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Investigation of
Traumatic Deaths
Ch 4
Pages 43-58
Terminology – Part 1
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Mechanism of Death - biochemical and/or physiological abnormality
produced by the cause of death which is incompatible with life
Manner of Death – one of the four ways death can be caused; natural,
accidental, suicidal, or homicidal.
Liver mortis – the postmortem reddish discoloration of the body due to the
settling of red blood cells due to gravity
Algor mortis – the postmortem cooling of the body.
Lacerations – injury produced by blunt instruments; characterized by
surface abrasion, bridging vessels, and nerves with irregular margins.
Exsanguinations – death after a significant amount (usually half or more)
of blood is lost. (Bleeding to death)
Contusion – bruise; leakage of the blood from damaged blood vessels into
tissues.
Hematoma – a tumor of blood caused by leakage from damaged blood
vessels; it contains enough blood to form a blood filled space.
Part 2
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Handgun – firearm designed to be fired by the hand
Shotgun – smoothbore firearm designed to be fired from the
shoulder
Contact wounds – a skin injury produced by a weapon in contact
with or a fraction of an inch from the skin when discharged.
Explosion – sudden conversion of potential energy to kinetic energy
accompanied by physical destruction of the container or structure
via a high pressure wave front.
Stippling – disposition of fragments of powder into the skin as the
result of a gunshot wound of relatively close range; also called
powder tattooing.
Intermediate range gunshot wounds – firearm wound that shows
stippling, but no smoke; generally indicates a distance of a few
millimeters to a meter from skin to gun muzzle at the time of
discharge.
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Distant wound – firearm wound that lacks stippling, smoke, or soot.
Indicates a distance of 1 meter or more at the time of discharge.
Shored exit wounds – a bullet exit wound that has many
characteristics of a distant entrance wound. Caused by the
supporting or shoring the skin as the bullet exits.
Yawing – deviation of a bullet from the longitudinal axis of its flight.
Ethanol – ethyl alcohol or beverage alcohol found in beer, wine,
and liquors.
Depressant – drug that reduces excitability and calms a person
Stimulant – drug that produces a temporary increase of functional
activity or efficiency
Ventricular Fibrillation – uncoordinated non-propulsive quivering of
the heart often produced by heart attack; also by low voltage
electrocution.
Asphyxia – the interruption of oxygen to the brain.
Ligature – a device, similar to a tourniquet, usually of thread or
string, tied around a limb, blood vessel or similar to restrict blood
flow.
Introduction
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The purpose of
investigating a death
is to determine its
cause and manner.
 Forensic
pathologist
must be able to
support his/her
conclusions
Cause and Mechanism of Death
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1. The Cause of Death is the disease or injury
that initiated the lethal chain of events that led to
death.
 The
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2. The Mechanism of Death is a biochemical or
physiological abnormality produced by the cause
of death.
A
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underlying cause
contributory factor
3. Injury takes precedence over disease in
determining cause of death.
Manner of death
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4. The manner of death is defined as the
fashion in which the cause of death came
to be:
 Natural
(caused solely by disease)
 Accidental
 Homicide
 Suicide
} all involve trauma
Time of Death
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5. When a person dies the following can be used
to determine time of death:
mortis – stiffening of the muscles due to the
chemical reaction of glycogen (~4 hrs, lasts 24-36 hrs)
 Liver mortis – discoloration of the body due to the
settling of the red blood cells (w/in min.- becomes fixed in
 Rigor
12 hrs, disappears in 36)
mortis – is the cooling of the body (1.5°C per
hour for the first 8 hours at room temp)
 Algor
Classification of Traumatic Deaths
*Trauma- a body wound or shock produced by sudden physical injury,
as from violence or accident.
6. Traumatic deaths may be classified as:
 -Mechanical
 -Thermal
 -Chemical
Sharp
Blunt
Non-firearm
Low
Firearm
High
 -Electrical
7. Surgeons typically classify trauma as penetrating
(stab wound) or non-penetrating (collisions).
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8. Asphyxia, death caused by
interference of oxygen to the brain,
 can
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overlap all classes of traumatic deaths.
Ex: mechanical asphyxia – strangulation
Chemical asphyxia – cyanide poisoning
electrical asphyxia - electrocution
Mechanical Trauma
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1. Mechanical trauma occurs when applied physical force exceeds
the tensile strength of the tissue to which the force is applied.
