POST MORTEM CHANGES Signs of Death And Postmortem changes after death • Immediate Changes • Early Changes • Late Changes
Immediate changes • Permanent Cessation of Brain function • Complete Cessation of Circulatory function • Entire and permanent cessation of Respiratory function
Permanent Cessation of Brain function: • Loss of Sensations; viz, touch, pain and temperature • Loss of reflexes • Total loss of E.E.G. Rhythem • Confirmation of Brain- stem death
Brain –stem death: • The patient must be comatose state at least six hours. • No Abnormal Decorticate or decerebrate postures should be present • All brain-stem reflexes must be absent.
Pupils should be fixed • No Corneal reflex • Absent of the oculo-cepralic reflex • Absent vestibulo-ocular reflexes • No Motor responses • No Gag reflex • No Respiratory movements After disconnection of ventilator.
Complete Cessation of Circulatory Function • Magnus’s test • Finger nail test • Diaphanous test • Icard’s Fluorescein test • Heat test • Artery incision test • A flat E.C.G. for a continuous period of five minutes
Entire and permanent cessation of respiratory function • Mirror test • Feather test • Winslow’s glass water test.
Suspended Animation It is a condition in which the vital functions of the body are at such a low level that they cannot be appreciated by clinical examination Apparent death This may last few seconds to minutes. Voluntary- by yogis Involuntary – drowning, electrocution, heat stroke, typhoid fever etc.
Early Changes • Changes in the eye • Changes in the skin • Cooling of the body/Algor mortis • Post mortem lividity/Hypostasis • Rigor mortis/Cadaveric rigidity
Changes in the eye • Corneal Changes; • Loss of Clear Glistening • Dry, Cloudy and opaque • Loss of reflexes • Light reflex abolished • Intra Ocular tension falls, eye balls become flaccid and sink in the orbit • Blood flow in the retina becomes dotted and segmented look.
Optic disc looks pale. • Pupils fully dilated in the early stage and constict later due rigor mortis. • Brownish discolouration of the sclera due to cellular debris and dust Taches Noires
Changes in the Skin • Loss of its translucency • Pale and Ashy white appearance • Loss of Elasticity • Wounds will not gape if it is inflicted after death • Wounds caused during life will retain their characteristic features.
Cooling of the body • Imbalance between heat production and heat loss. • Loss of heat of body by means of conduction convection and radiation, till it balances with the temperature of surroundings. • Rate of cooling is fast during first few hours and later slows.
Temperature is recorded by Chemical thermometer- Thanotometer 25 cms. • Recording of temperature : Normal temp. – Rectal temp. Rate of temp. fall/hour • Variation of body temperature • Conditions in which heat may be retained or increased.
Sun stroke and pontine haemorrhage, disturbed heat regulating mechanism. • Tetanus and strychnine poisoning, due to increase in heat production in the muscle. • Acute bacterial or viral infection, lobar pneumonia, typhoid fever, encephalitis, etc. • Intense asphyxial conditions- rise of temp by 2-3 c at death “ Postmortem Caloricity”
The rate of cooling of the body is modified by the following conditions; • Age • Condition of the body • Mode of death • Surroundings • Environmental temperature
Postmortem Lividity It means discolouration or staining of the skin and organs after death due to accumulation of fluid blood in the dependent parts of the body. Post mortem staining/Hypostasis/Suggilation/ Vibices/ Livour mortis. 1- 3 hr. Starts 6-8 hr. Fixes.
Commencement of Lividity • Development of lividity • Fixation of lividity • Site of distribution • Pattern • Extent • Difference between lividity and bruise.
Medico-Legal Importance • It is a reliable sign of death • It gives the information about the position of the body at the time of death • Time since death can be estimated • Colour suggest the cause of death • Distribution of lividity may give the information about the manner of death
Changes in the Muscles • Primary relaxation/ Flaccidity • Rigor mortis/Cadaveric rigidity • Secondary relaxation
Primary relaxation Starts immediately after death with generalised relaxation of muscle tone: • Drop of lower Jaw • Eye balls lose their tension • Pupils are dilated • Joints are flabby • Smooth relaxation- incontinence of Urine and Faeces.
Rigor Mortis/ Cadaveric rigidity : This phenomenon comes immediately after the muscles have lost the power of contractility and is irreversible changes in the muscles of the body, both voluntary and involuntary. Myofibrils Myosin and Actin Adenosine Triphosphate – A.T.P.
Time of Onset : Temperate climates – 3-6 hours Tropical climates – 1-2 hours • Rigor mortis generally occurs when body is cold. • Not related to nerves action • Develops in paralysed limbs also • First appear in involuntary muscles • Last to be affected finger and toes muscles.
Duration : * Temperate climate – lasts for 2-3 days. • Tropical climate – 24 – 48 hours in winter 18 - 36 hours in summer • In general – 1-2 hours sets on for , 12 hours develops for - 12 hours maintaines and after 12 hours passes of
Circumstances modifying the Onset and Duration of Rigor mortis. Age- Rigor – Mortis is very rare in premature infants. Rigor –mortis is slow in adolescent and healthy adults Muscular conditon and activity before death. Onset is slow and duration is longer in muscular and healthy body at rest.
Manner of death : • In wasting disease and great exhaustion- cholera, plague, typhoid, T.B. Cancer etc. the onset is early and disappears soon. • In diseases – Pneumonia, asphyxia and nervous conditions- onset is delayed Atmospheric condtions: • In dry and cold air-onset slow and lost for long time. Warm and moist air onset is rapid and duration short.
