Chapter 13: Thanatology

13.1: Introduction

• Thanatology — %%study of death%% among human beings.
  • It also describes bodily changes that accompany death and the after-death period.
  • It is a subject that deals with scientific study of death, types of death, the various events, or changes that occur in the cadaver after death and their medico-legal significance.
• Harvard Ad hoc Committee on Brain Death — published a report describing the following characteristics of a permanently non-functioning brain, a condition it referred to as “irreversible coma,” now known as brain death:
  • Unreceptively and unresponsitivity — patient shows total unawareness to external stimuli and unresponsiveness to painful stimuli.
  • No movements or breathing — all spontaneous muscular movement, spontaneous respiration are absent.
  • No reflexes — fixed, dilated pupils; lack of eye movement even when hit or turned, or ice water is placed in the ear; lack of response to noxious stimuli; unelicitable tendon reflexes.

13.2: Definitions of Death

• The Black’s Law Dictionary defines death as ‘the cessation of life.’
• The Chamber’s Twentieth Century Dictionary, defines death as ‘the extinction of life’.
• Clinically, death is defined as the irreversible cessation of life.
• Physicians declare death with cessation of all vital functions such as nervous, circulatory and respiratory systems.
• Death is a process not an event and, while the cells of some tissues are still alive and even capable of movement, others are dying or dead.

Main Types of Death

1. Somatic Death — the %%irreversible cessation of functioning of the brain, heart and lungs%%, resulting in complete loss of sensibility and ability to move the body.
   • In somatic death, though life has ceased in the body as a whole, it still persists in its component parts, namely the tissues and cells.
     • Cessations of heart beating – by careful auscultation of precordium for the heart sounds by a stethoscope continuously, for 5 minutes, and then repeating it thrice, at an interval of 5 minutes. A flat ECG may also confirm it.
     • Cessation of breathing – by thorough auscultation of the chest for the breath sounds using a stethoscope.
     • Cessation of brain activity – by the dilated fixed pupil and absence of pupillary and corneal reflexes. A flat Electroencephalogram (EEG) would confirm it.
2. Molecular Death — %%ultimate death of all cellular elements%%.
   • It can be confirmed by absence of any response to an electrical, thermal or chemical stimulus in the tissues.

13.3: Brain Stem Death and Organ Transplantation

Cerebral/Cortical Death

• The brain stem is intact, with continuous heart sounds and respiration, but %%total loss of sentient activity%%.
• Severe brain damage may result in a persistent vegetative state (PVS).
• These patients breathe spontaneously, open and close their eyes, swallow and make facial grimaces. It is in these cases that the moral dilemma of allowing someone to die (euthanasia) arises.
• Causes: Cerebral hypoxia, toxic conditions, widespread brain injury, etc.

Brain Stem Death

• The %%cerebrum is intact, but cut off functionally%%.
• When the brain stem is dead, the person becomes irreversibly unconscious and irreversibly apneic.
• The dilemma of euthanasia does not apply to those who are brain stem dead. These patients are irreversibly and unequivocally dead.
• After brain stem death is established, retention of the patient on ventilator, undoubtedly facilitates a fully oxygenated ‘cadaver transplants’, the so called ‘beating-heart donor’.
• Causes: Cerebral edema, increased intracranial pressure, etc.

Whole Brain Dead

• It comprises a %%combination of both cortical and brain stem death%%.
• Clinical definition of death has been now modified as irreversible state of coma consisting of:
  • Deep state of unconsciousness with no response to external stimuli/internal need.
  • No movements, no spontaneous breathing.
  • Cessation of spontaneous cardiac activity without assistance. • No reflexes.
  • Bilateral dilated fixed pupils.
  • A flat isoelectric EEG is needed.
  • No profound abnormalities of serum electrolytes, acid-base balance or blood glucose.