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Sharp Force Injury
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Blunt Trauma
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Most common cause of death is damage to the brain
Produces lacerations, contusion, and hematomas
Firearm injury
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Injuries received from sharp implements (knives, swords, axes)
Produces incised wounds
Most common cause of death is exsanguination (bleed to death)
Most common suicidal and homicidal wounds in the US
Classified based on the type of firearm and the wounds
Other Blunt Force injury
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Motor vehicle collision, falls, (accidental)
Homicidal – lethal head injury
Incised wounds – Sharp force injury
Seen in this clay model is
the pattern of a stab
wound from a double
edge knife on the left and
a single edge knife on the
right.
This is a single-edge blade stab
wound in which there is a "hilt"
mark at the left. The sharp blade
edge is at the right. [Image
contributed by Todd Grey, MD,
University of Utah]
Blunt Trauma Wounds – Lacerations, Contusions, Hematomas
Here is a very superficial laceration of the
forehead. Note that the skin surface is broken.
There are some small tags of skin where the
surface was irregularly torn.
Firearm Wounds
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Types of Firearms
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Gunpowder propelled
(rare)
Smokeless powder
(nitrocellulose)
Handguns
Shotguns
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Types of wounds
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Diameter of the projectile or bullet
The velocity of the projectile
Penetrating (has and entrance
wound, but not exit)
Perforating (has an entrance and
an exit wound)
Proximity to the gun at time of
discharge
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Contact
Stippling
Distant wound
Shored exit wounds
Yawing
Firearm wounds
An abrasion ring, formed when the
force of the gases entering below
the skin blow the skin surface back
against the muzzle of the gun, is
seen here in this contact range
gunshot wound to the right temple.
[Image contributed by Todd Grey,
MD, University of Utah]
This is an contact gunshot entrance wound.
Since the barrel contacts the skin, the gases
released by the fired round go into the
subcutaneous tissue and cause the starshaped laceration. Note also the grey-black
discoloration from the soot, as well as the
faint abrasion ring. [Image contributed by
Todd Grey, MD, University of Utah]
This is a contact range
gunshot entrance wound with
grey-black discoloration from
the burned powder.
The right diagram illustrates the basic
differences between the skin appearance of
a contact, close (intermediate), and distant
(indeterminant) range gunshot wound. The
appearance of the wounding characteristics
in the skull is shown in the lower diagram in
which there is bevelling of the skull outward
away from the direction of origin of the bullet
This is an intermediate range gunshot
entrance wound in which there is powder
"tattooing" around the entrance site.
With a contact or very close range gunshot
wound, it is possible to have blood spatter as well
as sooting on the hand of the person firing the
weapon.
Chemical Trauma
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Deaths from trauma
include deaths that
result from the use of
drugs or poisons
The most common
drug – ethanol
 Longest
abuse
history of
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Alcohol..
 Nervous
system
depressant
 Slows reactions to the
brain
 At .25 gram percent /
go into coma
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Eventually breathe so
slowly they pass out
Other drugs of abuse….
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Barbiturates,
diazepams, and
opiates
 Produce
increasing
degrees of coma
followed by cessation
of breathing
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Exceptions:
– not
known to have
produces an overdose
death
 Cocaine – is a
stimulant and may
result in seizures, and
uncontrolled quivering
of the heart
 Marijuana
CO Poisoning
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Carbon Monoxide
 Odorless,
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colorless, explosive gas
Co kills by asphyxiation – cuts off
oxygen to the brain
Binds to the hemoglobin 300 times
more strongly than oxygen
Blood levels above 20% may prove
fatal
cherry red coloration
of skin
autopsy specimen showing brain
discoloration
Cyanide Poisoning
Interferes with the oxygenation of the brain
 Available as the sodium or potassium salt
that is used in electroplating and metal
polishing
 Smells like almonds
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Thermal Trauma
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Exposure to excessive heat or cold
 Hypothermia
 Hyperthermia
Diagnoses requires the absence of other
causes of death
 Thermal burns are localized wounds
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 Cause
death when complications arise
Electrical Trauma
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The passage of
electricity through a
person may cause
death when the heart
experiences
ventricular fibrillation
Asphyxias
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Drowning- death by
asphyxiation of water or
other liquid
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Fluid is in the lungs
Diatoms may also be
present
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Manual strangulation –
with the hands
Ligature strangulation –
with a rope/cord/wire
Most common findings
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fracture of the thyroid
cartilage
Hemorrhage of the neck
muscles
Presence of a furrow in the
neck
Petechial hemorrhaging