The Medical Examiner

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The Medical Examiner
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The Medical Examiner
The Medical Examiner Vs. The Coroner
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The Medical Examiner
The Medical Examiner is a medically qualified
government officer whose duty is to investigate
deaths and injuries that occur under unusual or
suspicious circumstances, and to perform
post-mortem examinations.
The Medical Examiner is required to have a
medical degree, often with additional education
in forensic pathology.
Typically, The Medical Examiner is appointed to
his/her position.
The Medical Examiners task is to determine
cause, time and manner of death.
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The Medical Examiner
The Coroner are often elected (rather than
appointed) officials, and usually do not need to
hold any medical qualification.
As finders of facts, they use Medical Doctors to
determine cause, time and manner of death.
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The Medical Examiner
What are some of the questions a M.E. is asked to
answer?

1. The reason someone dies is called Cause of Death.

Ex. Heart attack, disease, stroke, physical
injury.
2) The way someone dies is called Manner of Death.

1. Natural Causes

b. Accidental Death
c. Suicide
d. Homicide
e. Unknown
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The Medical Examiner
3) Identification
In some cases it is not obvious who the victim
is. It is the M.E. job to I.D. the victim.
The M.E. will use many of the following to
determine I.D.
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The Medical Examiner
Dental Impressions
DNA
Skeletal Remains
Can you think of any other means of
identification?
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The Medical Examiner
4) Time of Death
During an autopsy, the M.E. wants to determine
when the person died.
By establishing time of death, a suspect may be
proven innocent simply because he/she was not in
the place as the victim at the time of death.
On the other hand, a suspect my remain a person
of Interest if he/she was in the same area at the
time of death.
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The Medical Examiner
How is the time of Death Established?
1) Livor Mortis
Death Color
When the heart stops beating blood will settle or
pool in the lowest parts of the body.
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The Medical Examiner
Pooling of blood in the body, known as lividity,
will provide clues to how long the person has
been dead.
Determining time of Death with the use of
Lividity.

• Lividity begins to show about two hours after
  death.

• Discoloration is permanent after about eight
  hours.

• Between two and eight hours, if the skin is
  pressed,
• the color will disappear.

• After eight hours, if the skin is pressed, the
  color will
• remain.

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The Medical Examiner
Besides Time of Death, lividity can provide other
clues.
Because gravity pulls blood toward the ground,
livididty can reveal the position of the body at
the time of death.
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The Medical Examiner
2) Rigor Mortis
Death Stiffness
Rigor Mortis is the temporary stiffness of the
body after death.
Determining time of Death with the use of Rigor
Mortis.

• Rigor Mortis starts about two hours after death.

• Rigor Mortis starts at the head and works its way
  to the legs.

• After 12 hours the body is at it stiffest state.

• Generally, stiffness gradually disappears after
  36 - 48 hours.

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The Medical Examiner

• Suppose a detective comes to a crime scene and
  the
• victims body is not in rigor. What is the time
  of death?

Answer Less than 2 hours or more than 36-48
hours.

• Suppose a detective comes to a crime scene and
  the
• victims body is in full rigor. What is the time
  of death?

Answer Around 12 hours.
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The Medical Examiner
3) Algor Mortis
Death Heat
Algor Mortis is the cooling of the body after
death.
Determining time of Death with the use of Algor
Mortis.
Determining time of death using the cooling of
the body (taken from the liver) is sometimes
difficult.
Many factors contribute to how the body cools.
Such as

• Environment Temp

• Victims clothes, if any

• Victims Weight

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The Medical Examiner
Determining time of Death with the use of Algor
Mortis.
0 12 hr after death
12 ? hr after death
Body loses 1.4 F per hr
Body loses .7 F per hr
These values are just estimates and my vary
depending upon many other factors.
We can average these values and use 1 F per hour.
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The Medical Examiner

• During an autopsy the liver temperature is
  determined
• to by 92.6 F. Approximately how long has the
  body been
• dead?

98.6 F 92.6 F 6 F
Answer Since the body cools at a rate of 1 F, 6
hrs.
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The Medical Examiner
4) Stomach Contents

• In general it takes four to six hours for the
  stomach to
• empty its contents into the small intestines.

• It then takes another 12 hours for the food to
  leave
• the small intestine.

• It takes about 24 hours for food to complete the
• the digestion cycle.

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The Medical Examiner
From this information it can be concluded that

• If undigested food is present in the stomach,
  then
• death occurred zero to two hours after the last
  meal.

2) If the stomach is empty but food is found in
the small intestine then death occurred at least
four to six hours after a meal.
3) If the small intestine is empty but food is
found in the large intestine, death occurred 12
hours or more after a meal.
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The Medical Examiner
5) Decomposition
A corpse decomposes in predictable ways over time
that can help determine time of death.
Within two days after death

• Cell autolysis (self digestion) begins

• Skin turns green/purple from blood decomposition

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The Medical Examiner
After four days

• Skin starts to blister

• The abdomen swells with gas released from
  bacteria
• in the intestines.

Within six to ten days

• The build up of gases cause chest and abdomen to
• burst.

• Fluids begin to leak from the body openings.

• Tissues begin to liquefy.

• The skin sloughs off the body.

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The Medical Examiner
6) Insects
The presence of insects on a body can provide
detailed information about the Time of Death.
In fact, insects are so useful in crime scene
investigation That there is an entire field
dedicated to this study and Practice and it is
called Forensic Entomology.
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The Medical Examiner
Within minutes of death, certain insect arrive to
lay their eggs on the body.
For example, blowflies lay their eggs which soon
turn into larva. The larva feed on the
decomposing flesh.
Sometime after, wasps lay their larva on the body
which feed on the blowfly larva.
In addition, each stage of decomposition attracts
different insects.
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The Medical Examiner
Lets look at the Blowfly and how it can help us
determine Time of Death.
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The Medical Examiner
Similar to other insects, blowflies exhibit
different stages of development
Eggs
Larva
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The Medical Examiner
Pupae
Adult
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The Medical Examiner
Because we know how long it takes for the various
stages of development, forensic entomologists can
determine when the blowflies arrived by studying
the insects on the corpse.
If we know when they arrived we can determine
approximate time of death.
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The Medical Examiner
Blowfly Life Cycle
Stage Size (mm) When first appears Phase Duration Characteristics
Egg 2 Soon after death 8 hrs Found in moist areas
Larva 5 2 5 days 20 56 hrs Black mouth visible
Pupae 10-17 8 20 days 4 12 days Immobile
Adult Varies 21 24 days Several Weeks Flight possible
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The Medical Examiner
If a corpse contains blowfly eggs approximate
time of death is?
Answer Less then 24 hrs
If a corpse contains blowfly larva approximate
time of death is?
Answer Between 2 and 5 days.
If a corpse contains blowfly pupae approximate
time of death is?
Answer Between 18 and 24 days.