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Flashcards in Postmortem Changes Deck (23):
1

Death

the irreversible failure of the CV system

2

What happens after death?

-failure of O2 delivery to the tissues resulting in cellular death
-energy production ceases and the body cools
- circulating blood becomes stagnant and settles under the effects of gravity
-the usual body defences fail and it can no longer inhibit the proliferation of bacteria- putrefaction ensues

3

How long after death is body temperature relevant?

up to 12 hours

4

What factors influence the rate of body cooling?

-clothes?
-nature of clothing
-usual temp
-natural insulation of body
-convection currents
-environmental temp
-length of plateau of cooling curve

5

What is the rule of thumb when it comes to body cooling?

1 degree per hour

6

How accurate can body temp be in time of death?

no better than +/- 2.5 hours

7

Why can the rate at which the stomach empties not be used as an indication of TOD?

Too many influencing factors:
-nature/amount of food
-solids vs liquids
-stress
-certain medication

8

What is rigor mortis?

stiffening and shortening of muscle fibres leading to rigidity of the musculature and fixation of the joints

9

What causes rigor mortis?

the reduction of ATP within the muscles after death

10

Describe the timeline of rigor mortis

-becomes apparent 5-7 hours after death
-usually fully established 8-12 hours after death
-dissipates in line with ensuing decomposition and frequently absent by 36 hours after death

11

What will affect the development of rigor?

ambient temperature

12

What causes putrefaction?

the action of bacterial micro-organisms; process begins at death but takes a period of time to become detectable

13

What variables should be considered with putrefaction?

-ambient temp
-humidity
-cleanliness of the environment

14

Describe the timeline of putrefaction

-2-3 day: greenish discolouration of the abdominal skin
-1 week: blister formation and tissue swelling, including gas formation in body cavities, Vascular marbling can be seen

15

Mummification

-a process of fry decomposition with desiccation of the body and a relative lack of bacterial involvement.
-body essentially dries out the facial features and hands/feet may become rigid

16

What induces adipocere formation?

the alteration of fatty tissue within the body into a greasy/waxy or brittle material which frequently remains attached to the bony skeleton and may retain the body structure to some extent. tends to occur in wet environments

17

What variables exist in skeletonisation?

exposure to meat eating animals and to dipterous larvae

18

Post mortem hypostasis/PM lividity/PM staining

represents the pooling of stagnant blood in dependent regions of the body under the influence of gravity

19

Describe the timeline of PM hypostasis.

begins as soon as the circulation of blood ceases but takes time to become visible usually about 1-2 hours and fully established by 6-12 hours

20

What is pressure pallor?

where the body surface has pressure applied there will be compression of the blood vessel preventing ingress of blood

21

What can the colour of hypostasis tell us?

-pink/purple= normal
-cherry red= carbon monoxide poisoning
-red/brown=methaemoglobin

22

PM artefacts

alteration or damage to body occurring after death which may mimic genuine processes occurring in life

23

What are examples of PM artefact?

-CPR
-animal predation
-traumatic injury