Post Mortem Changes in Forensic Medicine.new.pptx

Thanatology

1. Post Mortem Changes Dr. Satrajit Roy Department FSM Medical College, Kolkata

2. Changes after death Immediate Changes Early Changes Late Changes

3. Immediate Changes Permanent Cessation of Brain function leading to insensibility and loss of voluntary power Complete Cessation of Circulatory function. Entire and permanent cessation of Respiratory function.

4. Immediate Changes Permanent Cessation of Brain function : No sense. Loss of reflexes. No response. No tonicity of muscles. Complete Cessation of Circulatory function: Pulse, auscultation of heart sounds, ECG Diaphanous test, Magnus’s test, Icard’s test, Pressure test, Heat test, Cut test…..HISTORICAL IMPORTANCE Complete cessation of Respiratory function: Inspection, Palpation, Auscultation Feather test, Mirror’s Test, Winslow test …..HISTORICAL IMPORTANCE

5. Early Changes Changes in the skin Changes in the eye Algor mortis Livor mortis Rigor mortis

6. Early changes: Changes in Skin Loss of Elasticity Loss of its translucency Pale and Ashy white appearance

7. Early changes: Changes in Eyes Corneal changes Opacity of Cornea Shape of pupil Loss of ocular tension Taches noire Scleroitique Retinal Changes

8. Algor Mortis: Cooling of dead body 1 st medico legal use of recoding of body temperature made by Dowler in 1950 for confirmation of death. At present, recoding of temperature of the dead bodies is done, the purpose being ‘estimation of time of death’. Heat loss from the body : conduction /convection /radiation / evaporation Rate of fall 0.75°F/h-1.5°F/h Sites to take temperature from

9. Algor Mortis: Factors influencing cooling Atmospheric temp Media of disposal of dead body. Body weight. Sex Age Clothing and coverings Air movements Dry weather. Position and posture of the dead body. Post mortem caloricity

10. Livor Mortis Synonyms: Post mortem Lividity/ Post mortem staining /Hypostasis / Suggilation / Vibices Bluish-purple or purplish-red discolouration which appears after death on the most dependant parts of the skin due to collection of blood in the capillaries and small veins (rete mucosum ) of the most superficial layers of the dermis due to gravity .

11. Livor Mortis: Formation & Theories In undisturbed position of the dead body, starts appearing in small patches on the dependent parts by the end of one hour. Gradually small patches increase in size and coalesce with each other and completion of spreading takes 5-6 hours. If undisturbed the position staining gets fixed and for that it takes another 5-6 hours.

12. Livor Mortis:Features Occurs externally on the dependent part, also occurs on the dependant parts of internal organs. Becomes discolored when decomposition started. It is an intra vascular phenomenon and no extravasations of blood. Contact pallor. Post mortem staining in drowning cases..

13. Livor Mortis: Colour in some poisoning Bright pink- hypothermia Bluish green- H2S Bluish violet- asphyxia Bright red- HCN, Burns Cherry red- CO Chocolate- Aniline, chlorates, bromates, nitrites Dark brown/yellow-Phosphorus

14. Livor Mortis: Medico-legal importance Sign of death Time passed since death Cause of death Position of the body Movement of the body Vs Bruise

15. Changes in the muscles Primary relaxation/ Flaccidity Rigor mortis/Cadaveric rigidity Secondary relaxation

16. Primary Relaxation Starts immediately after death with generalized relaxation of muscle tone: Drop of lower Jaw Eye balls lose their tension Joints are flabby Smooth muscle relaxation- incontinence of Urine and feces . C ontinue for around an hour after death. After lapse of this period, the muscles of the body gradually becomes stiff or rigid and it indicates Molecular death of muscles.

17. Rigor Mortis Rigor Mortis is that state of muscles of the dead body when they become stiff or rigid with some degree of shortening. Mechanism Order of appearance Demonstration of rigor mortis Duration Factors influencing formation and stay of rigor mortis

18. Conditions mimicking Rigor Mortis Cadaveric spam Heat stiffening Cold Stiffening Gas stiffening

19. Cadaveric spasm Cataleptic rigidity, instantaneous rigidity/rigor, postmortem spasm is a condition where the muscles that were in contraction at the moment of death, remain in contraction after death without passing through the stage of primary relaxation. Predisposing factors Last action Mechanism Cannot be simulated Disappearance

20. Heat Stiffening If death occurs due to second or third degree of burn injuries or the dead body is exposed to a temperature above 65 degree centigrade, heat stiffening occurs due to coagulation of muscle protein---- body becomes stiff. Flexor muscles take upper hand giving rise to a condition which is known as Pugilistic/ Boxer’s or Fencing attitude of the body.

21. Cold Stiffening This occurs when body remains in extreme cold atmosphere for a reasonable period due to fridging of the body fluids at the tissue level and in the synovial sacs of the joints and hardening of subcutaneous fatty tissue.

22. Gas Stiffening During the stage of decomposition, when the cause of stiffening is very obvious from the discoloration, swelling and foul smell.