13.4: Modes of Death

Syncope (Fainting)

• Syncope — a result of %%sudden stoppage of functioning of the heart,%% which may prove fatal.
• It is due to vasovagal attacks resulting from reflex parasympathetic stimulation, reflex bradycardia or asystole, or by reflex splanchnic vasodilatation.
• Sudden stoppage of the functioning of the heart can also result in ischemia of vital centers of the brain and ultimately death.
• Causes:
  • Anemia due to sudden and excessive hemorrhage.
  • Asthenia due to deficient power of heart muscle.
  • Myocardial infarction
  • Exhausting diseases
  • Poisoning with cardiac poisons
  • Reflex cardiac inhibition
  • Death resulting so, is called instantaneous physiologic death, vasovagal shock, vagal inhibition or neurogenic shock.
• Clinical Features:
  • Pallor of lips, face,
  • Dimness of vision,
  • Dilated pupils,
  • Skin-cold with perspiration,
  • Gasping respiration,
  • Nausea-vomiting,
  • Weak, slow pulse, fall of BP,
  • Delirium,
  • Convulsion and death.

Asphyxia

• Asphyxia — a condition resulting from %%interference with respiration or sudden stoppage of functioning of the lung%% causing unconsciousness or death.
• Sudden stoppage of or failure of functioning of the lungs can lead to impaired blood oxygenation leading to tissue anoxia.
• Subnormal blood supply to the brain causes rapid unconsciousness.
• The brain is highly sensitive to oxygen deprivation, which results in failure of vital centers and ultimately death.
• Gordon’s Hypothesis — emphasizes the fact that tissue anoxia, irrespective of its origin can invariably lead to the cessation of vital functions, especially circulatory failure resulting in death.

Four Types of Anoxia

1. Anoxic anoxia: This is mainly %%due to mechanical asphyxia leading to defective oxygenation in lungs.%%

   1. Here the lungs are normal, blood and blood circulation is normal, but due to the mechanical asphyxia, %%respiration is difficult and entry of oxygen into the lung is impaired%%, resulting in defective oxygenation of the tissues.
   2. Examples: Hanging, strangulation, suffocation, choking, drowning, high altitudes.

2. Anemic anoxia: This is mainly due to the %%reduced oxygen carrying capacity of blood%%.

   1. Here though the lungs and blood circulation both are normal, the %%defects are in the circulating blood%% both in its quantity and in quality which results in defective oxygenation.
   2. Examples: Exsanguinations, CO poisoning, etc.

3. Histotoxic anoxia: This is mainly due to the %%depression of tissue oxidation%%.

   1. Here the lungs and blood circulation are normal, but %%due to the impairment of cytochrome oxidase enzyme, the tissues are unable to utilize oxygen%%.
   2. Example: Cyanide poisoning.

4. Stagnant anoxia: This is mainly due to the %%inefficient circulation of blood%%.

   1. Here though the lungs are normal and blood in circulation is normal the circulation is inefficient; hence %%oxygenation is improperly taking place%%.
   2. Examples: Congestive cardiac failure, traumatic shock, heat stroke, etc.

Clinical Features of Asphyxia:

1. Stage of dyspnea: This is due to %%excess accumulation of carbon dioxide%%, which stimulates the respiratory center resulting in increased rate and amplitude of respiratory movements.
2. Stage of convulsions: This is due to %%lack of oxygen%% and the victim will show labored respiration, clouding of consciousness, convulsions, sphincteric relaxation, etc.
3. Stage of exhaustion and respiratory failure: It lasts for 2 to 3 minutes. %%Respiratory and other nervous centers are completely paralyzed%%.

Coma

• Coma — results from %%sudden stoppage of functioning of the brain%%.
• It is a state of unarousable unconsciousness determined by absence of any psychologically understandable response to external stimuli or inner need.
• It is due to paralysis or insensibility of central portion or vital centers of the brainstem.
• Causes:
  • Compression of brain due to diseases and injuries of brain or its membranes, e.g. intracranial hemorrhage, inflammation, abscess, or neoplasm of the brain.
  • Acute poisonings with opium, cocaine, chloral hydrate, anesthetics, barbiturate, alcohol, etc. having specific depressor action on brain and nervous system.
  • Metabolic disorders and infections—uremia, eclampsia, diabetes, chloremia, acetonemia, pneumonia, infectious fevers, heat stroke, etc.
  • Other causes – embolism and thrombosis in cerebral vessels, epilepsy, hysteria, etc.

