Forensic Pathology

Students Will Be Able To:• Discuss the definition of death.• Distinguish between four manners of

death: natural, accidental, suicidal, and homicidal.

• Distinguish between cause, manner, and mechanisms of death.

Death• Is the cessation of end of life

• Irreversible cessation of circulation of blood

• Irreversible cessation of all brain activity

Death• First stage of death is stoppage

• Heart stops beating• Cells die because of no oxygen

• Known as autolysis• Cells breakdown resulting in cell

membrane dissolving and cell contents spilling out

• Nerves, muscles, organs, and brain stop working

Forensic Pathologist• AKA medical examiner• Is a medical doctor• Works for the county or state

Job Duties• A medical examiner has 5 job duties

• Identify the decedent• Determine the manner of death• Determine cause of death• Determine the mechanism of death• Determine time of death

• Manner, cause, mechanism, and time of death determined during autopsy

Identification of the Decedent• To facilitate identification of a corpse, the

following procedures are standard:• Physical Description • Scars and Marks• Fingerprints• Photographs• Age Determination—use of teeth for rough

estimate• Dental Features• Radiological Evidence• Blood factors• Medical Indications• Other means

Manner of Death• Is the way that a person dies• There are five manners of death

• Natural• Accidental• Homicidal• Suicidal• Undetermined

• Autopsy findings are critical in determining the intent or mode of death

Natural Death• Death by natural cause is a term used

by coroners to describe the death of someone by occurring disease process, or is not apparent given medical history or circumstances

• The majority of natural death is caused by old age

• Other causes of natural death are heart disease, stroke, genetic disorders, etc.

Accidental Death• Accidental death is a death that is often

caused by mistake or in a freak occurrence

• These deaths are not planned yet can be explained by surrounding circumstances

Homicide• The term ‘homicide’ refers to the act of

killing another person• Homicide is often the most investigated

death, therefore making it the most autopsied

Suicide• The act of ending ones own life • These autopsies often easily identify

source, cause, and other factors of the death

• Suicide is often identified in the forensic autopsy as a cause of toxic, firearms, blunt force trauma, etc

Undetermined Death• In some jurisdictions, the

Undetermined category may include deaths in absentia, such as deaths at sea and missing persons declared dead in a court of law; in others, such deaths are classified under "Other"

Manner of Death• Consider the following two examples.

How would you categorize the manner of death?• A man with a heart condition is

attacked and dies from a heart attack during the assault. Is the manner of death accident or homicide?

• An elderly woman dies after being kept from receiving proper health care by her son. Is the manner of death natural or homicide?

Cause of Death• The pathological condition that

produced death• Ex: bludgeoning, shooting, burning,

drowning, strangulation, suffocation, hanging, drowning

Mechanism of Death• Describes the specific change in the

body that brought about the cessation of life• Ex: loss of blood, exsanguination,

cessation of brain function

Students Will Be Able To:• Explain how the development of rigor,

algor, and livor mortis occurs following death.

• Use evidence of rigor, algor, and livor mortis to calculate the approximate time of death.

• Use evidence from the autopsy’s report on stomach contents to estimate time of death.

Time of Death• Generally, time of death is estimated

from certain changes that occur in the body following death

• Changes can also indicate alterations in the body’s position after death and whether or not the death was murder or suicide

Time of Death• Can use the following to estimate time

of death• Liver mortis• Rigor mortis• Algor mortis• Stomach content• Ocular changes

Livor Mortis• Means death color• As the body decomposes, blood seeps through

tissues and settles in the lower parts of the body

• RBC’s break down causing hemoglobin to spill out• Hemoglobin turns purple when autolysis

occurs• Dark purplish-blue discoloration that is seen

on the portions of the body nearest the ground is called postmortem lividity

Livor Mortis• Provide clues as to how long a person has

been dead• Lividity begins 2 hours after death• After 8 hours, lividity is fixed

• Discoloration becomes permanent• If death occurred between 2 and 8 hours,

lividity will be present but when the skin is pressed, the color will disappear

• Also provides a clue as to what position a person was in when they died• Lets CSI’s know if the body has been moved

