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Postmortem Changes Flashcards

1
Q

What are the immediate changes?

A

Happens within few mins
Loss of brain func (earliest), then circulation, and respiration

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2
Q

What are the early changes?

A

Occurs within hours to days
Skin, eye changes
Algor mortis (cooling)
Livor mortis (staining)
Rigor mortis (rigidity)

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3
Q

What are the late changes?

A

Occurs within days to weeks
Putrefaction
Adipocere
Mummification

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4
Q

What are the skin changes?

A

Pallor
Loss of elasticity

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5
Q

What are the changes in muscle?

A

Primary flaccidity of muscle
Loss of muscle tone
Drooping of jaw
Relaxation of sphincter

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6
Q

What are the eye changes?

A

Few mins - railroad appearance of retinal vessels
3-6 hrs - tache noire sclerotica (triangle shaped opacities) & dust deposition (reddish brown) in sclera
1-6 hrs - corneal opacity
Flaccidity of eye ball
Dilation of pupil
Loss of corneal & pupillary reflexes

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7
Q

When does algor mortis occur?

A

15 minutes after death

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8
Q

Instrument used and sites that can be used measure temperature

A

Instrument - thanotometer
Sites - rectal, sub-hepatic, intra-tracheal, intranasal, middle ear cavity

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9
Q

Formula to calculate PM interval (hrs)

A

PM interval (hrs) = (normal body temperature - rectal temperature)/rate of temperature fall (hrs)

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10
Q

What is the usual rate of fall in temperature?

A

0.4-0.7 per hour

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11
Q

Factors affecting algor mortis

A

Location of the body
Naked/clothed
Weather/season
Environment (water/underground)

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12
Q

PM caloricity

A

Body remains warm for 1-2 hours, seen when body core temperature increases at time of death
Eg. Heat stroke, pontine hemorrhage, strychine poisoning, tetanus, septicemia and cholera

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13
Q

MLI of algor mortis

A

Time since death

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14
Q
A
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15
Q

What is livor mortis?

A

Bluish/purplish discoloration of skin after death due to settling down of blood in the toneless capillaries in the dependent portions of the body.

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16
Q

When does PM lividity appear?

A

Begins 1-2 hours after death (patches)
Completes by 4-6 hours

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17
Q

When does PM lividity get fixed?

A

Hemolysis & diffusion of pigments to skin by 6-8 hours

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18
Q

What is contact pallor?

A

Areas of tight contact -> compression of vessels leading to no PM staining
E.g tight clothing, at pressures points

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19
Q

Conditions where PM lividity will not develop

A

Tossing of body in flowing water
Severe anemia
Hemorrhagic/hypovolemic shock

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20
Q

Difference between PM lividity and bruise

A

PM - seen in the skin, on dependent parts, no swelling, uniform in color and on incision slight oozing blood seen which can be washed away

Bruise - seen under the skin anywhere, swelling maybe present, different colors and it extravasated blood

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21
Q

MLI for PM lividity

A

Sign of death
Time since death
Position of the body at the time of death
Whether body was moved
Cause of death

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22
Q

What is rigor mortis?

A

Stiffening of the body after death
3 phases - primary flaccidity, rigor mortis, secondary flaccidity

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23
Q

What is the pathophysiology of rigor mortis?

A

After death, ATP depletes
- rigor begins when ATP decreases to 85% of its storage
- rigor maximum when ATP decreases to 15% of its storage

Then actin myosin filaments are bound by dehydrated , stiff, gel-like mass causing the muscles to become rigid

24
Q

Explain the rule of 12

A

Rigor mortis begins to appear 1-2 hours after death. Gets well established in 9-12 hours. Maintained in that state for 12 hours and then after another 12 hours it disappears.

