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Flashcards in Post mortem changes Deck (63)

before death

ante mortem


moment of death

agonal period or peri mortem


after death

post mortem


What are the three questions that should be answered in an autopsy?

  • time of death?
  • cause of death?
  • maner of death?


Name four types of death?

  • cellular death
  • somatic death
  • clinical death
  • "apparent death" suspended animation


What is cellular death?

  • due to lack of oxygen and blood
  • cells don't longer
    • function
    • have metabolic activity
    • aerobic respiration
  • different tissues die at different rates


When do different tissues die?

  • cerebral cortex/neurons: within minutes
  • white blood cells: within hours
  • connective tissue and muscle cells: within days


What is somatic death?

  • the body loses its sentinent personality, i.e. doesn't perceive or feel
  • unconscious
  • reflex activity is intact
  • cardiorespiratory function is intact


What is clinical death?

permanent cessation of cardiovascular, respiratory and brain functions


Name early changes occuring with death


  • loss of all reflexes
  • no reaction to painful stimuli
  • muscular flaccidity, complete loss of tone
  • cessation of heart beat (cardiac death/arrest) and respiratory movements
  • eye signs: loss of corneal and light reflexes, fixed dilated pupils, eyelids usually closed incompletely
  • pallor mortis, 15-120 minutes after death


Name some post mortal processes


  • no glucose and oxygen --> ATP is consumed
  • cellular homeostasis cease
  • autlysis by cellular enzymes
  • bacteria spread from the bowl
  • insects and animals scavenger


Name some chemical changes occuring with death


  • glucose is consumed rapidly --> produces lactate
  • potassium leaks from the cell
  • enzymes and bacteria denature proteins
  • fat: solid to fluid
  • DNA is stable for a long time


Due to which conditions occurs a state that may mimic death?


  • head injury
  • hypothermia
  • sun or heat stroke
  • drowning
  • drug overdose
  • electrocution


Name five early signs of death

  • changes in the eye
  • changes in the skin, pallor mortis
  • livor mortis (post mortem lividity/hypostasis)
  • rigor mortis (cadaveric rigidity)
  • allgor mortis (cooling of the body)


What are the three classical signs for certain death?

  • livor
  • rigor
  • algor


Name changes in the eye occuring with death

  • corneal changes
    • loss of clear glistening
    • dry, cloudy and opaque
    • loss of reflexes
  • intraocular tension falls, eye balls become flaccid and sink in the orbit
  • pupils fully dilated in the early stage and constrict later due to rigor mortis
  • brownish discolouration of the sclera due to cellular debris and dust


Name changes in the skin occuring with death

  • loss of translucency
  • pale and ashy white appearance - pallor mortis
  • loss of elasticity


Livor mortis facts

  • gravity moves blood after circulation stopps
  • blood accumulates in the capillaries --> purple or reddish purple
  • in pressure areas --> pale
  • apparent after 0,5-1 hour
  • fixed after approx 8 hours
  • may not appear at all especially in infants, elderly, and anemic persons


Colour of hypostasis/livor mortis that indicates mode of death


carbon monoxide poisoning


Colour of hypostasis/livor mortis that indicates mode of death

dark blue-scarlet

cyanide poisoning


Colour of hypostasis/livor mortis that indicates mode of death




Colour of hypostasis/livor mortis that indicates mode of death


septic abortion caused by clostridium perfringes


Colour of hypostasis/livor mortis that indicates mode of death


anemia, hemorrhage


Colour of hypostasis/livor mortis that indicates mode of death

pink around large joints



Differences in livor mortis and contusion in respect to:

  • borders
  • colour
  • blanching
  • hemorrhage

  • borders:
    • livor: diffuse
    • contusions: distinct
  • colour:
    • livor: purple to red
    • contusion: purple to blue
  • blanching:
    • livor: present with fingure pressure
    • contusion: not present
  • hemorrhage:
    • livor: none
    • contusion: in soft tissue


what are vibices

post morte eccymoses, death spots (subcutaneous spots of bleedings)

  • limited to area of livor mortis
  • only occurs post mortem
  • due to increase in intravascular pressure that leads to mechanic rupture of subcutaneous capillaries and smaller vessels


What are petechial hemorrhages?

  • rupture of capillaries due to hydrostatic pressure that causes small areas of skin hemorrhaging
  • dark, circular spots ranging in size from pin-point to max 3mm
  • in the sclera of the eye and the face suggest asphyxation (suffocation, strangulation)


What is the forensic importance of hypostasis/livor mortis?


  • reliable sign of death
  • colour may suggest the cause of death
  • time since death can be estimated
  • it gives information about the position of the body at the time of death
  • indicates if the body was moved or not after death and could give information about the manner of death


Name post mortem changes in the muscle

  • primary relaxation/flaccidity
  • rigor mortis (cadaveric rigidity)
  • secondary relaxation


Name characteristics of primary relaxation


Starts immediately after death

  • drop of lower jaw
  • eye balls lose their tension
  • pupils are dilated
  • joints are flaccid
  • smooth muscle cells relaxation --> incontinence of urine and faeces


What are the chemical changes underlying rigor mortis?

