Postmortem changes

Question 1

Recognise the diffculties in ascertaining the timing of death.

Answer 1

Rule of thumb:

• 1 degree is lost per hour
• If the body is found warm and floppy death occurred within 12 hours. If body is found cold and floppy then death has occurred past 24 hours.
• 0-12 hours change in body temperature is most important
• 24 hours: rigor mortis and hypostasis- rule of sixes- rigorous mortis visible after 6 hours- biological variability and the environment in which the body was left.
• 48 hours to 3 weeks putrefaction
• months to years: Adipocere, mummification, skeletisation

Stomach emptying: too many factors involved e.g. nature of food/rate of metabolism, medicines.

Toxilogical considerations

Question 2

List the main changes which occur to the body after death.

Answer 2

EARLY CHANGES
- Temperature decrease: when cells active they metabolise and produce energy. This energy releases heat and therefore keeps the body warm.
When cells die they can no longer produce heat. Descent and then slight increase due microorganisms in body producing heat
-Rigor Mortis: stiffening of muscles following death.
As a result of anaerobic metabolism- build up of metabolites and reduction in ATP. Contraction can be so severe as to break bones, cause haemorrhage in the brain. Detected in small muscles before large ones.
- Post-mortem hypostasis; Settling of blood vessels under the pressure of gravity due to contact with surfaces. Gives rise to areas of pressure pallor and lividity ( red areas). Blood vessels cannot open so blood cannot pass through it. Not so useful in determining time of death but can be useful in determining position of

LATER CHANGES

• skeletonisation: depends on soil moisture and organisms
• Mummification : dessication in warmth. inhibits putrefication
• Putrefication : microorganism degeneration. Factors: cleanliness of environment, humidity. After 2-3 days greenish discolouration. After 1 week blistering.
• Autolysis : enzymes inside the system degeneration
• Adipocere formation : Saponification- adipose tissue in ionic solution forms soap
• Maceration
• Embalming
• Post-mortem mutilation