Brainscape's Knowledge GenomeTM

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


See full index

principles of disease > injury to the body and post mortem changes week 10 > Flashcards

injury to the body and post mortem changes week 10 Flashcards

1
Q

what are the three injury classifications

A
  • Sharp force
  • blunt force
  • ballistic
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what kind of injuries are sharp force

A
  • stabs

- incisions

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

what kind of injuries are blunt force

A
  • abrasions
  • bruises
  • lacerations
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what kind of injuries are ballistic

A
  • explosions

- gunshots (rifle/shotgun)

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

what is an abrasion

A
  • blunt force
  • superficial injury to the epidermis
  • crushing by vertical force (imprint)
  • scraping by tangenital force (graze over broad surface e.g. road rash)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what is a contusion

A

bruise

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

what is a bruise

A
  • blunt force

- crushing of the dermal blood vessels by mechanical impact causing leakage of blood from vessels into skin

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

what are the different types of presentations of bruises

A
  • bruising of internal organs
  • ‘tram-track’ bruising via rod, baton or plank-like object
  • clustered discoid bruises via fingertip pressure
  • black eyes via direct trauma or skull fractures
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

can you accurately age a bruise

A

no

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

what are lacerations caused by

A
  • impact against a flat surface (scalp or facial laceration)
  • impact by an edged or pointed object (brick, furniture corner, etc.)
  • rotation of tissue on limb/torso (flaying injury), caused by revolving wheel/machinery
  • excess frictional or tearing forces (senile skin tears, scalping)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what are incised wounds

A
  • sharp force
  • superficial sharp force injury caused by slashing motion
  • injury is longer on the skin surface than it is deep
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what are the features of lacerations

A
  • caused by blunt force
  • ragged margins
  • marginal abrasion
  • associated bruising
  • tissue bridging
  • slight bleeding
  • trace evidence
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what are the features of incisions

A
  • caused by sharp force
  • clean margins
  • no associated abrasion
  • no associated bruising
  • clean division of tissues along wound tract
  • profuse bleeding
  • no trace evidence
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what are the characteristics of chop wounds

A
  • mix of sharp and blunt force
  • abrasion with or without bruising of wound margins from wide blade
  • incised edges crushed on entry of the thick blade
  • variant of incision
  • longer than it is deep
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what are the early post mortem changes

A
  • algor mortis (chill of death)
  • livor mortis (darkening of death)
  • rigor mortis (stiffening of death)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what are the late post mortem changes

A
  • autolysis and putrefaction
  • mummification
  • adipocere
  • skeletonisation
17
Q

what is post mortem interval

A

the amount of time it has been since the person died

18
Q

what is algor mortis

A
  • loss of heat from the body due to conduction, convection and radiation and evaporation
  • cooling occurs immediately after death (external surface (skin) will cool more quickly than interior (organs))
  • rapid cooling of the body will occur initially until the body temp reaches the same temp as the atmospheric pressure then the rate of cooling is slowed down
  • only in temperate and cool climates
  • often unreliable, sometimes misleading
  • may be useful indicator of PMI in the first 24 hours
19
Q

what does the rate of cooling in algor mortis depend on

A
  • body size, obese people will cool more quickly because of large surface area
  • environmental temperature (fluctuations from day to night, sunny or overcast, heating in house)
  • drafts and humidity (body found outdoors, indoors near window, body found in sun)
  • clothing and coverings
  • person on tiled floor will cool more quickly than carpet
  • immersion (body cools more quickly in water than in air)
20
Q

what is livor mortis

A
  • seen as pinkish/purple discolouration
  • gravitational pooling of blood in blood vessels due to cessation of circulation in death
  • forms a horizontal fluid level
  • evident within internal organs also
  • compression of tissues prevents formation (contact pallor) where blood can’t pool e.g. bum if body lying on the floor will stay white bc compressed so no blood
  • poor indicator of PMI
  • may not be evident in all cases
  • development delayed and intensity affected by natural disease, blood loss (e.g. anaemia) and poisoning
21
Q

what is rigor mortis

A
  • muscle fibre relaxation requires ATP to break actin-myosin bonds
  • ATP requires oxygen
  • decerase in ATP post mortem means bonds cannot break causing rigor mortis
  • also calcium build up post mortem promotes actin-myosin cross bridging causing muscle contraction
  • due to residual ATP in body, rigor mortis doesn’t develop immediately after death until ATP reserve is depleted i.e. within hours after death
22
Q

what is the sequence of onset of rigor mortis

A
  • develops in all muscles
  • smaller muscles usually become completely involved sooner than the larger ones
  • eyelids then jaw and neck, small joints of hands and feet, medium joints of arms and legs, large joints of shoulder and pelvic organs
23
Q

what affects the rate of development of rigor mortis

A
  • body temp at death (hyperthermia increases onset, hypothermia delays onset)
  • rigor mortis occurs sooner in warmer temps
  • muscle activity immediately prior to death (e.g. exercise means quicker onset of rigor mortis - probs bc less ATP)
  • disappears with decomposition
  • ‘breaking’, if arm or leg is forcibly stretched out during autopsy rigor doesn’t re-develop in these areas
24
Q

what is autolysis

A
  • enzymatic breakdown of cells/tissues

- cannot be seen to the naked eye

25
Q

what is putrefaction

A

bacterial breakdown of cells/tissues

26
Q

what are the types of decomposition

A

maceration - sterile autolysis of foetus, specific to foetus in uterus, no exposure to maternal or environmental bacteria
wet putrefaction - enzymatic and bacterial
skeletonisation
adipocere - saponification of soft tissues (requires wet conditions)
mummification - desiccation of soft tissues (requires cool, dry conditions)

27
Q

what are the features of putrefactive bacteria

A
  • temperature dependent (optimal 21-38 degrees)
  • mainly commensal bacteria from GI or respiratory tract
  • pathogenic bacteria (organ/tissue specific infection or septicaemia)
28
Q

what is the sequence of putrefaction

A
  • green discolouration of lower abdomen due to overgrowth of colonic bacteria (within 2 days)
  • greenish black discolouration and swelling of face and neck due to gas production from bacteria (within 3-4 days)
  • reddish brown purge fluid may extrude from the nose and mouth (don’t confuse with blood)
  • gas formation causes diffuse swelling of the body, most noticeable in abdomen
  • skin slippage and blistering, hair slippage from scalp (days to a week)
  • marbling occurs due to breakdown of haemoglobin within blood vessels, prominence of blood vessels on skin (days to a week)
29
Q

what speeds up putrefaction

A
  • slow initial cooling
  • warm environment
  • high humidity
  • fever at time of death
  • infection
  • wounds/tissue disruption
30
Q

what slows down putrefaction

A
  • rapit initial cooling
  • cold environment
  • dry conditions
  • hypothermia at death
  • blood loss
  • embalming
  • burial
31
Q

what is mummification

A
  • desiccation of tissues in dry conditions
  • can take months to years
  • skin dries, shrinks and leathery
  • internal organs may decompose or be preserved
  • more common in infants (great surface area to mass ratio)
  • usually months but can start to occur within days to weeks if very arid conditions
32
Q

what is adipocere (saponification)

A
  • ‘grave wax’
  • transformation of body fat to oleic palmitic, and stearic acids by hydrolysis
  • appears yellow, white or brown and waxy; rare and occurs in humid or wet environments
  • moist conditions (submerged, water logged grave)
  • clostridium welchii causative bacteria
  • released fatty acid inhibit other bacteria
  • weeks to months
  • predominates in fatty tissues

principles of disease (19 decks)

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