Download Forensic Pathology PPT

FORENSIC PATHOLOGY
MISS COLABELLI
https://www.youtube.com/embed/KkNdCSW1n_g
DEFINITION OF DEATH
• Not all experts agree on exact time of death
• Irreversible cessation of blood circulation
• Heartbeat stops
• Cells begin to die and break down (autolysis)
• Cessation of all brain activity
CORONER VS. MEDICAL EXAMINER
• Corner
• Elected position that is more often found in rural areas
• Cannot perform autopsies
• Legally responsible for overseeing death investigation
• Medical Examiner
• Physician (usually a pathologist)
• Determines manner and cause of death
JOBS OF THE MEDICAL EXAMINER
• Identify the deceased individual
• Estimate the time and date of death
• Estimate the cause or manner of death
• Protect property of the dead
• Notify the next of kin
WHEN ARE AUTOPSIES PERFORMED?
• Sudden and/or unexpected death
• Public Health Concern or a mysterious disease
• Someone dies unattended by a physician
• Family requests an autopsy
• If an autopsy is not required by law, next of kin can request
• Laws vary by state
http://projects.propublica.org/forensics/
https://www.youtube.com/embed/udi8IpP3Uy8
PARTS OF AN AUTOPSY
• External Examination
• Bruising, cuts, wounds, etc…
• Internal Examination
• Weigh organs
• Check for abnormalities
• Preserved in formaldehyde
• Microscopic Examination
• Histology (study of tissues)
• Toxicology Report
• Blood, urine, bile, fluid from eye tests to look for medications,
drugs, alcohols or poisons
ESTIMATING TIME OF DEATH (TOD)
• Rigor mortis
• Livor mortis
• Algor mortis
• Stomach contents
• Vitreous humor
• Changes due to decomposition
• Entomology
• Botany
THE INVESTIGATION…
• Cause
• Manner
• Mechanism
• Time
CAUSE OF DEATH
• Specific changes in the body brought
about the cessation of life
• Blunt trauma to the head
• Bullet to the heart
• Heart attack
• Kidney or liver failure
• Cancer
• Asphyxiation
MANNER OF DEATH
• Reason for death
• Natural
• Homicide
• Suicide
• Accident
• Undetermined
• Manner explains how the cause of death
arose
MANNER – LEGAL DETERMINATION
HOMICIDE
• Death caused by the actions of someone else with
intent (homicide/murder)
• Death caused by the actions of someone else without
intent – negligence, inadvertent (manslaughter)
• Ex: planned drowning or shooting vs. fatal heart
attack as a result of abduction
HOMICIDE
LAWFUL
SELF-DEFENSE
Justifiable killing of
a suspect by police
1st DEGREE
The killing is
deliberate and
pre-meditated
UNLAWFUL
MURDER
MANSLAUGHTER
Committed with
malice aforethought
2nd DEGREE
The killing occurs
during the
course of a
felony
VOLUNTARY
“heat of passion”
INVOLUNTARY
Criminally negligent
or reckless conduct
• Suppose that Rosencrantz is driving a car and runs over and kills Guildenstern.
Rosencrantz might be:
•
Not guilty of a crime at all. However, if Guildenstern's family sues Rosencrantz in
a civil case, Rosencrantz might have to pay damages to Guildenstern's heirs if
Rosencrantz was negligent—that is, if Rosencrantz failed to use ordinary care.
•
Convicted of involuntary manslaughter. If Rosencrantz acted recklessly meaning that he was more than ordinarily negligent, by driving under the
influence of alcohol, for example–he could be convicted of involuntary
manslaughter. (Many states have separate statutes to deal with vehicular
manslaughter.)
•
Convicted of second degree murder. If Rosencrantz's behavior demonstrated
such an extreme disregard for human life that a judge or jury considers it malice
aforethought, second degree murder would be the crime. For example, if
Rosencrantz not only kills Guildenstern as a result of drunk driving, but does so
after his license had been taken away for several previous drunk driving
convictions, a judge or jury might convict him of second degree murder.