Conditions Simulating Rigor-Mortis • Heat Stiffening • Cold Stiffening • Cadaveric Spasm Secondary Relaxation : • Muscles become soft and Flaccid • Do not respond to a mechnical and electrical stimulus.
Late Signs Of Death • Decomposition / Putrefaction. • Adipocere formation / Saponification. • Mummification.
Decomposition / Putrefaction • Last stage in the resolution of the body,from the organic to the inorganic state, is a certain sign of death. AUTOLYSIS • Rise of enzyme levels in the tissue cells after death. • Softening & liquefying of the body tissue. • Starts 3-4 hrs after death and continues for 2-3 days.
BACTERIAL ACTION • Action of bacterial enzymes on tissue components – carbohydrates/fat/proteins. • Bacterial growth – warmth,moisture are conditions favourable. • Clostridium welchii, streptococci, E coli, B proteus.
CHARACTERISTIC FEATURES COLOUR CHANGES • Greenish discoloration of skin over caecum and flanks after death appears 18-24 hrs. • Greenish to black discoloration- ‘Sulphmethahaemoglobin’ formed by H2S due to microorganisms in the large intestine. • Appears early in summer & delayed in winter.
Discoloration spreads- front of abdomen, external genitals, chest, neck, face, arms and legs – spreads whole body in 24-36 hrs. • Discoloration of vessel walls due to pigmentation from decomposed blood over the shoulder and groin. Arborescent pattern- ‘Marbling’
GASES OF PUTRIFACTION • Development of gases under the skin and hollow viscera 18-36 hrs. 24-48 hrs in solid viscera. • H2S, ammonia, phosphated hydrogen, CO2 and methane. • Causes pseudo rigidity, exerts pressure. • More gases accumulation, body floats in water.
PRESSURE EFFECTS OF PUTREFACTIVE GASES • Displaces the diaphragm upwards. • Discolored fluid and liquefied tissue mixes with gases producing froth. • Bloating of the features. • Shifting of the area of hypostasis. • Changes in skin, hair and wound. • Extrusion of fluid from the mouth and nose. • Emptying of the heart. • Changes in appearance of genitals.
APPEARANCE OF MAGGOTS • Flies lay eggs over the decomposed body- nose, mouth, vagina and anus in 18-36 hrs. • After 24-36 hrs eggs hatch into larvae or maggots, enter the body and destroy the tissues. • After 4-5 days develop into pupae. • After 7-8 days into adult fly.
OTHER SEQULAE • Fall of teeth • Separation of skull sutures • Liquefied brain matter oozes out. • ‘Colliquative putrifaction’ – this process takes place between 7-14 days.
INTERNALLY STOMACH • Dark red patches over the walls • Perforation due to autolysis LIVER • Softens and flabby • Becomes spongy ‘Foamy liver’
Early putrefaction 24-48hrs Larynx, trachea, brain of infants, stomach, intestines, spleen, omentum and mesentery, liver and adult brain. • Late putrefaction 2-3 weeks Heart, lungs, kidneys, bladder, esophagus, pancreas, diaphragm, blood vessels, prostate, testis and non gravid uterus, ovaries.
FACTORS MODIFYING PUTREFACTION • EXTERNAL Warmth and clothing • Putrefaction begins at 10°C and occurs rapidly at 37°C. • Freezing point – bacterial growth inhibited and putrefaction will not occur. • Clothing hastens putrefaction initially and protects against flies and insects.
Moisture • Help in rapid multiplication of organisms. • Bodies recovered from water if left in air, decomposes rapidly. Air • 1 week in air = 2 weeks in water = 8 weeks buried – ‘Casper dictum’
Manner of burial • In air tight coffins, very little change of body for long periods. • Without coffins, putrefaction is very rapid. • Bodies in deep graves putrefy very slow. • Bodies buried in lime, decomposition is retarded. • Bodies in sandy and porous soils are conducive to mummification.
INTERNAL FACTORS • Age and condition of the body • Sex • Mode of death
ADIPOCERE • Modification of the process of putrifaction in the dead body is (checked and is replaced) adipocere formation. • Hydrolisation of fatty tissue into fatty acids. • Bacterial fat splitting enzymes and moisture are essential – Lecithinase. • Composed of saturated fatty acids by palmitic, stearic, hydroxystearic, olic acids
Yellowish white, greasy wax with rancid smell. • It forms at any site where fatty tissue is present. • Time required, in summer-3 wks, in tropics-5 to 15 days. • M.L.I. – to establish the identity - cause of death - time since death - place of death
MUMMIFICATION • It is a peculiar desiccation of a dead body where by its soft parts shrivel up but retain the natural appearance and the features of the body. • Rusty brown color, dry, leathery skin adherent to bones. • Internal organs get transformed into a thick brown mass.
Mummification occurs in bodies buried in shallow graves, in dry sandy soils. • Time – 3 months to 1-2 yrs • M.L.I. – Identification - Cause of death - Time since death - Place of death
Time since death/ post mortem interval • Important clue for investigation of time. • It helps apprehend the person likely to be involved. • Point to be ascertained are; -cooling of the body -post mortem lividity -rigor mortis -decomposition changes
Contents of stomach and bowels • Contents of urinary bladder • Biochemical changes • Circumstantial evidence