The Medical Examiner

The Medical Examiner

The Medical Examiner

Vs.

The Coroner

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 Examiner’s task is to determine cause, time and manner of death.

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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What are some of the questions a M.E. is asked to answer?

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

2) The way someone dies is called Manner of Death.

Ex. Heart attack, disease, stroke, physical injury.

a. Natural Causes

b. Accidental Death

c. Suicided. Homicide

e. Unknown

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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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Dental Impressions DNA

Skeletal Remains

Can you think of any other meansof identification?

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4) Time of Death

During an autopsy, the M.E. wants to determine when theperson died.

By establishing time of death, a suspect may be proveninnocent simply because he/she was not in the same place as the victim at the time of death.

On the other hand, a suspect may remain a person ofinterest if he/she was in the same area at the time of death.

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How is the time of Death Established?

1) Livor Mortis = Death ColorWhen the heart stops beating blood will settle or pool in the lowest parts of the body.

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Pooling of blood in the body, known as lividity, willprovide 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 willremain.

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Besides Time of Death, lividity can provide other clues.

Because gravity pulls blood toward the ground, livididtycan reveal the position of the body at the time of death.

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2) Rigor Mortis = Death Stiffness

Rigor Mortis is the temporary stiffness of the body afterdeath.

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

Answer: Around 12 hours.

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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• Victim’s clothes, if any• Victim’s Weight

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Determining time of Death with the use of Algor Mortis.

0 – 12 hr after death

Body loses 1.4° F per hr

12 – ? hr after death

Body loses .7° F per hr

These values are just estimates and my vary dependingupon many other factors.

We can average these values and use 1° F per hour.

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• During an autopsy the liver temperature is determinedto be 92.6° F. Approximately how long has the body beendead?

Answer: Since the body cools at a rate of 1° F, 6 hrs.

98.6° F – 92.6° F = 6° F

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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 leavethe small intestine.

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

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From this information it can be concluded that:

1) If undigested food is present in the stomach, thendeath occurred zero to two hours after the last meal.

2) If the stomach is empty but food is found in the smallintestine then death occurred at least four to six hoursafter a meal.

3) If the small intestine is empty but food is found in thelarge intestine, death occurred 12 hours or more after ameal.

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5) Decomposition

A corpse decomposes in predictable ways over time thatcan 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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After four days:

• Skin starts to blister• The abdomen swells with gas released from bacteriain the intestines.

Within six to ten days:• The build up of gases cause chest and abdomen toburst.

• Fluids begin to leak from the body openings.

• Eyeballs and tissues begin to liquefy.

• The skin sloughs off the body.

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6) Insects

The presence of insects on a body can provide detailedinformation about the Time of Death.

In fact, insects are so useful in crime scene investigationThat there is an entire field dedicated to this study andPractice and it is called Forensic Entomology.

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Within minutes of death, certain insect arrive to lay theireggs on the body.

For example, blowflies lay their eggs which soon turn intolarva. The larva feed on the decomposing flesh.

Sometime after, wasps lay their larva on the body whichfeed on the blowfly larva.

In addition, each stage of decomposition attracts different insects.

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Let’s look at the Blowfly and how it can help us determineTime of Death.

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Similar to other insects, blowflies exhibit different stagesof development:

Eggs Larva

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Pupae Adult

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Because we know how long it takes for the various stagesof development, forensic entomologists can determinewhen the blowflies arrived by studying the insects on thecorpse.

If we know when they arrived we can determine approximatetime of death.

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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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If a corpse contains blowfly eggs approximate time ofdeath is?

Answer: Less then 24 hrs

If a corpse contains blowfly larva approximate time ofdeath is?

Answer: Between 2 and 5 days.

If a corpse contains blowfly pupae approximate time ofdeath is?

Answer: Between 18 and 24 days.