Ch 12 Postmortem Pathology

7/27/2019 Ch 12 Postmortem Pathology

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Forensic Pathology

- postmortem investigation of

sudden or unexpected death ortrauma to the living


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Role of the Forensic Pathologist

4 broad determinations to be made:

A. Cause of Deathmedical diagnosis (the injury)

B. Mechanism of Deathhow the injury produced

death (arrhythmia, exsanguination)C. Manner of Death

1. Homicide 2. Suicide 3. Accidental 4. Natural Causes

D. Time of Death


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Time of Death

Can estimate time of death from

body changes

estimate: [98.6 oFrectal temp]/1.5

insect action (forensic entomology)

stomach contents (stage of digestion)

last known activity (last sighting, newspaper/mail)


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The Body Farm

1 acre of land owned by the University of Tennessee


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Normal Postmortem Changes

1. Algor mortis: body cooling

2. Rigor mortis: body stiffening

3. Livor mortis: (lividity) blood settling

4. Putrefaction: destruction of body tissue by

bacteria


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Algor mortis

Cooling of the body

after death.

Best indicator of

TOD in 1st 24 hrs

Taken:

Rectal

Liver


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Algor mortis

Body cools approx 1.5 degrees C/hr

Skinny cools faster

No clothes cools fasterIn water cools much faster

normal tempmeasured temp/ 1.5 = # hrs


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Rigor Mortis

Rigor: stiffening of

muscles due to build

up of salts.

Begins: 12 hourspost mortem

face, arms,

abdomen, legs Takes: 12 hours to

get fully stiffened

Then starts to go

away in same order


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Rigor

Begins: 12 hours post mortem

face, arms, abdomen, legs

Takes: 12 hours to get fully stiffened

Then starts to go away in same order

Face, arms, abdomen, legs


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Rigor Mortis

Body warm not stiff less than 3 hours

Body warm stiff 3-8 hours

Body cool stiff 8-36 hours

Body cool not stiff more than 36 hours


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Livor Mortis

Lividity: red/purple

coloration of skin.

Due to settling of

blood after death

Skin will appear

white in areas that

were compressed.


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Lividity will appear

in about 2 hours.

Areas will turn white

if you press

Lividity will be set

after 5 hours


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Normal Postmortem Changes

1. Algor Mortis

2. Rigor mortis

3. Livor mortis

4. Putrefaction


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Decomposition

2 days post mortem

Marbling neck and shoulders

1st red then green

From bacteria getting into subQ tissue

bloating from gases created by bact.

Organs decompose in order:

Stomach and intestines, heart and liver

Musculature


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Trauma to the Human Body

Role of the Pathologist

1. Determine type of wound

2. Measure the dimensions (length, width,

depth)

3. Position relative to anatomical landmarks

4. Determine initial location if wound involves

cutting, slashing, etc.

5. Determine height fromheel


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Lacerations


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I ncised Wounds

Slash Stab


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Abrasions


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Contusions

Color changes a bruise goesthrough can give rough

estimate of time of injury

Dark blue/purple (1-18 hours)Blue/brown (~1 to 2days)

Green (~ 2 to 3 days)

Yellow (~3 to 7 days)

Assumes person is healthy.


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Stab Wounds

Laceration is a tearing injury due to friction or impact with a blunt

object.

Puncture is a penetrating injury due to pointed object without a blade,

such as an ice pick

Serrated blades produce the same smooth edges as nonserrated blades.

Abrasion is a friction injury removing superficial layers of skin,

Contusion is a bruise due to rupture of small blood vessels.

Slash wounds tend to look like bullet wounds that only graze the

surface of the skin. Other types of slash wounds are called "hesitation

marks" commonly found in suicide cases. They are typically rectangular

in shape; i.e., their cuts are as wide and they are long.

Incision wounds: cutting with a blade, always have lengths greater than

their depth


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Gunshot Wounds

Things for pathologist to learn:

type of firearm

distance of gun to victim

entrance vs exit wounds

track of projectile


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Gunshot Wounds

Starring of a

contact wound

barrel touching the

skin

Stippling powder burns on

the skin when the gun is

inches to a few feet from thevictim


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Gunshot wounds

Contact Wound: Muzzleapplied to skin at shooting.