13.5: Manner of Death

• Manner of death — explains %%how the cause of death came about.%% It is generally considered to be natural, homicide, suicide, accident, and undetermined.
• Manner of death is ‘undetermined’, when the facts are insufficient about circumstances surrounding the death, or when the %%cause of death is unknown%%.
• Suicide, accident, homicide, natural and undetermined, some people use the term ‘unclassified’. This also refers to death in which the %%cause and circumstances are not know%%n.
• Agonal Period: It is the %%time between a lethal occurrence and death%%.
• Time of Death: The time at which brain stem death is established. This does not coincide with the time when the ventilator is switched off; or heartbeat ceases.

13.6: Mechanism of Death

• Mechanism of Death — it is the %%physiological or biochemical derangement produced by the cause of death%%, which is incompatible with life and results in death.
• The mechanism of death could be, hemorrhage, septicemia, cardiac arrhythmias, etc.
• If an individual dies of a massive hemorrhage, it can be produced by a gunshot wound, a stab wound, a malignant tumor of the lung eroding into a blood vessel, and so forth.

13.7: Cause of Death

• Cause of Death — the %%disease or injury that produces a physiological derangement in the body%% that results in death of the individual.
• Immediate cause — the %%actual cause at the time of terminal event%%, e.g. bronchopneumonia, peritonitis, trauma, etc.
• Antecedent cause — the %%actual pathological process responsible for the death%% at the time of the terminal event or prior to or leading to the event, e.g. gunshot wound of abdomen complicated by generalized peritonitis.
• Contributory cause — the %%pathological process involved in or complications%%, but not causing the terminal event, e.g. Carcinoma stomach.

13.8: Medicolegal Importance of Death

• Death and the Indian Penal Code (IPC): Section 46, IPC, states the fact that the word ‘death’ denotes death of a human being unless the contrary appears from this context.

• Disposal of the Body: During cremation of a dead body immediately after somatic death, spontaneous movements of hand or feet may be observed in the cadaver on the funeral pyre, creating an impression that the person is not actually dead and the disposal is premature.

• Tissue and Organ Transplantation: Viability of transplantable tissues and organs falls sharply after somatic death; a liver must be removed within 15 minutes, kidney within 45 minutes and heart within an hour.

• Question of Presumption of Survivorship: When two or more persons die at almost the same time, or by a common accident, the question may arise who survived the longest; and if no direct evidence on this point is available the question becomes one of presumption of survivorship.

• Issuing of Death Certificate: This is issued after everything are tested; the cause of death are determined; and the important information about the dead is provided.

13.9: Sudden Death

Causes

• It is where a natural death is very rapid, perhaps virtually instantaneous, the cause is invariably cardiovascular.
• If a person collapses and is clinically dead when someone nearby runs to assist him, this can only be a cardiac arrest, as virtually no other mode of death operates so quickly.
• Extracardiac causes, even still in the cardiovascular system, are rarely so rapidly fatal, though death in minutes is common.
• Sudden death may occur from both natural and unnatural causes or from a combination of both.

Cardiovascular System

• A lesion that causes most of the sudden unexpected deaths (SUD) is usually in the cardiovascular system, even if the vessel concerned lies anatomically in the brain or abdomen.
• The following lesions are most obvious:
  • Coronary artery diseases
  • Congenital heart diseases
  • Valvular heart diseases
  • Hypertensive diseases
  • Infections
  • Cardiac tamponade — constitutes a lesion wherein ruptured myocardial infarct, trauma, etc. results in collection of blood in the pericardial sac.
  • Obscure conditions such as cardiomyopathies, Fiedler’s myocarditis, etc.
  • Aortic aneurysms of atherosclerotic or dissecting type.

Respiratory System

• Pulmonary embolism is a common and in fact is the most under-diagnosed cause of death.
• The source of emboli is in the leg veins, as pelvic thrombosis is very rare.
• Various causes of sudden natural death of respiratory system origin are:
  • Pulmonary embolisms
  • Massive hemoptysis
  • Severe infections
  • Chronic asthma/status asthmatics
  • Anaphylaxis
  • Obstruction of respiratory tract.

Intracranial Vascular Lesions

• Commonly encountered intravascular lesions resulting in sudden natural death are:
  • Intracranial bleeding due to cerebral atheroma and stroke or hypertension
  • Subarachnoid hemorrhage from ruptured aneurysm
  • Cerebral thrombosis
  • Embolisms
  • Infections of meningitis
  • Brain tumors
  • Idiopathic epilepsy
  • Functional inhibition of the vagus nerve.