23. Secondary relaxation Alkali on muscle Acid on myosin Autodigestion

24. Late changes after death Decomposition : Autolysis and Putrefaction Adipocere Formation / Saponification Mummification

25. Autolysis It is the breakdown of cells and organs through an aseptic chemical process caused by intracellular enzymes . Accelerated by heat and slowed by cold. Occurs first in pancreas. Dead foetus in utero – MACERATION. Gastric mucosa may show autolysis even in living in cases of head injury etc

26. Putrefaction It is a process by which the complex organic body tissues breakdown to simpler inorganic compounds or elements, due to the action of fermentation produced by saprophytic micro-organisms. There is decomposition of body proteins by anaerobic microorganism-----leading to production of ptoamines ( Putrescine & Cadaverine —have putrid odour ). Gases produced during decomposition are hydrogen sulphide , carbon di oxide, carbon mono oxide, ammonia, marcaptans etc

27. Microorganisms involved Anaerobic spore forming bacilli. Coliform organism. Micrococci. Cl. Welchii , B.Coli , Staphylococcus, Non hemolytic Streptococcus, Diptheroids and Proteus are important ones. Some of these are natural inhabitants of GI & Respiratory tract. Increase in hydrogen ion and rapid decrease of oxygen favors growth of anaerobic organisms.

28. External signs of putrefaction Colour changes Gas formation Liquefaction FIRST EXTERNAL SIGN: GREENISH DISCOLOURATION occurs over right iliac fossa. [Summer – about 12 hours, Winter – 36 to 48 hours]

29. Marbling Invasion of blood vessels by organisms and production of H2S gas and formation of Sulphmethaemoglobin , causes greenish brown staining of the inner walls of the vessels. This makes the superficial veins prominent producing a marbled appearance of the skin of the area. Marbling becomes prominent in 36 to 48 hours in summer.

30. Gas formation 12 to 24 hours: Abdomen tensed due to gas accumulation, blood tinged froth from mouth, natural orifices 24 to 48 hours: Subcutaneous tissue emphysematous, bloated, breasts in female, scrotum and penis in males are swollen, tongue protrusion, denudation of cuticle due to blister rupture 48 to 72 hours: Prolapse of uterus (including gravid) and anus, eyeballs protrude, face is extremely swollen, discolored, subject is not identifiable from face and hairs and nails become loose and may be taken out easily.

31. Gas formation Between 3 to 5 days: Abdomen bursts, teeth becomes loose, swelling decreases due to escape of gases, skull separates in case of infants with liquefaction of brain Between 5 to 10 days: Liquefaction occurs, soft firm tissues change to thick semisolid black mass , decomposition starts in cartilages and ligaments

32. Others.. Skin slippage Sutural separation Crepitant soft tissues Loosening of appendages(H3N4T5) Postmortem luminescence( P.fischerii , A.mellea ) Fissures, splits and dehiscence

33. Skeletonization: Time required Factors affecting rate of skeletonization In air In water Buried bodies Without coffins(shallow vs deep grave) With coffins Mass burials Skeletonization v/s mummification

34. Internal changes due to decomposition Larynx and trachea:- 12-24 hrs; brownish red-greenish-softened Liver:- soft and flabby>multiple blisters> honeycomb liver Brain:- soft and pulpy> grayish fluid Stomach and intestines, spleen, heart, lungs, kidneys Diaphragm: putrifies late(?strength of muscular and aponeurotic structures) Prostrate, uterus

35. Factors influencing decomposition EXTERNAL FACTORS Temperature Moisture/recovered from water Air Clothing 5. Place of burial B . INTERNAL FACTORS Age Sex Condition of the body Cause of death Mutilated body parts

36. Delay putrefaction: Carbolic acid Heavy metal Strychnine Zinc chloride Resist putrefaction: Barbiturates Corrosives Cyanide Dhatura OP Strychnine Destroyed by putrefaction: Aconitine Morphine Succinylcholine Appear due to putrefaction: Alcohol Cyanide CO Hasten putrefaction: H2S Strychnine

37. Casper’s Dictum The time taken for the same amount of putrefaction to occur when the body is in air, water and buried earth is in the ratio of 1:2:8.

38. Adipocere formation Modified form of putrefaction in which a friable, crumbly, water insoluble greyish white to brown wax like material is produced in the dead body by the breakdown and conversion of body fats to fatty acids, mainly oleic, palmitic and stearic acids.

39. Mummification Modification of putrefaction in which the skin becomes brittle, contracted, dried, firm, leathery tough, parchment like, shrunken and wrinkled, turning yellow-brown to black in colour.

40. Estimation of post mortem interval By analysing immediate, early and late changes after death By analysing food in the stomach By state of urinary bladder Post-mortem chemistry/ Thanatochemistry Entomology of cadaver Scene of death

41. Thanatochemistry BLOOD: Carbohydrates, Lactic acid, Nitrogenous compounds, other organic compounds, electrolytes, enzymes CSF Vitreous Pericardial fluid Synovial fluid

42. Entomology of cadavers Usually 3 types of flies namely Common house fly , Green Bottle fly , Blue Bottle fly. Green and Blue bottle flies deposit or lay eggs over moist areas of dead body or nearby. Lays eggs within minutes. 1 st instar larva hatches from eggs within 8 hours 2 nd instar within next 24 hours, 2 nd to 3 rd instar within next 24 hours. 3 rd instar to pupa within next 3 days. Pupa to adults in next 5 days.

43. Presumption of survivorship (S.107 IEA) When the question is whether a man is alive or dead, and it is shown that he was alive within THIRTY years, the burden of proving that he is dead is on the person who affirms it. Presumption of Death (S.108 IEA) When the question is whether a man is alive or dead and it is proved that he has not been heard of for seven years by those who would naturally have heard of him if he had been alive, the burden of proving that he is alive is shifted to the person who affirms it.

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