explained in this presentation: Modes of death, thenatology, death, levels of death, coma, asphyxia, signs of death, ECG, EEG, syncope, rigormortis, algomortis, post-mortem lividity, flaccidity, putrefaction, mummification.

1. Death
Dr. Aamir Farooq
M. Phil. Pathology
dr.aamirfarooq@hotmail.com

2. Death
• Thanatology
• Cessation of all physiological processes or complete and permanent
cessation of circulation and respiration is called Death.

3. Levels of death
• Cellular:
Individual death of cells of tissues
• Somatic:
Individual animal death (irreversible cessation vital organs)

4. Modes of death
• Coma:
Cessation of function of brain
• Asphyxia:
Cessation of function of lungs
• Syncope:
Cessation of function of heart

5. Coma
• It is a state of unconsciousness from which the patient cannot be aroused, even
by powerful stimulation.
• failure of brain function
• Etiology
a) Traumatic injury to the brain.
b) Accidental collision of animal .with any object
c) Falling of animal from height.
d) Fighting with other animals.
e) May be caused by cerebral hemorrhages, thrombosis, embolism ,tumors
,abscesses and other inflammatory conditions of brain.
f) Intoxication with certain chemicals such as CO and barbiturates.
g) Presence of parasites such as Coenurus cerebralis

6. Asphyxia
• Death due to failure of function of lungs and may be due to lack of O2
in respired air resulting in hypoxia.
• Etiology:
a) Mechanical obstruction in the respiratory tract .e.g., tumor,
inflammation, choke, anaphylactic reactions.
b) Lungs disease or pulmonary circulatory disturbances.
c) Strangulation (closure of respiratory passages from external
pressure on neck)
d) Inhalation of irrespirable gases e.g. CO, SO2, H2S, NO.

7. Signs of Death
• Immediate signs (Postmortem changes)
• Early signs (Early hours postmortem changes) (12-24 hours)
• Late signs (Late postmortem changes) (after 24 hours)

8. Immediate Signs
A. Insensibility
• Don’t conclude death
• Vagal inhibition, drowning.
• Loss of EEG for continuous
5 minutes

9. Cont….
B. Cessation of Circulation
Auscultation….. 5 minutes
Absence of pulse in
arteries
ECG absence…. 5 minutes

10. Cont…..
• C. Cessation of Respiration
• Auscultation… Respiratory Sounds
• Movement of chest and abdomen sounds…5 minutes

11. Early Signs
• Cooling of body (Algormortis)
• Changes in eye and skin
• Postmortem lividity (livormortis )
• Primary flaccidity
• Rigormortis
• Secondary flaccidity

12. Cooling of Body
• More accurate in the first 24 hours after death
• Heat production stops…….loss…..conduction….convection…..radiation
• Factors
• Body own temperature
• Temperature of the environment
• Size of the animal, subcutaneous fat, fur coat.
• Exposed surface of the body, radiating heat to the environment.
• Movement and humidity of air
• Immersion in water

13. Cont...
• These temperature assessments are made on the basis of body core
temperature.
• After death, intra-abdominal temperature is directly measured for
assessment……per rectum or intrahepatic.
• Oral and axillary temperature should not be used.
• The normal rate of cooling is 1.5 degree 0F loss/ hour at 75 oF
environmental temperature.
• Take two readings in an hour to get rate of cooling.

14. Changes in eye and skin
• Soon after death, glistening
appearance of the eye is
lost.
• Cornea becomes dry, cloudy
and opaque.
• Corneal reflex loss.
• Change in skin colour is not
so profound in animals , but
elasticity is lost.

15. Post-mortem Lividity
• This refers to discoloration of
body due to gravitational
blood settling after the heat
stops.
• Within about 30 to 60 minutes
of death, the blood in
coagulable due to release of
fibrinolysin from small vessels
• This help us to determine the
position of the body after
death.