Psychiatric Patients

• Sudden, unexpected death may also occur in psychiatric patients, has raised the concern that the use of psychotropics, especially antipsychotics, may be associated with an increased risk for sudden death.
• This concern is maintained even though not all psychiatric patients who have succumbed to sudden death have been on psychotropic.

Gastrointestinal System

• The major cause of sudden death within the gastrointestinal system may once again be mentioned to be mostly of vascular origin and they are:
  • Severe gastrointestinal bleeding due to gastric or duodenal ulcers
  • Ulcerative colitis, malignancies, etc. can be fatal in a short- time, even though most are moderate enough to allow medical or surgical treatment
  • Mesenteric thrombosis and embolism leading to infarction of the gut are not sudden, but may be rapid and remain undiagnosed
  • Perforation of peptic ulcer can be fatal in hours if not treated
  • Intestinal gangrene due to strangulated hernias and torsion due to peritoneal adhesions can be a fulminant and fatal condition
  • Aortic aneurysmal rupture
  • Diseased viscera undergoing rupture
  • Fulminant hepatic failure
  • Acute hemorrhagic pancreatitis.

Gynecological Conditions

• If a women in her child bearing age is found to be dead unexpectedly and suddenly, following may be considered as cause of death:
  • Complication of pregnancy must be first thought of, just to make a primary exclusion.
  • Hemorrhage in female genital organs could be due to abortion or ruptured ectopic pregnancy, etc. and is a grave emergency that can result in death from intraperitoneal bleeding, unless rapidly treated by surgical intervention.

Endocrinal Causes

• Sudden natural deaths occur due to any one of the following:
  • Adrenal insufficiency
  • Diabetic coma
  • Myxedemic crisis
  • Parathyroid crisis

Iatrogenic Causes

• Following may be suspected and may have to be ruled out:
  • Abuse of drugs
  • Sudden withdrawal of steroids
  • Anesthesia
  • Mismatched blood transfusion.

Special Causes in Children

• If the victim happens to be a child following may have to be thought and ruled out, namely SIDS (sudden infant death syndrome), cot deaths, Mongol’s and other types of congenital or mental disorders concealed puncture wounds, indeterminate – very rarely.

13.10: Changes After Death

1. Immediate Changes
   • Insensibility
   • Respiratory arrest
   • Circulatory arrest
2. Early Changes
   • Postmortem cooling
   • Eye changes
   • Skin changes
   • Postmortem lividity
   • Muscle changes
3. Late Changes
   • Putrefaction
   • Adipocere formation
   • Mummification
   • Skeletonization

13.11: Insensibility

• Insensibility — comprises %%complete loss of response to sensation%%.
  • Test for confirming insensibility — A flat EEG or loss of EEG rhythm.

Respiratory Arrest

• It is the %%complete stoppage of respiration for more than 3 minutes.%%
• Tests for confirming cessation of breathing:
  • Feather test – no movement of a feather held in front of the nose.
  • Mirror test – a mirror held in front of the nose does not turn dim due to any moisture of breath.
  • Winslow’s test – no movement of surface of water in bowl kept on the chest.

Circulatory Arrest

• It is the %%complete absence of heart sounds for more than 3 to 5 minutes%%.
• Tests for confirming cessation of circulation:
  • Magnus’s test (Ligature test) — fingers fail to show congestion distal to a ligature applied at their base.
  • Diaphanous test (Transillumination test) — Failure to show redness in the web space between the fingers on transillumination from behind.
  • Icard’s test — fluorescent dye on being injected at a given site in a dead body fails to produce any discoloration.
  • Fingernail test — no blanching and filling of blood in the fingernail on application of pressure and release.

13.12: Suspended Animation (Apparent Death)

• Suspended animation — a condition, wherein the %%vital functions of the body are maintained at a low pitch reduced to a minimum%% for some time, that they cannot be detected by routine methods of clinical examination.
  • Voluntary SA — happens from yoga practice.
  • Involuntary SA — happens in newborn infants, insanity, drowning, electrocution, cholera, frozen coma, after anesthesia, typhoid state, shock, sun-stroke, etc.