  • death
  • cessation of respiration
  • depletion of oxygen used in the making of ATP
  • ATP no longer provided to operate the SERCA pumps in the membrane of the SR, which pump calcium ions into the termincal cisternae
  • calcium ions diffuse from the terminal cisternae and extracellular fluid to the sarcomere
  • Ca binds with troponin
  • cross bridging between myosin and actin proteins


Name three causes of rigor mortis

  • ATP depetion
  • actin-myosin interaction
  • lactic acid accumulation


Estimated time of death from rigor mortis

in face

1-4 hours


Estimated time of death from rigor mortis


4-6 hours


Estimated time of death from rigor mortis

increase in strenght for the next ....

6-12 hours


Estimated time of death from rigor mortis

re-establishment possible



Estimated time of death from rigor mortis

complete rigor

10-12 hours (2-20)


Estimated time of death from rigor mortis

decomposition starts --> secondary flaccidity

24-72 hours


Name three factors that affect the timing of rigor mortis

  • muscular activity before death
  • environmental temperature
  • age


How does muscular activity before death affect rigor mortis?

  • healthy and robust muscle at rest --> slow onset, duration longer
  • muscles exhausted/fatigued --> onset rapid, especially in those limbs being used
  • increased activity (convulsions, electrocution, lightning) --> rapid onset and short duration


How does environmental temperature affect rigor mortis?

  • cold and dry air --> onset slow, duration longer
  • warm and moist air --> onset fast, duration shorter


How does age affect rigor mortis?

  • infants and elderly --> rapid onset


Conditions mistaken for rigor mortis


  • heat stiffness
  • cold stiffness
  • cadaveric spasm / instantaneous rigor


Forensic implications of rigor mortis

  • reliable sign of death
  • time since death can roughly b estimated
  • indicates body position at death


What is the rate of body cooling in algor mortis?

1 degree C per hour during the first 24 hours


Times until a naked body reaches ambient temperature

  • a normal sized body
  • a thin body
  • an obese body

  • approx 28-30 hours
  • approx 20 hours
  • apporx 40-50 hours


Name five factors that affect the rate of cooling

  • conditions in which heat may be retained or increased
  • surface area of the body
  • environmental temperature
  • water
  • clothing, coverings and posture


How do conditions in which heat may be retained or increased affect the cooling rate of the body?

  • sun or heat stroke and pontine (brain stem) hemorrhage disturbe the heat regulating mechanism
  • tetanus and strychnine poisoning, due to increase in heat production in the muscle
  • if there is a fulminating infection, the body temperature may continue to rise for some hours after death


How does the surface area afffect the rate of cooling of the body?

larger surface area --> speeds up cooling rate


How does the environmental condition affect the cooling rate of the body?

  • higher humidity: rapid cooling rate
  • rapid air velocity: rapid cooling rate


How does water affect the cooling rate?

rapid cooling rate, more rapid in flowing water than still water


Rules of thumb for post mortem interval

  • warm and flaccid body
  • warm and stiff body
  • cold and stiff body
  • cold and flaccid body

  • < 3 hours
  • 3-8 hours
  • 8-36 hours
  • >36 hours


Name some late signs of death


  • decomposition/putrefaction (decay)
  • adipocere formation
  • mummification
  • putrid dry remains
  • skeletonisation


What is post mortem decomposition

Turning the tissue of the body into fluids and gases by the effect of bacteria and enzymes


Name two mechanisms leading to decay

  • autolysis: occurs by digestive enzymes released from the cells after death
  • putrefaction: bacterial action (Clostridium welchii, Streptococci, E coli, B proteus)
    • most common route of decomposition


Name morphological changes of putrefaction

  • green discolouration; 2 days
  • marbling of skin; 3-5 days
  • skin blisters, skin slippage (epidermolysis); 5-7 days
  • gas formation, swelling of body; 7-10 days


What does the speed of decomposition depend on?

  • amount of bacteria in the body
  • temperature (heat --> rapid)
  • humidity (high --> rapid)
  • injuries to body surface (promote putrefaction)


What influences the microbial, insect and animal activity on the dead body?

  • geographical location
  • time of year
  • exposure to sunlight
  • wrapping and confinement
  • burial (type of soil, burial dept)
  • haning above ground
  • burial under water
  • wounds
  • infections
  • burning
  • chemical treatment


Forensic importance of mummification


  • identification, could retain natural appearance and features of the body
  • time since death can roughly be estimated
  • can detect abnormal pathology inside deep organs


what are the chemical causes for adipocere and what are the optimal conditions for the formation of adipocere?

  • chemical causes:
    • hydrolysis
    • hydrogenation
  • conditions
    • moisture
    • warm environment


Forensic importance of adipocere (3)

  • preserve the body which can permit identification after death
  • it may give conclusions about the cause of death
  • it indicates that the time since death was at least weeks to several months


What are putrid dry remains?

  • the body continues to lose more soft tissue, and the process of skeletonisation begins
  • bones, tendons, hair and fingernails remain
  • still smell of decay


Forensic importance of skeletonisation

  • identification
  • may give conclusions about age, sex and stature
  • estimating time since death (e.g. carbon-14 dating)