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Flashcards in Postmortem Changes Deck (46)
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1

What is death

The irreversible failure of the cardiovascular system - but exceptions do occur

2

What happens after cardiovascular failure

Failure of oxygen delivery to the tissues resulting in cellular death

3

What happens after cellular death

Energy production ceases and the body cools

4

What happens after the body cools

Circulating blood becomes stagnant and settles under the effects of gravity.

5

What does the failure of the usual body defences cause

It will no longer be able to inhibit the proliferation of bacteria so putrefaction ensues

6

What can significantly affect the body

Post mortem predation by animals

7

When is the best opportunity for timing death

First 18 hours after death

8

What can cause inaccuracy

Inherent biological variability

9

What is the mainstay in the first 12 hours after death

Measurement of body temperature

10

What type of curve is produced in the rate of body cooling

Sigmoid

11

What can influence the rate of body cooling

Body temp at time of death (usual temp?)
Is the body clothed (nature of clothing?)
Natural insulation of the body
Convection currents
Environmental temperature
The length of the plateau phase of the cooling curve

12

What is the time range in time of death calculations under the most favourable conditions

+/- 2.5 hours

13

How many degrees does the body cool per hour (rule of thumb)

1oC

14

Can the rate at which the stomach empties be used as a means of measuring the time of death or the time since the last meal?

No
As too many factors influence the rate at which the stomach empties
But it can offer information on what the deceased last ate depending on the condition of the material remaining

15

What can influence the rate at which the stomach empties

Nature/amount of food
Solids vs liquids
Stress
Certain medication

16

What is rigor mortis

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

17

Why does rigor mortis occur

Due to the reduction of ATP within the muscles after death
All muscle fibres are affected
Theoretically detected in smaller muscles before larger muscles

18

When does rigor become apparent

5-7 hours after death
Fully established 8-12 hours after death

19

When does rigor dissipate

Dissipates in line with ensuing decomposition and frequently absent by 36 hours after death (body returns to a flaccid state)

20

What is the problem with using rigor mortis in timing death

Biological variability

21

When can rigor mortis potentially be used

First couple of days after death

22

What can affect the development of rigor

Ambient temperature
Cadaveric Spasm (grasping of objects)

23

What other methods have been investigated in estimating the time of death

Measurement of the level of potassium ions in the vitreous humour of the eye

24

What causes decomposition and putrefaction

The action of bacterial micro-organisms
Process begins at death, but takes a period of time to become detectable

25

What variables needs to be considered in regards to decomposition and putrefaction

Ambient temperature
Humidity
“Cleanliness” of the environment in which the body lies

26

What colour appears after 2-3 days in abdominal skin

Greenish discolouration

27

What occurs 1 week after death

Blister formation and tissue swelling, including gas formation in body cavities

28

Why can vascular marbling be seen

Due to putrefaction of the superficial veins in the skin

29

What can be resistant to putrefaction

Certain organs
their persistence can be valuable for identification purposes

30

What is mummification

Process of “dry” decomposition, with desiccation of the body and a relative lack of bacterial involvement so Body essentially “dries out”; the facial features and hands/feet may become rigid