13.13: Postmortem Cooling and Caloricity

• Postmortem Cooling — %%cooling of the dead body%%.
• Postmortem Caloricity — an %%initial rise of the temperature of the body after death%%.

Measuring the Cadaveric Temperature

1. By measuring the rectal temperature by introducing the bulb, 8 to 10 cm deep into the rectum.
2. By measuring the inner core body temperature by placing the bulb in contact with the inferior surface of liver through a midline incision.
3. By measuring vaginal temperature by inserting the bulb 8 to 10 cm deep into the vagina.

Rate of Cooling

• In temperate climate, the cooling rate is:
  • In first 2 to 3 hours there is no cooling
  • In the next 6 hours it is about 1.5°C/hour
  • In later 6 to 12 hours it is about 0.9°C to 1.2°C/hour.
• Graphical method of calculation of PMI: Record at least 3-4 temperature readings at 0.5 to 1 hour intervals and plot a graph with temperature v/s time. The interval at which it cuts 37.2°C is the postmortem interval (PMI).

Factors Controlling Rate of Cooling

• Age: The bodies of young and middle-aged people that are relatively bigger, cool more slowly than bodies of children and old-aged people.
• Condition of the body: Obese and well-nourished large bodies retains heat for long time.
• Initial body temperature: Higher temperature takes a long time in cooling.
• Position of the body: Bodies in a supine/prone position cool more rapidly than bodies in a crouched position.
• Manner of death: Cooling of the body is more rapid in deaths due to chronic, wasting diseases than in deaths due to accident or acute disease or apoplexy.
• Clothing: Bodies covered with thick garments cool slowly.
• Atmospheric temperature: Bodies in warm/hot atmosphere, cooling is delayed.
• Size of the room: Bodies in a small, ill-ventilated room, cooling is delayed.
• Medium in which the body lies: Bodies immersed in running water cools rapidly than when exposed to air.

13.14: Post Mortem Lividity

• Postmortem lividity — the %%purplish or reddish purple areas of discoloration of skin%% and organs after death due to accumulation of blood in dependent parts of the body and seen through the skin.
• After death, blood in its fluid state gravitates into the toneless capillaries and venules of the ‘rete mucosum’ in the dependent parts of the body and causes capillo venous distension, which through the skin imparts a discoloration to the area involved.
• The lividity appears by 1 to 3 hours of death.
• In a dead body lying on the back, it will be evident in the posterior portion of the cerebral lobes, cerebellum, in pial vessels in the posterior fossa, posterior surface of heart, lungs, liver, kidneys, spleen, larynx, stomach and intestines.

Medicolegal Importance of Postmortem Lividity

• Can assess time since death.
• Can decide the position of the deceased at the time of death.
• It may be mistaken for a contusion.
• Can establish the cause of death.

13.15: Rigor Mortis

• Rigor Mortis — the postmortem %%stiffening/rigidity of the muscles in a dead body%%.
• It is basically due to the depletion of adenosine triphosphate (ATP) reserve from the muscle.
  • ATP is the %%main source of energy for muscle contraction%%.
  • Muscle needs a continuous supply of ATP to contract because the amount of ATP present in muscles is sufficient to sustain muscle contractions for only a few seconds.
  • After death, generation of ATP stops, though consumption continues.
• Instantaneous Rigor — A rare condition in which e%%xtremely rapid muscle stiffening occurs after cardiac arrest%%.
• Rigor mortis disappears with onset of decomposition.
• Testing for rigor in cadaver is done by trying to open eyelids, depressing the jaw, gently bending the neck and various joints of the body and noting the degree and distribution.
  • Upper part of body — stiffens by about 7 to 9 hours of death.
  • Whole body — stiffens by 11 to 12 hours of death.
• Primary Flaccidity: Immediately after death, as the control from brain on each of the muscles is lost and every muscle of the body shows complete relaxation.
• Secondary Flaccidity: When the molecular death has occurred in each of the actin and myosin filaments, the muscular stiffness that had developed earlier in the previous stage will begin to disappear slowly and gradually, relaxing the body back to its original state.
• Rigor mortis sets on within %%1 to 2 hours after death%%, and is well developed from head to toes in about 12 hours.