MURDER VS. MANSLAUGHTER
CASE EXAMPLE 1
• Facts: Fast Boyle is walking along a busy street.
Clay bumps into Boyle and continues walking
without saying, “sorry.” Angered by Clay’s
rudeness, Boyle immediately pulls out a gun and
kills Clay
MURDER VS. MANSLAUGHTER
CASE EXAMPLE 1
• Verdict: Boyle could probably be convicted of second
degree murder, because he killed Clay intentionally. A
judge or jury is unlikely to conclude that the killing was
premeditated, which would elevate the shooting to a first
degree murder. On the other hand, this wasn’t a kind of
heat-of-passion killing that equals voluntary
manslaughter. While Boyle might have been provoked in
some sense, the circumstances weren’t so extreme to cause
a reasonable person to lose control.
MURDER VS. MANSLAUGHTER
CASE EXAMPLE 2
•
Facts: Standing next to each other in a bookstore a few feet
away from the top of a flight of stairs, Marks and Spencer
argue over the proper interpretation of free will in Hobbes’s
philosophy. The argument becomes increasingly animated and
culminates when Spencer points a finger at Marks and Marks
pushes Spencer backwards. The push is hard enough to cause
Spencer to fall backwards and down the stairs. Spencer dies
from the resulting injuries.
MURDER VS. MANSLAUGHTER
CASE EXAMPLE 2
•
Verdict: Marks would probably be guilty of involuntary
manslaughter. It was criminally negligent of him to shove a
person standing near the top of a stairway. But the
circumstances don’t seem to suggest that his behavior was so
reckless as to demonstrate extreme indifferences to human life,
which would have elevated the crime to second degree
murder. If the evidence had indicated that Marks intended to
kill Spencer with the push, a judge or jury would have had to
determine whether the extent of the provocation made the
homicide voluntary manslaughter.
MURDER VS. MANSLAUGHTER
CASE EXAMPLE 3
• Facts: Lew Manion comes home to find that his wife Lee
has been badly beaten and sexually abused. Manion
takes Lee to the hospital. On the way, Lee tells Manion
that her attacker was Barnett, the owner from the tavern
that she and Manion occasionally visit. After driving Lee
home from the hospital about four hours later, Manion
goes to a gun shop and buys a gun. Manion then goes to
the tavern and shoots and kills Barnett.
MURDER VS. MANSLAUGHTER
CASE EXAMPLE 3
• Verdict: Manion could be convicted of first degree
murder, because the time for reflection and his purchase
of the gun indicates premeditation and deliberation.
Voluntary manslaughter is a somewhat less likely
alternative because a judge or jury could find that the
heat of passion had cooled even though Manion
remained angry at the time he acted.
MANNER – LEGAL DETERMINATION
SUICIDE
• Death caused by the intent to end one’s own life
• Ex: death by someone who knowingly engages in
dangerous/reckless behavior,
• Dies from a fall
• Terminally ill patient refuses to eat and dies of
malnourishment
MANNER – LEGAL DETERMINATION
ACCIDENTAL VS. NATURAL
• Accidental
• Violent unexpected death not caused by intentional
or criminal act of another
• Natural
• Death caused by naturally occurring illness or
disease
• Ex: heart attack, stroke, cancer, SIDS, influenza, birth
defects, medical procedures, natural disasters
MANNER – LEGAL DETERMINATION
UNDETERMINED
• When a classification cannot be reasonably made
• Ex: lack of evidence or more than one factor at work
MECHANISM OF DEATH
• Biological or physiological means by which a
person dies
• Ex: Person sustains multiple impact injuries from an
auto accident
• Blunt force trauma is the CAUSE of death
• Exsanguination is the MECHANISM of death
• Accidental homicide or suicide (depending on evidence) is the
MANNER of death
POST MORTEM INTERVAL (PMI)
• Time between actual death and time body is
found
• More accurate in the first 72 hours of death
• The longer the PMI the more uncertain
• Why is determining TOD important?
TOD RIGOR MORTIS –
THE RIGIDITY OF DEATH
• Begins in 2-4 hours
• 12-24 hours at maximum
• Fully relaxed after 48 hours
• First observed in smaller muscles (jaws, fingers,
toes)
• Produces “goosebumps”
• Larger muscles soften at first
RIGOR MORTIS
• Live muscle fibers slide back and forth
• After death, muscle fibers becomes locked in a
flexed positon
TOD RIGOR MORTIS –
THE RIGIDITY OF DEATH
Observation
Approx. Time Scale
Body is at its more rigid state
Just over 12 hours
No visible signs of rigor
Less than 2 hours or more than 48
hours
Stiffness generally disappears
After 36 hours
FACTORS AFFECTING RIGOR MORTIS
• Ambient temperature
• Weight of the body
• Type of clothing or lack thereof
• General health of the person at time of death
• Level of physical activity at time of death
• Sun exposure
TOD – LIVOR MORTIS
• Lividity
• With decomposition, blood seeps down and settles in
the lower part of the body
• RBC turn blueish-purple
• Begins about 2 hours after death
• Discoloration becomes permanent after 8 hours
• Ambient temperature affects the speed of lividity
• Can determine the position of the body during the
first eight hours
• If a person dies in a chair and is moved to face down after
8 hours. How do you know they died in a chair?
TOD – ALGOR MORTIS
• Body heat falls after death
• 15 degrees/hour immediately after death
• Slowly to less than 1 degree/hour after about 12 hours
• Heat loss is affected by ambient temperature
• Corpse temperature is measured by a thermometer
inserted into the liver TOD is expressed as a range of time
• Factors
•
Clotting, surrounding temperature, moisture, humidity, amount of fat
tissue, diseases, where the body was found (buried, water, in sun),
insect activity
TOD
Stomach/Intestines Contents
STATE OF CONTENTS
TIMING OF DEATH
Undigested food present in the
stomach
Zero to 2 hours after the last meal
Stomach is empty but food found in
small intestine
Death occurred at least 4-6 hours
after a meal
Small intestine is empty, waste
found in large intestine
Death occurred 12 or more hours
after meal
TOD
STAGES OF DECOMPOSITION
A. Within 2 days
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•
•
•
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B. After 4 days
C. Within 60 days
Discoloration of the face
The skin sloughs off
The skin blisters
Green & purplish staining from blood decomposition
The corpse bloats
Eyeballs & other tissues liquefy
The abdomen swells
Marbling appearance on the skin
TOD Stages of Decomposition
STAGE
WHAT HAPPENS DURING DECOMPOSITION
Initial decay
Corpse appears normal on outside but is starting to
decompose due to bacteria and autolysis
Putrefaction
Odor of strong decaying flesh is present and
corpse appears swollen
Black putrefaction
Very strong odor, parts of flesh appear black,
gases escape and the corpse collapses
Butyric
fermentation
Corpse is beginning to dry out, most of the flesh is
gone
Dry decay
Corpse is almost dry, further decay is very slow due
to lack of moisture
Time
Process
Within 2 days
Cell autolysis
Green & purple staining due to decomposition of
blood
Skin looks marbled
Face becomes discolored
After 4 days
Skin blisters
Abdomen swells with CO2 released by bacteria
Within 60 days
Corpse bloats with CO2 causing chest/abdomen
cavities to burst & collapse
Fluid leaks from body openings as cell membranes
rupture
Eyeballs & tissues liquefy
Skin sloughs off
TOD
CHANGES OF THE EYE
• Surface of the eye dries
• Forms a thin film
• 2-3 hours for open eyes
• Up to 24 hours for covered eyes
• Potassium accumulates inside vitreous humor
• Buildup of K+ ions can be used to estimate TOD
INFORMATION FROM AUTOPSY
WHO ARE YOU?
• You can identify a body by
• Family member or friend
• License, passport, jewelry, etc. found on body
• Tattoos, scars, birthmarks, etc.
• Biomedical scan (dental, x-ray, MRI, etc)
• Fingerprint
• DNA
INFORMATION FROM AUTOPSY
WHEN DID YOU BECOME ILL, HURT OR DIE?
• Rigor mortis, livor mortis, algor mortis
• Bruises by color change
• Progression of healing wound
• Contents of stomach
INFORMATION FROM AUTOPSY
WHERE DID YOU GET HURT OR DIE?
• Evaluation of death scene
• Livor mortis can determine if body was moved
• Items found in body cavity
• Ex: pollen in sinuses
INFORMATION FROM AUTOPSY
DID YOU DIE BY ACCIDENT/VIOLENCE/NATURAL
CAUSES OR SOME COMBO?
• Autopsy examination to determine whether it was
suicide, accident, homicide, etc
• Type, size, location, direction of wounds/injuries
• Ex: gunshot, puncture, laceration
STEPS IN AN AUTOPSY
1. Access & control of remains
• Chain of custody
• Record keeping – photographs
2. External examination
• Overall health/description of person
• Marks/scars/signs of trauma recorded and
photographed
• Fingernails scraped/hands tested for GSR,
fingerprints, fibers
• Biomedical – X-ray/MRI/CAT scan
STEPS IN AUTOPSY
3. Opening thoracoabdominal and brain cavities
4. Removal of organs
• Weigh, measure, inspect
• Tissue and fluid samples
5. Sample evaluation and analysis
6. Closure
TYPES OF TRAUMA
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Penetrating
•
Projectile wounds
•
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Non-penetrating
•
Knives
Glass
Blunt force trauma
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•
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Bullets, arrows, flying
debris
Sharp force trauma
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Vehicular accidents
Falls
Assaults
Asphyxia
•
•
Strangulation
Suffocation
FIREARMS INJURIES
• Permanent Cavity Damage
• Direct impact of bullet on tissue along the path of the bullet
• Temporary Cavitation
• Brief cavity formed behind the bullet
KINETIC ENERGY
• KE increases as mass or velocity of bullet increases
• Larger and slower bullets crush more tissue
• Faster bullets stretch more with little crushing
• Bone beveling can determine direction of a bullet
ENTRANCE WOUND
• Typically smaller
• Can usually
determine caliber
of bullet
TYPES OF ENTRANCE WOUNDS
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Contact
•
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Muzzle >2 inches from wound
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Possible muzzle impression
•
•
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Leaves visible soot/skin
searing
Intermediate range
•
Muzzle 2 inches to 2 feet
from wound
•
Leaves stippling on skin
Distant range
•
Muzzle >2 feet from wound
Leaves clean, star-shaped
wound
Atypical wounds
•
Grazing, surface lodged,
other unusual impacts
EXIT WOUNDS
• Irregular, large, lacerated
• Bone beveling
• Generally larger than entrance wounds
FORENSIC RADIOLOGY
• X-ray
• Permanent record of body structures
• Quickly find foreign objects
• Compare antemortem and postmortem radiographs for ID
purposes
• CAT scan
• 3D X-ray images
• Search for internal injuries/bone damage
• Aids in determining pathway of projectiles
FORENSIC RADIOLOGY
• MRI (Magnetic Resonance Imaging)
• Used with X-ray and CAT scan data for facial
reconstruction
• Improved soft tissue visualization
• Virtopsy
• Use CAT/MRI to form permanent, highly detailed and
accurate representation of both internal and external
structures along with biochemical profile
• Place image in virtual crime scene
https://www.tii.se/projects/autopsy
http://www.pbs.org/wgbh/pages/frontline/post-mortem/