28. The Body After Death Flashcards
What factors help estimate the time of death?
Changes in the body
Environmental evidence
Anamnesic evidence
What is the best method of estimating the time of death?
Core body temperature
What steps must you undergo before pronouncing death?
Pupillary light reflex Absence of breath Absence of heart sounds Absence of pulse Each checked for 1 min
What immediate changes happen after death?
No BP or oxygen
Loss of neuronal activity
Breathing stops
Small muscle twitches
What are the early changes after death?
Rigor mortis
Livor mortis
Algor mortis
What is the chemical process that causes rigor mortis?
Anaerobic metabolism in muscle leads to high lactic acid
irreversible actin and myosin binding lead to muscle rigidity
Which muscles does rigor mortis usually start in?
jaw, face, neck
What does the rate of onset of rigor mortis depend on?
Temperature (faster if warm) Physical activity before death Age Sex Build (faster in more muscle) Condition (faster in sepsis)
Give examples of how rigor mortis also affects organs
Causes myocardial contraction
Iris contraction can cause unequal pupils
Goose flesh
What is the time of death estimation if the body is warm and flaccid?
<3 hours
What is the time of death estimation if the body is warm and stiff?
2-8 hours
What is the time of death estimation if the body is cold and stiff?
8-36 hours
What is the time of death estimation if the body is cold and flaccid?
> 36 hours
What is cadaveric spasm?
Rare form of instantaneous rigor
Happens when person dies in the middle of intense physical or emotional activity
What are 2 more names for livor mortis?
Lividity
Hypostasis
What is livor mortis?
Gravity causes pooling of blood in veins and capillaries
Pink/purple/blue discoloration
No pooling in areas that were in contact with underlying surfaces
What is livor mortis useful for?
Can indicate if the body was moved after death
What can petechiae indicate?
Asphyxiation
What does cherry pink lividity indicate?
CO poisoning
What does pink lividity indicate?
Hypothermia
What does brick red lividity indicate?
Cyanide poisoning
What does bronze lividity indicate?
Clostridia perfringens sepsis
What is algor mortis?
The cooling of the body after death
Core temp falls by about 1C every hour after 3.5 hours
What is Newton’s law of cooling?
Warm body in a cool environment will lose heat from its surface until temperature equilibrilates
How is heat lost from the body after death?
Radiation
Convection
Conduction
Evaporation if wet
What graph is used to estimate time of death from body temperature?
Henssge’s temperature curve
How does the body decompose?
Autolysis of cells by their own enzymes
Soft tissues broken down by bacteria
What day does decomposition become visible?
3
What organs are the first to decompose?
Adrenal medulla
Pancreas
Which organs are the most resistant to decomposition?
Heart
Prostate
Uterus
What is putrefaction?
Liquefaction of tissue by bacteria
What is the green discoloration of the abdomen after death caused by?
Bacteria from the bowel break down haemoglobin
Where does putrefaction start?
RIF
Spreads to flanks
What effects does putrefaction have on the body?
Green discoloration of abdomen
Blister formation leading to ‘skin slipping’
Marbling of veins
Gas formation
What does gas formation in putrefaction lead to?
Bloating of the abdomen and scrotum
Purging of urine, faeces and gastric contents
What is Casper’s rule?
The body will take twice as long to decompose in water than on land
What is adipocere?
Hydrolysis and hydrogenation of adipose
Forms a waxy white substance which turns chalky over time
Why can adipocere be useful?
In damp conditions it can be useful to retain the shape of the face, body and injuries
What is mummification?
Drying of tissues instead of liquefactive putrefaction
What effect does mummification have on the body?
Skin becomes brown and leathery
Possible preservation of internal organs
What types of bodies are most likely to become mummified?
Thin people
Newborns
What is skeletonisation?
Loss of soft tissue
What is entomology?
Study of interaction of insects with the corpse to discover the time of death