Conditions Resembling Rigor Mortis

• Cadaveric spasm — condition wherein %%stiffening occurs in certain groups of muscles%%, which were already in a state of contraction at the time of death.
• Heat stiffening: The attitude of a boxer in self-defense - taken up by the body in death, %%due to heat coagulation of muscle proteins%%.
• Cold stiffening: Here muscles are %%stiff due to solidification of fat and freezing of body fluid%% due to the extreme cold.
• Gas stiffening — this is due to %%accumulation of putrefaction gasses in the tissues so as to cause a false rigidity%% resulting in stiff limbs.

Factors Affecting Rigor Mortis

• Diseases: Wasting disease or any condition leading to extreme exhaustion—rapid onset of rigor mortis, followed by rapid passing off of the same, lasting for a short duration.
• Health: In a healthy person, onset of rigor mortis is slow. It also passes off slowly, lasting for a longer duration.
• Age: In old age, starts early, lasts for a short duration, and passes off quickly.
• Temperature: In warmer temperatures, onset and disappearance are both hastened.
  • In colder temperature onset and disappearance are both retarded.
• Eye: Iris is affected so that ante-mortem constriction or dilatation is modified.
• Heart: Rigor of heart causes the ventricles to contract, which may mimic and look like left ventricular hypertrophy.
• Skin: Rigor in the erector pili muscles in the skin, can cause a dimpling effect or ‘goose–flesh’ appearance with elevation of the extraneous hairs.

13.16: Postmortem Decomposition

• Decomposition involves two processes: autolysis and putrefaction.
• Decomposition differs from body to body, from the environment to environment and even from one part of the body to another in a corpse.
• Autolysis — self-destruction.
  • It is responsible for lysis of the tissues. It is therefore a completely aseptic chemical process and organs rich in enzymes undergo autolysis earlier than organs with less amounts of the enzymes.
  • In molecular death, cell death is ultimate and with this, each cell release certain enzymes, which are responsible for the lysis of the tissues.
  • Time required for autolysis: Usually it commences within 3 to 4 hours of death and completes in about 2 to 3 days or few more days.

13.17: Putrefaction

• Putrefaction — the final process observed in the cadaver, leading to the gradual dissolution and liquefaction of the tissues.
• This to most of the forensic experts is though synonymous with decomposition, is due to bacterial fermentation.
• Bacterial Action: Certain bacteria can produce proteolytic and other enzymes, mainly lecithinase which are capable of bringing lysis of tissues. Factors favoring bacterial action are:
  • Marked increase in tissue hydrogen ions
  • Rapid decrease in tissue oxygen levels
  • Presence of adequate moisture in the body
  • Conveniently warm atmospheric temperature (70°-100°F).

External changes

• Color changes of skin:
  • The first external evidence of putrefaction in a dead body, exposed to air is the formation of greenish blue /greenish black discoloration of the skin in localized areas.
  • In case of decomposition in air — the color changes appear in an order of the abdomen, chest, face, legs, shoulders, arms.
  • In case of decomposition inside water — the color changes appear in an order of face, neck, thorax, shoulder, arms, abdomen and legs.
  • PMI: Over right iliac fossa and flanks—12 to 24 hours.
  • PMI: Whole body—48 hours.
• Marbling of skin: This is a color change scene in the form of mosaic like pattern on the skin on certain parts of a cadaver where the veins converge.
• Evolution of foul-smelling gases
  • As the color changes commences over the abdomen, the body gradually starts emitting unpleasant and offensive the smell due to formation and collection of decomposition gases by the breaking down of body proteins and carbohydrates within and 12 to 18 hours of that in summer.
  • These gases include:
    • Hydrogen sulfide
    • Ammonia
    • Phosphorated hydrogen
    • Methane
    • Marsh gas
• Appearance of maggots: Maggots start to appear on different parts of the body.

13.18: Cadaveric Entomology

• Any putrefying human body %%attracts house flies%% (Musa) and such other insects easily.
• These flies may lay their eggs on fresh corpses, between the lips, or the eyelids, in the nostrils, genitalia, or in the margin of a fresh wound, within a few minutes after death, and in some cases even before death during the agonal period.
• When the skin decomposition begins, the eggs can be deposited anywhere.
• The maggots can %%burrow under the skin and make tunnels and sinuses, which hasten putrefaction%% by allowing air and bacteria.