Livor Mortis• Ambient temperature at which a person

dies impacts the time it takes for lividity to set in• If outside on a hot day, livor mortis

occurs at a faster rate• If in a cool place, livor mortis occurs

at a slower rate• Also affected by anything impeding

blood flow such as watches, rings, belts, etc

Rigor Mortis• Immediately after death the body is limp due

to relaxation of the muscles• Over time the muscles begin to stiffen due to

chemical changes within the muscle tissue—this is called rigor mortis• Calcium accumulates in the muscle tissue

resulting in muscle fibers remaining in a contracted, rigid position

• Rigor begins at the lower jaw and neck and spreads downward

Rigor Mortis• Starts within 2 hours after death

• Starts in head• After 12 hours, the body is at its most

rigid state• Stiffness disappears after 36 hours

• Can last as long as 48 hours• Depends on body weight and

temperature

Rigor Mortis• No visible rigor entails that the

individual has been dead less than 2 hours

• If body is rigid, then the body has been dead 12 hours

• If rigor is only in head, then the person has been dead a little over 2 hours

• If there is rigor throughout the body but not in the face, then the body is losing rigor resulting in the individual being dead over 15 hours

Rigor Mortis• Factors affecting rigor mortis include

• Ambient temperature• Cooler the body, the slower the onset of rigor• Warmer the body, the faster the onset of rigor

• Person’s weight• Rigor is slower in a heavier person than in a

thinner person• Due to stored oxygen

• Type of clothing• Presence of clothes accelerates rigor mortis• Naked body cools faster which slows down

rigor

Rigor Mortis• Factors affecting rigor mortis include

• Illness• If a person dies with a fever, the body

temperature will be higher and rigor will set in faster

• Level of physical activity before death• If a person was exercising before death,

then rigor will progress faster• Sun exposure

• A body exposed to direct sunlight will be warmer resulting in rigor to occur faster

Algor Mortis• Defined as death heat• Describes the temperature loss in a

corpse• Normal temp is 98.6 F• After death body tends to cool• Generally, temp of a dead body

averages a drop of approx. 1.5 degrees F per hour.

Algor Mortis• To determine the temperature of a

corpse, a thermometer is inserted into the liver

• Generally, temperature of a dead body averages a drop of approx. 0.78°C (1.4°F)

• After 12 hours the body loses about 0.39°C (0.7°F) per hour until the body reaches the same temperature as the surroundings

Algor Mortis• Factors affecting algor mortis

• Surrounding temperature• Body will lose heat faster in a cooler

environment that in a warmer environment• Surrounding air temperature

• Heat loss will occur faster in a windy environment

• Weight of individual• Excess body fat will slow down algor mortis

• Clothing• Presence of clothes will slow down algor

mortis

Stomach Content• Time of death can be approximated by

appearance and amount of stomach contents

• It takes 4-6 hours for the stomach to empty its contents in the small intestine and another 12 hours for the food to leave the small intestine

Stomach Content• If undigested stomach contents are

present, then death occurred 0-2 hours after last meal

• If the stomach is empty, but food is found in the small intestine then death occurred at least 4-6 hours after a meal

• If the small intestine is empty and wastes are found in the large intestine, then death occurred >12 hours after a meal

Ocular Changes• Early postmortem changes occur in the eyes• Buildup of potassium accumulates inside of

vitreous humor of eye• Buildup can be used to estimate the time of

death• If the eyes stay open, a thin film may form on

the corneal surface in a few minutes, and cloudiness in two to three hours

• If the eyes remain closed, corneal film may not occur for hours, and cloudiness may take 24 hrs or longer to appear

Students Will Be Able To:• Describe the stages of decomposition of

a corpse.