16. Cont…
• 20 to 30 minutes ……….dull red patches which deeper in intensity with
increasing time.
• Differentiation of lividity from bruising can be made by incising the
skin.
• Lividity becomes perceptible between half hour after death……well
developed in next 3 to 4 hours and attain its maximum between 8 to
12 hours of death.
• Typically lividity has purple or reddish purple coloration.

17. Primary Flaccidity
• In ordinary circumstances, muscles relax immediately after death.
• Muscles become flabby and joints become flexible.
• This condition persists for a few hours.
• During this, muscles react to electrical and mechanical stimuli.
• Pupil of eye responds to atropine and physostigmine.

18. Rigor Mortis
• Stiffening and contraction of all
voluntary and involuntary
muscles
• Rigor mortis appears in small
muscles of the eyelids, lower
jaw and neck,followed by
limbs, involving first the small
distal joints and then the large
proximal joints of
knees,elbow,shoulder and hips.

19. Rigor Mortis Mechanism
Mechanism
Anoxic Tissue
Anaerobic
Glycolysis
Lactic acid
production
Glycogen
Depletion
ATP Depletion
Actin-myosin
cross bridge
formation
No detaching
due to ATP
depletion

20. Cont…
• The gradual disappearance
of Rigor mortis is due to
suffer of coagulated
proteins by autolytic
fermentation

21. Factors
Temperature
Cold temperature Inhibits rigor
Slower onset and slower
progression of rigor
Warm temperature
Accelerates rigor Faster onset and faster progression
Activity before death
Anaerobic exercise
Accelerates rigor
Lack of oxygen to muscle, lactic
acid, and higher body temp
accelerates Rigor Mortis
Body weight
Thin
Accelerated rigor
Body loses oxygen quickly and body
heats faster
obese Slow rigor mortis Fat stores oxygen

22. Secondary flaccidity
• It is the relaxation of muscles with decline of rigor mortis.
• Rigor mortis passes of in some order in which it develops.
• All the body muscles become soft and flaccid.
• Muscles do not respond to electrical or mechanical stimuli.

23. Late Signs
• Putrefaction
• Adipocere
• Mummification

24. Putrefaction
• Putrefaction is post mortem
destruction of soft tissues of
the body by the action of
bacteria and endogenous
enzymes both.
a) Change in tissue
b) Change in color
c) development of gases
d) liquefaction

25. Cont...
• Environmental temperature has great influence on the rate of
development of putrefaction.
• Putrefaction is optimal at temperature ranging between 70-100oF (21-
38oC) and is retarded when temperature falls below 50oF (10oC).
• Greater humidity will increase putrefaction rate.
• Putrefaction starts from death and is completed in almost 1 week
after which there is soft and putrefied viscera and body muscles can
be seen.

26. Adipocere
• Saponification or adipocere is a modification of putrefaction
characterized by the formation of fatty tissue into yellowish, greasy,
wax-like substance, with a sweetish rancid odor.
• It is first developed in sub-cutaneous fat and rarely in visceral organs.
• It can be seen at 2-3 weeks after death.
• Warm, moist, anaerobic environment

27. Mummification
• Desiccation of tissue
• Leathery mass
tendons surrounding
the bones
• This condition is seen
in 3-4 weeks.

28. TIME SINCE DEATH CONDITION OF CARCASS
Less than 1hour Body is warm
2-3 hours Patchy lividity
6-8 hours Lividity fully developed and fixed
12 hours Rigor mortis present all over
24-36 hours Rigor mortis receding or absent. Abdomen
distended with gases.
48 hours Trunk or thoracic area bloated, swollen
discoloured face.
72 hours Body swollen and disfigured, hair loss, tissue soft
and discoloured .
1 week Soft and putrefied viscera.
2-3 weeks Only dehydrated viscera i.e. adipose week
3-4 weeks Mummification
5-6 weeks Only skeleton is present.
PROGRESSION OF CHANGES AFTER DEATH

29. Temperature of body Stiffness if body Time since death
Warm Not stiff Not dead more than 3 hrs
Warm
Stiff
Dead between 3 and 8 hrs
Cold
Stiff
Dead 8 to 72 hours
Cold Not stiff Dead more than 72 hours