Colliquative Putrefaction

• Here the wall of the abdomen softens and bursts open with protrusion of the stomach and intestines.
• The thorax also bursts, especially in children.
• The diaphragm is pushed upwards.
• The body fats especially the omental, mesenteric, and perirenal may liquefy into a translucent yellow fluid filling body cavities between organs.
• The tissues become soft, and loose and are converted into a thick,
• semi-fluid, black mass, to fall off separately, exposing the bones.
• The cartilage and ligaments are similarly softened.
• Colliquative putrefaction and time since death—It usually commences on the fifth day after death and is complete by the tenth day.

Rapidly Putrefying Organs

• Larynx and trachea
• Brain of infants
• Stomach, intestines, and spleen
• Liver (change called foamy liver) and lungs
• Adult brain
• Pancreas

Slowly Putrefying Organs

• Heart
• Kidneys, bladder, uterus (gravid)
• Skin, muscles, and tendons
• Blood vessels
• Uterus (nulliparous) and prostate.

Conditions Influencing Putrefaction

1. Condition of Body
   • Fat, flabby body with heavy clothing, sepsis, and the presence of plenty of moisture - hasten putrefaction.
   • Newborn infant — putrefaction is slow.
   • Slim and lean body with tight clothing, body lying on a stone or metallic surface, which can cool rapidly by conduction can retard putrefaction.
   • Embalmed cadavers — dead bodies are embalmed to delay decomposition.
2. Cause of Death
   • Death by septic diseases, puerperal sepsis, kidney diseases with generalized (anasarca) edema, etc. can hasten putrefaction.
   • Death by chronic alcoholism can retard putrefaction.
   • Death by poisons such as potassium cyanide, barbiturates, fluoride, phosphorous, endrin, datura, strychnine, yellow oleander, nicotine, arsenic, mercury, copper, antimony, lead, thallium, etc. can resist putrefaction.
3. The Surrounding Atmosphere
   • Airtight coffin buried deep (>2 meters)
   • Death in utero, with intact membranes
   • Too high temperature (>48°C)
   • Too low temperature (<0°C)
   • Body is immersed in water, where no air enters.
4. The Medium in which the Body Lies
5. Putrefaction in Water: It is slower than on ground, because of lower ambient temperature, non-availability of air and protection from insect and small animal predators.
   • First week: Little changes are seen.
   • Second week: changes begins to appear in face, neck, etc. in bodies floating supine, as these parts are exposed to air, rendering identification of face difficult.
   • 2-6 weeks: The distension of abdomen, skin peels off now.
   • 6-8 weeks: The whole body becomes discolored and postmortem blisters or bullae of gas are formed.
   • 3rd month: putrefaction continues.
   • Floating of dead body—this occurs within 12-20 hours in summer, as a result of accumulation of gases in the body tissues, which makes it lighter. It will sink again on escape of gases.
6. Destruction by Animals
   • Dogs, fish, ants, etc. can eat the dead body, especially around natural orifices, such as nostrils, mouth, anus, vaginal orifice, etc. and eyes.
   • Pseudoabrasion: The animal eaten parts of the body may be mistaken for antemortem injuries.

13.19: Skeletonization

• Skeletonization — the %%complete decomposition of the non-bony tissues of a corpse%%, leading to a bare skeleton.
• In a temperate climate, it usually requires %%three months to several years%% for a body to completely decompose into a skeleton, depending on factors such as temperature, the presence of insects, and submergence in a substrate such as water.
• In the tropics, skeletonization can %%occur in weeks%%.
• In the Andes Mountains or Tundra, skeletonization will %%never occur if subzero temperatures persist%%.
• After skeletonization has occurred, the human skeleton takes about %%twenty years under optimal conditions to be completely dissolved by acids%% in the soil leaving no trace of the organism.
• In neutral pH soil or sand, the skeleton will persist for at least several thousand years before it finally disintegrates.

The process of skeletonization takes varied time under varied conditions.