Decomposition• Within 2 days after death

• Cell autolysis begins• Green and purplish staining occurs

from blood decomposition• The skin takes on a marbled

appearance• The face becomes discolored

Decomposition• After 4 days

• The skin blisters• The abdomen swells with the gas

carbon dioxide that is released by bacteria living in the intestines

Decomposition• Within 6-10 days

• The corpse bloats with carbon dioxide as bacteria feed on tissues• Eventually the gas causes the

chest and abdominal cavities to burst and collapse

• Fluids begin to leak from the body openings as cell membranes rupture

• Eyeballs and other tissues liquefy• The skin sloughs off

Decomposition• Factors affecting decomposition

• Person’s age• Clothing on body

• Naked bodies decompose faster than clothed bodies

• Size of the body• The fat and fluids in overweight

individuals break down faster than people of normal weight

Decomposition• Factors affecting decomposition

• Environment• Bodies will decompose faster in a

warm environment• Bodies decompose faster in air • Bodies decompose slower in

water or if buried• Nature of death

• Sick individuals decompose faster than healthy individuals

Stages of Decomposition• 5 stages of decomposition

• Initial decay• Corpse appears normal on the outside,

but is starting to decompose from the actions of bacteria and autolysis

• Putrefaction• Odor of decaying flesh is present and

the corpse appears swollen• Black putrefaction

• Very strong odor• Parts of the flesh appear black• Gases escape and the corpse collapses

Stages of Decomposition• 5 stages of decomposition

• 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 from

lack of moisture

Students Will Be Able To:• Explain the significance of an autopsy.• Describe the steps of an external

examination of the body.• Describe the steps of an internal

examination of the body. • Explain the importance of filling out

paperwork completely during an autopsy.

Autopsy• Preliminary examination

• Conducted in deaths of criminal violence, suicide, accidental deaths, deaths where no physician was present, sudden deaths, prison deaths, and deaths that are suspicious or unusual

• If preliminary examination fails to reveal a clear cause of death—an autopsy is conducted

Autopsy Protocol• The corpse is brought to the medical

examiner’s office in a brand new body bag (to avoid transfer of evidence between cases) or in a set of evidence sheets

• The body is then placed on the cadaver dissection table

Physical Examination• The physical examination of the body is broken

up into two parts• External Examination

• The external examination consists of inspecting the physical outer layer of the body for signs of foul play that would result in injury or death

• Internal Examination• The internal examination consists of

inspecting the internal organs of the body for evidence of trauma or other indications of the cause of death

External Examination• Steps of an external examination• Photographed• Physical evidence collected off body• Samples of hair, nails, etc. are collected• Undressed, examined for wounds• Lacerations, abrasions, bruises

• Measured, weighed, cleaned

Internal Examination• Steps of an internal examination

• Incisions• A “Y” shaped cut from behind

each ear and running down the neck, meeting at the breastbone, continuing towards the groin• Most often used in cases of

suspected strangulation

Internal Examination• Steps of an internal examination

• Incisions• A “T” shaped cut from each

shoulder, meeting at the breastbone, continuing towards the groin.• Used to create a better

looking finished product as this cut is not often seen

• Single vertical cut from throat to groin

• All cuts deviate towards the left

Internal Examination• Cuts

• The chest cavity is cut open using shears

• The ribs are sawed away, letting them be lifted off the body, exposing the heart and lungs

• Removal• All organs are removed

• All removed organs are now weighed and examined for unusual markings or signs

Internal Examination• Brain examination

• An incision is made from a point behind one ear, over the top of the head, to a point behind the opposite ear

• The scalp is pulled away from the skull, creating tow flaps

• The front flap goes over the face, the rear flap over the neck

• The skull is then cut with an electric saw to create a cover that can be pulled off to expose the brain

• The brain is then cut from the spinal cord and lifted out of the skull for further examination

Internal Examination

• The cardiovascular system, the respiratory system, the central nervous system, and all other “systems” in the body that help control activity are examined

Paperwork

• After an autopsy, the medical examiner must fill out paperwork on the deceased and complete a legal death certificate