25
Order of appearance & disappearance of rigor mortis
Starts appear/disappear from face, neck, trunk, arms and lower limbs Appears/disappears earlier in involuntary muscles (heart within an hour)
26
Factors affecting rigor mortis
- Temperature - Condition of muscles before death - exhaustion, convulsion, diseases - Age factor
27
MLI of rigor mortis
Time since death Position of the body at the time of death
28
Heat-stiffening
Heat exposure leading to protein coagulation causing body to stiffen
29
Cold stiffening
Body in cold chamber causing joint fluids to freezes leading to stiffness of body
30
Gas stiffening
Gas produced during decomposition leading to bloating and stiffness of body, protrusion of tongue and eyeball
31
Cadaveric spasm
Spasm of group of voluntary muscle in use at time of death; antemortem finding
32
Define decomposition
The final stage of dissolution of body tissues resulting in breaking down of complex organic body constituents into simpler inorganic ones Autolysis, Putrefaction
33
What is autolysis?
Softening & liquefaction of tissues under sterile conditions E.g IUD maceration of fetus
34
What is putrefaction?
Produced by action of microorganisms (bacterial enzymes) that acts on protein and fats Blood being the medium for bacterial growth
35
What are the features of putrefaction?
Color changes Evolution of gases Liquefaction of tissues
36
Describe the color changes
1st external sign is the greenish discoloration of right iliac fossa seen within 12-24 hours (in summer) and 1-2 days (in winter) Bacterial spread + hemoglobin forming derivatives of HB causing this greenish-black-sulphmethhaemoglobin This spreads to abdomen, genitalia, chest, neck, face (purplish, greenish, greenish-black) Within 36-48 hours, there will be marbled appearance of the skin
37
Describe the evolution of gases
12-24 hrs - gas accumulates in intestine 24-48 hrs - gas in tissues, cavities & hollow viscera 2-3 days - post mortem blister formation, skin slippage, uterus & anal prolapse
38
What are the features that gets bloated and distorted?
- Distension of face, genitalia and abdomen - Eyes bulging, tongue forced out, swollen lips - Diaphragm forced upwards (postmortem purge) - Sphincter relax - urine & faeces may escape
39
Describe liquefaction of tissues that occurs in 3-7 days
- bursting open of abdomen & thorax - degloving of skin of palm & sole - teeth, hair & nails: loose & pulled put easily
40
Describe liquefaction of tissues that occurs from 5-10 days
Collequative necrosis - soft tissues: thick, semi-solid, black masses - separate from bones & falls off - finally - cartilages & ligaments softens
41
When does skeletonization occurs?
1-3 months in open air 2-6 months if buried More time if coffined
42
Earliest sign of putrefaction of internal organs
Reddish brown discoloration of inner surface of aorta & other vessels
43
Early putrefaction in which internal organs?
Larynx & trachea Stomach & intestine Spleen Omentum & mesentery Liver (foamy liver) Brain Gravid uterus
44
Late putrefaction in which internal organs?
Lungs Heart Kidneys Oesophagus, diaphragm Bladder Blood vessels Prostate & uterus
45
Factors influencing putrefaction
1. Atmospheric temp - bacterial growth occurs in 70-100 F (20-40 C) 2. Medium of disposal - Casper’s dictum (air:water:burial = 1:2:8) 3. Cause of death 4. Clothing on the body
46
What is adipocere?
Occurs within 3-6 months; can be 3-15 days in india A modified form of putrefaction where hydrolysis and hydrogenation of pre-existing unsaturated fats occurs & converts into firmer saturated fatty acids
47
What are the pre-requisites for adipocere to occur?
- abundance of moisture - hot & humid weather - abundance of adipose tissue - presence of bacteria (clostridium welchii)
48
Features of adipocere
Initially - soft, greasy, pale white Later - dry, hard, yellowish, brittle Rancid/sweetish odor Inflammable Floats in water, dissolves in alcohol/ether
49
What is mummification?
Occurs within 3 months - 1 year A modified form of putrefaction where dehydration and desiccation of tissues occurs
50
What are the pre-requisites for mummification to occur?
- absence of moisture - dry & warm climate - free circulation of air
51
Describe the appearance of mummification
- shriveled, dry, leathery, parchmentised, stretched tightly across anatomical prominences - practical odorless - internal organs are shrunken, hard, brown-black as a single mass
52
MLI of adipocere & mummification
- Features are unaltered: can establish identity and cause of death - time since death
53
What is forensic entomology?
Study of insect that infest dead bodies to aid legal investigations There are 8 successive waves of invasion (beginning of putrefaction to skeletonization)
54
Types of insects that infest on dead bodies
Blowflies (calliphoridae) - bluebottle, greenbottle, black blowfly Flesh fly (sacrophagidae) - infest open wounds House fly (muscidae) Beetle, mite, moth, bee, wasp
55
What is the life cycle of blowfly?
Laying egg - 18-36 hrs Larvae (maggot) - 12-24 hrs Pupae - 4-5 days Young fly (nymph) - 4-5 days
56
MLI of forensic entomology
Time since death = A+Bx(cd) - A = stage of invasion (hrs, days, wk, month) - B = stage of life cycle (hrs, day) - cd = climatic factor correction Detection of poison

Forensic (11 decks)

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