In cadaveric spasm certain group of muscles do not undergo primary relaxation.
It involves only certain group of muscles
Body may be found holding a knife, a gun or hair (in homicide) or weeds or grass in case of drowning.
Such findings are not found in rigor mortis
The cadaveric spasm is more pronounced than rigor mortis.
It can be broken only due to putrefaction.

Medico-legal importance:

It indicates sudden death associated with emotional tension
It indicates the muscles in physical activity
It may indicates nature of death.

Secondary Relaxation

It involves secondary relaxation of muscles followed by rigor mortis
Muscles become flaccid and soft. The muscle reaction is alkaline
There is no response to mechanical, electrical or chemical stimuli

Difference between Rigor mortis and heat stiffening:

Features	Rigor Mortis	Heat stiffening
Nature	Post mortem	May be antemortem or post mortem
Degree of Stiffness	Comparatively moderate	Comparatively high
Mechanism	Breakdown of ATP	Due to coagulation of muscles
Associated features	Nothing specific	Signs of exposure to heat will be present like blisters, burning, heat ruptures etc.

Difference between Rigor mortis and cadaveric spasm:

Features	Rigor mortis	Cadaveric spasm
Time of onset	1-2 hours after death	Immediate
Muscles involved	All muscles are involved	Usually group of muscles like hand
Degree of stiffness	Comparatively moderate	Comparatively strong
Predisposing factors	None	Excitement, fear, emotional disturbance
Mechanism	Breakdown of ATP	Not known
Medicolegal importance	Helps to know time since death, position of the body	Helps to suggest manner of death