Impression of muzzle burnedaround entrance wound

Close Range (6-8 inches):

StipplingIntermediate Range (1- 3 ft.):

hot fragments of burninggunpowder; ball

Distant (greater than 3 ft.):No soot or burning of wound

marginsEntrance wound: surrounding

skin dragged in

Exit wound: skin pushed out
http://images.google.com/imgres?imgurl=www.mel.nist.gov/div821/webdocs-13/bullets-1.jpg&imgrefurl=http://www.mel.nist.gov/div821/webdocs-13/bullets-casings.htm&h=182&w=325&prev=/images?q=bullets&svnum=10&hl=en&lr=&ie=UTF8&oe=UTF8


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Close range

Close Range

(6-8 inches):

Entrance surrounded

by stippling- HOTsoot traveling for

short distance;

BURNS


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Intermediate range

Intermediate range

1-3 feet

Gunpowder ball


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POISONING

Determined by discolorations

on bodyCherry- red lividity is sign of

carbon monoxide poisoning

Toxins give off unusual

odors

Certainty of diagnosis

requires toxicological

confirmation

Samples taken of stomach,vomit, kidney, lungs, liver
http://images.google.com/imgres?imgurl=www.uscg.mil/hq/nsfcc/nsfweb/images/FluraChemical/poison%20gas%20next%20to%20phosgene.jpg&imgrefurl=http://www.uscg.mil/hq/nsfcc/nsfweb/nsfcc/ops/Response/archive/FluraChemical/photo.html&h=640&w=480&prev=/images?q=poison&start=40&svnum=10&hl=en&lr=&ie=UTF8&oe=UTF8&sa=Nhttp://images.google.com/imgres?imgurl=www.drugabuse.gov/ResearchReports/Prescription/pillbottles.gif&imgrefurl=http://www.drugabuse.gov/ResearchReports/Prescription/prescription2.html&h=216&w=253&prev=/images?q=pill+bottles&svnum=10&hl=en&lr=&ie=UTF8&oe=UTF8http://images.google.com/imgres?imgurl=www.uwm.edu/Dept/EHSRM/PHOTOS2/poison.jpg&imgrefurl=http://www.uwm.edu/Dept/EHSRM/LAB/labgascyl.html&h=287&w=220&prev=/images?q=poison&start=100&svnum=10&hl=en&lr=&ie=UTF8&oe=UTF8&sa=Nhttp://images.google.com/imgres?imgurl=www.box.net.au/~gkhume/poison.jpg&imgrefurl=http://www.box.net.au/~gkhume/poisons.html&h=149&w=248&prev=/images?q=poison&start=80&svnum=10&hl=en&lr=&ie=UTF8&oe=UTF8&sa=Nhttp://images.google.com/imgres?imgurl=www.puzzlesink.com/poison.gif&imgrefurl=http://www.puzzlesink.com/ssigns2.HTM&h=350&w=360&prev=/images?q=poison&start=60&svnum=10&hl=en&lr=&ie=UTF8&oe=UTF8&sa=Nhttp://images.google.com/imgres?imgurl=www.psc.state.sc.us/consumer/information/images/poison.gif&imgrefurl=http://www.psc.state.sc.us/consumer/information/Clear,%20Cool%20&%20Costly.htm&h=350&w=195&prev=/images?q=poison&start=20&svnum=10&hl=en&lr=&ie=UTF8&oe=UTF8&sa=N


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BURN

Scorching or burning of skin leads to sepsis and is

immediate cause of death

Wounds caused by heat, chemicals, or electricity

Fire victims found in pugilistic position: clenched fists,resembling pose of boxer

Heat causes protein in body to contract

Blood and lung samples taken


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Blunt force trauma

Blunt Force trauma results fromclubbing, kicking, or hitting the victims.

The blow produces a crushing effect

on the human body, resulting incontusions, abrasions, lacerations,fractures, or rupture of vital organs.

Red-blue contusions are alwayspresent, but this varies by the weight ofthe individual (obese people bruise easierthan lean people)

Ch 12 Postmortem Pathology

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