Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Forensic medicine > PM changes and artefacts > Flashcards

PM changes and artefacts Flashcards

1
Q

what is algor mortis

A

cooling after death

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

which cells have the lowest resistance to hypoxia?

A

brain and spinal cord (4mins)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Which cells have the greatest resistance to hypoxia?

A

bone and corneas (48hrs)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

PM artefact that occurs following resuscitation attempt (incl. masks/intubation) against buccal mucosa are which type of injury?

A

mucosa of cheek against teeth = abrasion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Person who had MI in street and ambulance attempted CPR is found to have abrasions to face and a perforated stomach - explain this.

A

Abrasions from fall to ground

Stomach can tear when pressure applied during chest compressions, especially when stomach is full.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

bacteria favours which kind of putrefaction?

A

wet putrefaction is favoured by bacteria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Adipocere is favoured in dry conditions - true or false?

A

false
adipocere is favoured in wet conditions
mummification favoured in dry conditions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

A foetus lost to intra-uterine death will have which sign of putrefaction?

A

maceration of foetus due to sterile but wet environment of placenta.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

When determining the PMI, the rate method observes what?

A

Rate method observes/measures changes which occur at a known rate.
E.g. vitreous K+, rigor, cooling, putrefaction, lividity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What does the concurrence method use in determining PMI?

A

Events which occurred at known times e.g. watch which stopped by blow, digestion of meal, or CCTV footage.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

algor mortis is a good indicator of PMI after 24hrs - true or false

A

false

algor mortis is a good indicator of PMI in first 24hrs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What do you need to bear in mind when using cooling to determine PMI?

A

Should only be used in cool and temperate climates.
The body temperature at time of death is unknown and can be higher/lower depending on CoD.
The environmental temperature during cooling period has likely fluctuated.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Newton’s cooling curve shifts left when?

A

Curve shifts left in hypothermia, thin people, cool climates

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Newton’s cooling curve shifts right when?

A

Shifts right in hyperpyrexia, warm climate, heavy clothing,.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

The Henssge nomogram allows correction for…?

A

body weight, clothing, drafts, water

factors applied to body weight

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

When can Henssge nomogram NOT be used?

A 
Strong heat source nearby
Cooling source nearby
Underlying surface conducts away heat (metal table)
Abnormal body temp. at death
Body has been moved
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What does Henssge nomogram assume?

A

normal body temp at time of death and no change in cooling conditions.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are the stages of muscle flaccidity?

A
  1. Primary flaccidity
  2. Rigor mortis
  3. Secondary flaccidity
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Primary flaccidity is permanent - true or false

A

false
primary flaccidity = no tone
secondary flaccidity = permanent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

rigor is postponed in freezing - true or false

A

true

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Describe the muscle stiffening that occurs in hot temperatures.

A

accelerates rigor process

protein coagulation and shortening of muscles -> pugilistic posture

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

In life, formation of actin-myosin bridges stimulates muscle contraction. How is this affected in death?

A

Ca2+ still floods into cells and the actin-myosin bridges form however they cannot relax due to lack of ATP (required for breakdown) -> sustained contraction.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Fully formed rigor can be broken and re-form - true or false

A

false

fully formed rigor if ‘broken’ by force (undressing) will not reform

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Partially formed rigor will continue to form even if broken - true or false

A

true

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What factors effect the rate of rigor development?

A

onset/duration depend on:
environmental temperature
muscle activity prior to death

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Rapid onset of rigor is associated with shorter duration - true or false

A

true

Rapid onset of rigor is associated with short duration (will lessen faster)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

rigor develops in smallest muscles first then larger muscle groups affected next - true or false

A

FALSE
rigor develops simultaneously in all muscles
smaller muscles groups are COMPLETELY involved earlier vs. larger muscles and this passes off (putrefaction) in the same sequence

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

onset of rigor mortis is a useful indicator of PMI - true or false

A

false

onset of rigor is an unreliable indicator of PMI

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What is the average time until first appearance of rigor mortis?

A

first appearance on average 3hr pm

30
Q

Rigor is fully established on average by 8hrs PM, but what is the range in which this can occur?

A

fully established by 8hrs but range is 2-20hrs

31
Q

How long does rigor often last for?

A

24-36hrs

32
Q

Why does muscle activity or starvation prior to death hasten rigor?

A

glycogen stores are depleted

33
Q

What situations hasten rigor onset?

A

high environmental temp
muscle activity or starvation prior to death
septicaemia
children, elderly

34
Q

you need to be careful not to confuse intensity of rigor with…?

A

degree of development
e.g., stronger intensity of rigor in strong adult males vs. elderly woman but this does not mean it is further ahead in process

35
Q

stiffening that occurs at moment of death and persists into period of rigor mortis is known as ?

