Death is defined as the permanent and irreversible cessation of vital functions in the body. There are two types of death - somatic death, which is the complete stoppage of vital functions, and cellular death, which is the cessation of respiration and metabolism in individual cells after somatic death. The three modes of death relate to the failure of the nervous, circulatory, or respiratory systems, known as the "tripod of life". Signs of death include immediate signs like insensibility and loss of brain waves at somatic death, early signs like skin changes and muscle rigidity at cellular death, and late signs like decomposition.

1. Death: Modes and Signs
Definition of death:
Death means “Cessation of life or ceasing to exist”. Physician’s conception of death is
“Total stoppage of circulation with consequent cessation of vital functions of the living
body”.
Medico logical definition of death- “Death is permanent and irreversible cessation of
functions of the three interlinked vital system of the body (the tripod of life), namely, the
nervous, circulatory and respiratory system”.
Types or Phases of Death:
Death may be divided into somatic and cellular death.
o Somatic death (systemic death): means that the person no longer functions as a
unit of society, because he is irreversibly unconscious and therefore cannot
communicate with the environment and is unaware of his own or the world’s
existence. In short, somatic death is the complete and irreversible stoppage of the
vital functions.
o Cellular death (molecular death): means the cessation of respiration and
metabolism of the body tissues, which is soon followed by autolysis and decay.
This is the death of tissues and cells individually, which takes place usually
2 to 3 hours after the somatic death. This is indisputably true death when it affects
the whole body, but almost never occur explosion.
Difference between Somatic and Molecular death:
Somatic death Molecular death
1. Complete & continuous cessation of the
vital function of three important organs,
i.e. brain, heart & lungs.
1. Individual cell death takes place due to
lack of Oxygen supply.
2. It proceeds to molecular death. 2. It follows somatic death.
3. It may be confused with suspended
animation.
3. No chance to be confused.
4. Muscles respond to electric stimuli. 4. Muscles do not respond to electric
stimuli.
5. At this stage, organs can be removed
for transplantation.
5. At this stage, organs can not be
removed for transplantation.
BRAIN DEATH (BRAIN STEM DEATH)
Brain death means that the patient is dead, whether or not the function of some organs,
such as a heart beat is maintained by artificial means and all the functions of the brain
must have permanently and irreversibly ceased.

2. Signs of death
A. IMMEDIATE
1) Insensibility and loss of EEG
rhythms.
2) Cessation of circulation (i.e. ECG
rhythms)
3) Cessation of respiration.
4) Cadaveric spasm.
Somatic death.
B. EARLY
1) Cooling
2) Skin changes
3) Eye changes
4) Blood changes
 Hypostasis
 Fibrinolysis
 Post-mortem bleeding
5) Chemical changes in body fluids.
6) Muscular changes- Rigor mortis.
Cellular death
Early reliable signs
C. LATE (reliable signs)
1) Putrefaction
 In air
 In water
 In earth
2) Adipocere formation.
3) Mummification.
4) Larval infestation.
Decomposition and decay.
Modes of death:
The term ‘modes of death’ refers to the system which initiates death. In all forms of
death, there are three modes of death relating to three systems, which are called ‘tripod of
life’
These modes are:
1) Coma (failure of the nervous system)
2) Syncope ( failure of the circulatory system)
3) Asphyxia ( failure of the respiratory system)
Coma:
Coma means insensibility resulting in death from different cause which involves the vital
centers of the brain stem.

3. Post-mortem appearance:
o External – There may be evidence of external injury on the scalp or fracture of
the skull. In addition to this there may be extravasations of blood.
o Internal –
 The brain and the meninges are congested.
 The right side of the heart is full and the left is usually empty.
 Lungs (both) are congested and oedematous.
Syncope:
Syncope is sudden cessation of the heart and failure of circulation leading to death.
Post-mortem appearance:
1) In cases of death due to anaemia, heart muscles are contracted and the chambers
are empty, and in cases of death due to asthenia, the chambers of the heart contain
blood.
2) Lungs, brain and abdominal organs are usually pale.
3) Capillary vessels are dilated due to reflex vasodilatation.
Asphyxia:
Asphyxia may be defined as a state in which the body lacks oxygen because of some
mechanical interference with the process of breathing.
The definition of asphyxia a extended to a state in which two elements are combined –
1) Hypoxia, being a condition in which there is an inadequate supply of oxygen to
the tissues, and
2) Hypercapnoea (hypercarbia), being an increase in the carbon dioxide tension in
the blood and tissues.
Post-mortem appearance:
o External –
 Post-mortem lividity (bluish color of the skin) is marked.
 Face is cyanosed (bluish discoloration).
 Tongue is protruded in most cases.
 Frothy (bubble like) and bloody mucus escapes from the mouth and
nostrils.
 Pupil (circular opening in the centre of the iris) – dilated.
 Tardieus spots (petechial haemorrhage) are frequently seen under the skin
all over the body or conjunctiva.
 There may be escape of faeces, or seminal fluid.

4. o Internal –
 The blood is dark and fluid.
 The right side of the heart is full whereas the left side is empty.
 The larynx and trachea are congested and contain a varying amount of
frothy mucus.
 Lungs-congested and oedematous.
 Taridieus spots may be seen under the mucous membrane of the various
organs.
 Other internal organs- more or less congested.

5. Reading aids
Medicological: relating to the legal aspects of the practice of medicine.
Transplantation: to transfer an organ or tissue from one part to another or from one
person or animal to another.
EEG: Electroencephalogram. EEG patterns reflect the state of the patient’s brain and
level of consciousness in a characteristic manner. Used in the diagnosis and management
of epilepsy and sleep disorder.
Electroencephalography: The technique for recording the electrical activity from different
parts of the brain and converting them into an EEG.
Encephalograph: apparatus for recording EEG.
ECG: Electrocardiogram. It is a recording of the electrical activity of the heart on a
moving paper strip.
Electrocardiograph: apparatus for recording ECG.
Encephalography: It can be used to diagnose heart disease.
Hypostasis: Accumulation of fluid or blood in a dependent part of the body, under the
influence of the gravity, in cases of poor circulation.
Fibrinolysis: The breakdown of fibrin in blood clot especially by enzymes.
Fibrin: a white insoluble elastic protein formed from fibrinogen when blood clots. It’s a
network that traps RBC and platelets.
Fibrinogen: a soluble protein in blood plasma.
Rigor mortis: The stiffness of joints and muscular rigidity of a dead body, caused by
depletion of ATP in the tissues. It begins 2-4 hours after death and lasts up to about 4
days, after which muscles and joints relax.
Adipocere: A wax like fatty substance formed during the decomposition of corpses
(grave wax).
Mummification: drying.

6. Meninges: Three connective tissue membranes which enclose brain and spinal cord
altogether are called meninges (dura mater, arachnoid mater and pia mater). CSF
circulates between them.
Oedema: Excessive accumulation of fluid in the tissues.
Protrusion- forward movement of lower jaw
Petechial haemorrhage: Small round flat dark spots caused by bleeding into the skin or
beneath the mucous membrane.
Larynx: cartilaginous and muscular hollow organ. It forms part of the air passage to the
lung. In higher vertebrates it contains the vocal cords.

7. Meninges: Three connective tissue membranes which enclose brain and spinal cord
altogether are called meninges (dura mater, arachnoid mater and pia mater). CSF
circulates between them.
Oedema: Excessive accumulation of fluid in the tissues.
Protrusion- forward movement of lower jaw
Petechial haemorrhage: Small round flat dark spots caused by bleeding into the skin or
beneath the mucous membrane.
Larynx: cartilaginous and muscular hollow organ. It forms part of the air passage to the
lung. In higher vertebrates it contains the vocal cords.