• A %%body exposed to air, will get completely skeletonized from decomposition by 14-20 days,%% but the time limit may be less, if exposed to ants, flies, maggots, cockroaches, rats, vultures, dogs, jackals, etc in addition.
• A buried body %%laid down in a coffin will take more than a year to get skeletonized%%, depending upon the coffin material and place of burial, etc.
• An %%unconfined buried body in ordinary conditions in a tropical place%% will get skeletonized within %%six months maximum%%.
• In case of %%mass grave and shallow burial%%, the unconfined body will get %%skeletonized within a week or two%%.
• After skeletonization, the %%bones usually decompose by 3 to 5 years%% or more; these will ultimately %%crumble to dust leaving no trace of it within 10-15 years%%.
• Decomposing bones lose weight and become fragile from loss of organic matter.
• A %%body dying outdoors in winter will ‘survive’ longer%% than one dying in summer.

13.20: Estimation of Post Mortem Interval

• Changes in Gastrointestinal and Urinary Tract
  • Stomach contains undigested food particles — since digestion of food requires 2 to 3 hours normally, presence of undigested food particles in the stomach suggests the deceased must have died after taking food.
  • Fully distended urinary bladder —normally at night the bladder gets fully distended, as people do not get up frequently to urinate once asleep.
• Changes in Biological Fluids
  • Vitreous humor potassium level: It is reported to increase after death.
  • CSF chloride level: It is found to decrease and a concentration below 440 mg percent indicates PMI to be less than 25 hours.
  • Blood creatinine value: It is found to increase after death. A concentration of 5 mg percent indicates PMI to be less than 10 hours, while values of 11 mg percent indicate PMI to be less than 28 hours.
• Hair and nails present an apparent growth after death, due to drying up of the skin after death, which could help in establishing PMI or time since last shave.
• Carbon Dating
  • Radioactive carbon (C-14) — formed in atmosphere by the action of cosmic radiation and enters all living beings through various channels, it gradually diminishes after death.

13.21: Conditions that Replace Putrefaction

Adipocere Information

• Adipocere formation — a modified process of putrefaction, %%wherein the fatty tissues of the body change into a substance known as adipocere%%, by hydrolysis and hydrogenation.
• Factors Influencing:
  • Cold weather-retards
  • Hot weather-accelerates.
• Properties of Adipocere
  • Odor — it has an ammoniacal odor initially, which gets later on replaced with a distinct rancid/sweetish odor.
  • Fresh adipocere on touch — is soft, moist, greasy and waxy. It becomes dry, brittle, chalky and friable in months/years after time of formation.
  • Color — varies from dead white to grayish white or brown.
  • Inflammability — it is inflammable and burns with yellow flame.
  • Solubility — it is insoluble in water, but dissolves in alcohol and ether.
  • Distribution — It is generally distributed in all sites wherever fatty tissue is present, such as subcutaneous fat.
  • Chemically — adipocere contains palmitic, oleic and stearic fatty acids together with glycerol.
  • Adipocere formation is often mixed with other forms of decomposition.
• Time required for adipocere formation: 3 weeks time in summer temperate zones.

Mummification

• Mummification — a modified process of putrefaction, wherein the water content in the dead body gets evaporated making it dehydrated or desiccated and shriveled up, the natural appearances and features of the body are retained.

• Factors influencing: Body in dry place with warm, dry air circulation.

• Appearance: Whole body gets converted into a hard, dry, leathery mass and the features will remain as they are.

• Time required—several weeks.

Maceration

• Maceration — is due to %%autolysis in an aseptic environment%%. When a fetus dies in the uterus naturally, it will be in a sterile medium in the amniotic fluid.
• The body becomes
  • Discolored – brownish-pink after exposure to air.
  • Skin is peeled off and slimy.
  • Arms flaccid and frail.
• Time required: 48-72 hours after IUD.

13.22: Process of Preserving the Dead Body

• Embalming: This process renders the proteins to get coagulated, tissues fixed, organs bleached and hardened, blood coagulated and converted into pinkish-brown mass.

  • If proper embalming is done soon after death, the decomposition can be withheld for a long time; even maybe for months.

• Freezing: If a body is kept in deep freeze or amidst thick layers of ice, it can remain in good preservation for a long time.

  • Bodies left frozen in ice caves in arctic circles can remain preserved indefinitely.

• Taxidermy: This process can be adapted for preservation of the dead body, especially when it is to be taken from one place to another for burial or to avoid putrefaction before cremation or burial, which might take some time.

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