A

cadaveric spasm - rare, instantaneous form of rigor

36
Q

Rule of thumb: warm + flaccid =

A

warm + flaccid = dead <3hrs

37
Q

Rule of thumb: warm + stiff =

A

warm + stiff = dead 3-8hrs

38
Q

Rule of thumb: cold + stiff =

A

cold + stiff = dead 8-36hrs

39
Q

Rule of thumb: cold + flaccid =

A

cold + flaccid = dead >36hrs

40
Q

what is lividity?

A

the gravitational settling of liquid blood in capillaries - seen as purple discolouration in dependent areas

41
Q

punctate haemorrhage is seen in which type of lividity?

A

punctate haemorrhage within intense lividity

42
Q

what is lividity a good indicator of?

A

position of body since death

43
Q

When is lividity first noticeable and when is it well-formed?

A

red patches often within 30mins (up to 2hrs)

wellformed by 4hrs

44
Q

Lividity is at its maximum intensity when?

A

8-12hrs

45
Q

Lividity that no longer blanches tells you … ?

A

Lividity is fixed after 12hrs and no longer blanches

46
Q

Which patients have minimal lividity?

A

delayed or minimal lividity in anaemia or haemorrhage

47
Q

Fixation of lividity is absolute - true or false.

A

false

fixation is when lividity no longer blanches on pressure but it is relative, not absolute.

48
Q

Primary lividity pattern fades away on moving a body and a new secondary pattern forms - how long is the PMI?

A

Movement before 6hrs (before well-formed) -> fading of primary and onset of secondary pattern

49
Q

Primary lividity remains on moving a body but a new secondary pattern still forms - how long is PMI?

A

Movement after 10hrs (well-formed but not fully fixed)
Primary pattern fixed enough to remain but enough fluid blood to form a new secondary pattern -> dual distribution e.g., front and back

50
Q

Primary lividity pattern remains on movement of body, no secondary pattern forms - how long is PMI?

A

Movement after 24hrs (well-formed and fully fixed)

Not enough fluid blood to create secondary pattern

51
Q

what does contact pallor show in relation to lividity?

A

contact pallor shows areas of pressure between lividities

52
Q

within an area of lividity there are some burst blood vessels - what is this called?

A

punctate hypostasis = burst blood vessels within congested areas of lividity

53
Q

bright pink lividity is a sign of carbon monoxide poisoning - true or false

A

FALSE
bright pink: refrigeration, hypothermia
cherry pink: CO

54
Q

chocolate brown lividity is seen in which deaths?

A

methaemoglobin (chlorate) deaths

55
Q

cyanide poisoning causes scarlet lividity - true or false

A

true

56
Q

An MI can be confused with normal lividity of the heart - true or false

A

true

the lividity of the heart mimics an MI with the posterior surface congested and the front pale

57
Q

slow initial cooling delays onset of putrefaction - true or false

A

false

slow initial cooling e.g., due to clothing or bedding will hasten putrefaction

58
Q

Describe the process of putrefaction.

A 
Green discolouration in abdomen RIF 
Passage of rigor 
Marbling 
Skin blisters and slippage 
Gas production and bloating 
Loss of hair and nails, liquefaction
skeletonisation
59
Q

2 days into putrefaction process - what change is seen?

A

green discolouration starting in RIF of abdomen

60
Q

What causes the marbling sign in putrefaction?

A

blood vessels are mapped out by bacteria

61
Q

What part of putrefaction begins at 1 week?

A

gas production and bloating
methane, H2, H2S, NH3
Ptomains (putrescine, cadaverine) -> sniffer dogs!

62
Q

How long does skeletonisation take?

A

normally years

can occur in days if body is in warm environment with insects

63
Q

Which 2 organs will be softened and honeycombed by gas from internal putrefaction?

A

liver and brain are softened and honeycombed by gas

64
Q

Which organs are slow to putrefy?

A

uterus and prostate are slow to putrefy since more fibrous

65
Q

Internal putrefaction makes heart look …?

A

heart is dilated and flabby from internal putrefaction

66
Q

When can stomach contents be useful for PMI?

A

useful if time of last meal is known since food typically remains in stomach for up to 3-4hrs
NB. food can persist undigested for several day s following severe trauma (e.g. those in ITU)

67
Q

blue bottle and greenbottle flies are attracted by smell - true or false

A

true

68
Q

Which bacteria is important in the saponification process?

A

clostridium welchii

69
Q

The saponification process becomes visible after weeks/months. Where on the body might you see it?

A

cheeks, breasts, buttocks

70
Q

mummification is more common in adults vs. children - true or false

A

false
more common in infants vs. adults
partial mummification can occur in some adults during summer months (fingers and toes normally)

Forensic medicine (10 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions