Forensic Pathology
CAUSE OF DEATH, MANNER, MECHANISM
Role of the Medical Examiner
 How is a coroner different from an ME?
 Coroners are elected officials. They require no
formal training.
 The coroners are actually part of the judicial body, a
tradition that comes from England.
 Around the early 1900s, local scandals were
becoming more widespread by coroners that had no
training.
 Medical examiners began replacing coroners in large
cities. They required formal training and had to pass
a test to be licensed.
Pathologists
 Pathologists began appearing in hospitals as
microscopes became more advanced, in the mid
1850s.
 Pathologists studied diseases, causes and diagnosis.
 Many pathologists study tissues and biological fluids.
 By the end of WWII, forensic pathology was a
recognized specialty and now, medical examiners in
large cities are usually required to be forensic
pathologists as well.
Training Required
 Medical School- 4 years
 Post-medical school training, usually in a hospital
pays about $20,000 per year
 One more year of post graduate training is required
and usually pays around $50,000 per year.
 A 2-3 day examination must be passed at this time to
become board certified.
 Several also go to law school to obtain a J.D. (juris
doctor) degree since there is so much intersection
with the law.
Duties of a Forensic Pathologist
 Reviewing Medical history of victim
 Reviewing witness statements
 Scene examination (especially when death is
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complicated)
Autopsy examination- better term is necropsy
Obtaining appropriate samples for toxicology,
microscopic examination and DNA
Photography
Report preparation
Testimony in court
Cause of Death
 The disease or injury that led to death
 The cause is the underlying cause, even if other
complications or contributing factors were involved.
 Mechanism of Death- the biological or
physiological abnormality produced by the cause of
death that is incompatible with life
Manner of Death
 There are only 4:
 1) Homicide- acts from which a reasonable person
would have expected bodily harm or death
conducted by another party
 2) Suicide- acts from which a reasonable person
would have expected bodily harm or death
conducted by ones self
 3) Accidental- trauma occurring from acts no
reasonable person would have anticipated producing
bodily harm or death
 4) Natural- solely caused by disease
Time of Death
 Rigor mortis- stiffening of muscles that occurs when
glycogen (which causes contraction of muscles) is
used up but not reformed
 Usually
begins around 4 hours after death and
subsides between 24 and 36 hours
 Exercise before death and electric shock can quicken
the presence of rigor mortis
Time of Death
 Livor mortis or lividity- discoloration of the body where
red blood cells settle after blood stops circulating
 Can be seen within an hour of death in light skinned
individuals
 May not be seen in dark skinned individuals, or those
who lost a lot of blood volume
 Slowly disappears with decomposition after 36 hours
 Algor mortis- cooling of the body that occurs after death
(assuming ambient temperature is lower than body
temp.) Assumed that a nearly nude body exposed to 1820° C temp will decrease 1.5° C per hour for 8 hours after
death. Many extenuating circumstances can affect body
temp!
Classification of Traumatic Deaths
 1) Mechanical- sharp and blunt force trauma
 2) Thermal- hypo or hyperthermia, exposure to excessive cold or
hot temps.
 3) Chemical- death by use of drugs or poison, ethanol involved
deaths account for more than 50% of traumatic deaths
 4) Electrical- passage of electrical current through the body to
produce ventricular fibrillation causing death
 Note: Asphyxial death, death that occurs as a result of lack of
oxygen to brain, overlaps other causes: may be due to strangulation
(mechanical), poisoning (chemical) or low voltage electrocution
(electrical).
Mechanical Trauma
 1)
Sharp force traumainjuries received from sharp implements,
like knives, swords, axes
Amount of fore required to exceed tensile
strength of tissue is much less than blunt
objects require
Produce incised wounds, which have sharp
edges that distinguish sharp force from
blunt force injuries
Death most commonly arises from
exsanguination, when a major artery or the
heart is damaged
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Mechanical Trauma
 2) Blunt force trauma-
- most commonly causes death when the brain
has been significantly damaged
- however, lacerations, cuts from blunt force
trauma, can cause exsanguination also
- firearms cause a special kind of blunt force trauma,
several distinctions can be made including type of weapon,
velocity of projectile
- High velocity projectiles (greater than 300 m/s) are
usually only seen by high powered rifles (hunting and
military)
Mechanical Death
 Blunt force trauma continued-
- Often times contusions are present, accumulation of
blood in tissues outside of the blood vessels. The pattern
in the contusion may be transferred from the striking
object.
 - Hematomas are “blood tumors” which are contusions
with more blood present.
 Gunshot exit wounds are typically lacerated, and most are
larger than entrance wounds.
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Chemical Trauma
 Ethanol is the drug that is complicit in 50% of all
traumatic deaths. It can also kill directly through
alcohol poisoning. People generally go into a coma
and then die due to lack of oxygen.
 Carbon monoxide and cyanide are also poisons that
are used to induce death.
 In California, the authorities used potassium cyanide
tablets that were dropped in hydrochloric acid to
produce hydrogen cyanide gas in gas chambers.
Electrical Trauma
 Low voltage electrocution causes ventricular fibrillation, this is defined as a
non-propulsive quivering that leads to nonresucitability within minutes.
 High-voltage direct current (DC) tends to cause a single muscle
spasm, often throwing the victim from the source, resulting in a shorter
duration of exposure but increasing the likelihood of traumatic blunt injury.
 Alternating current (AC) is said to be about three times more
dangerous than direct current of the same voltage, because
continuous muscle contraction, or tetany, occurs when the muscle
fibers are stimulated at between 40 and 110 times per second. The
frequency of electrical transmission used in the United States is 60 Hz. Tetany
occurs even at very low amperages.
 It has been customary to use the terms "entry' and "exit" to describe electrical
injuries. Particularly with AC, this is clearly a misnomer and the terms should
correctly he "source" and "ground." The hand is the most common site of
contact as it grasps a tool coming into contact with an electric source. Although
all the muscles of the arm may be tetanically innervated by a shock, the flexors
of the hand and forearm are much stronger than the extensors so that the hand
grips the source of the current. At currents above the let-go threshold (6 to 9
mA), this can result in the person's being unable to release the current source
voluntarily, prolonging the duration of exposure.
Legal Definitions of Homicide
 “Homicide is a legal term for any killing of a human
being by another human being. Homicide itself is not
necessarily a crime --some homicides are legal, such
as a justifiable killing of a suspect by the police or a
killing done in self-defense -- but unlawful
homicides are classified as crimes like murder and
manslaughter.”~http://www.nolo.com/legal-encyclopedia/homicide-murdermanslaughter-32637.html
First Degree Murder
 The rules vary somewhat from state to state as to what
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circumstances make an intentional killing first degree
murder. The following circumstances commonly make an
intentional killing first degree murder:
The killing is deliberate and premeditated.
The killing occurs during the course of a dangerous
felony.
The killer uses an explosive device such as a bomb.
In terms of punishment, many states have mandatory
minimum sentences for murder. The mandatory minimum
for first degree murder is almost always higher than for
second degree. Defendants convicted of first degree murder
can also be eligible for a state's ultimate penalty. Currently,
in 36 states and under some federal laws, the ultimate
penalty is death. In others, the ultimate penalty is life in
prison without the possibility of parole (LWOP).
Second Degree Murder
 Defendants convicted of second degree murder are often
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sentenced to a term of years rather than to life in prison
and are almost always eligible for parole.
Second-degree murder is ordinarily defined as:
1) an intentional killing that is not premeditated or
planned, nor committed in a reasonable "heat of
passion"; or
2) a killing caused by dangerous conduct and the
offender's obvious lack of concern for human life.
Second-degree murder may best be viewed as the middle
ground between first-degree murder and voluntary
manslaughter.
Manslaughter
 Manslaughter (in some states called third degree
murder) is an unlawful killing that does not involve
malice aforethought. The absence of malice
aforethought means that manslaughter involves less
moral blame than either first or second degree
murder. Thus, while manslaughter is a serious crime,
the punishment for manslaughter is generally less
than it would be for murder.
 Voluntary manslaughter. This is often called a
"heat of passion" crime.
Manslaughter
 Involuntary manslaughter. A killing can be
involuntary manslaughter when a person's reckless
disregard of a substantial risk results in another's
death. Because involuntary manslaughter involves
carelessness and not purposeful killing, it is a less
serious crime than murder or voluntary
manslaughter.
Murder and 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.
 Verdict: Boyle could probably be convicted of second
degree murder, because Boyle killed Clay intentionally. A
judge or jury is unlikely to conclude that the killing was
premeditated, which would elevate the shooting to first
degree murder. On the other hand, this was not a heat of
passion killing that might reduce the conviction to
voluntary manslaughter. While Boyle might personally
have been provoked into killing Clay, the circumstances
were not so extreme that many ordinary and reasonable
people would have been provoked to kill.
Murder and 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.
 Verdict: Marks would probably be guilty of involuntary
manslaughter. It was criminally negligent of Marks to shove
a person standing near the top of a stairway. But
circumstances don't suggest that Marks's behavior was so
reckless as to demonstrate extreme indifference to human
life, which would have elevated the crime to second degree
murder.
Murder and 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 of a 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.
 Verdict: Manion could be convicted of first degree murder,
because his purchase of the gun suggests that the shooting was
intentional and premeditated. Voluntary manslaughter is a
somewhat less likely alternative. Most judges and jurors are likely to
think that enough time elapsed between the time Manion found out
about Lee's injuries and the time he shot Barnett for any heat of
passion to have cooled. Manion should have left his gun at home
and reported the crime to the police.