Autopsy

Forensic Pathology

What is an Autopsy?

• Postmortem examination of the organs and tissues of a body to determine cause of death or pathological conditions.

• Includes the dissection of a corpse.

Type of Autopsies

• Medical• Forensic• Private

Why do an Autopsy?

• Primary reason is to determine cause of death, there are other benefits to individual families, the practice of medicine, and the community at large.

Benefits of an Autopsy• Allaying a family’s fears about

what they could have done to prevent the death.

• Providing family members information about potential genetic diseases that may have implications for them.

• Medical education, training and research leading to improved health care.

• Providing information about preventable causes of disease and accident and other public health hazards.

Forensic Benefits of an Autopsy

• Investigation of homicide, suspected homicide, other unexplained or suspicious deaths, and deaths apparently due to accident or injury.

Forensic Pathologist

• Also called medical examiners or coroners.

Role of the Forensic Pathologist

4 broad determinations are to be made by the pathologist:A. Cause of Death – medical diagnosis denoting disease or

injuryB. Mechanism of Death – altered physiology by which

disease/injury produces death (arrhythmia, exsanguination)

C. Manner of Death– 1. Homicide 2. Suicide 3. Accidental 4. Natural Causes 5.

Unknown

D. Time of Death

Cause & Mechanism of Death

• Asphyxiation– Strangulation– Drowning– Fire victim

• Exsanguination– Major blood loss

• Blunt force trauma• Sharp force trauma• Chemical trauma

Manner of Death-Natural• Natural: 80 year old dies of

congestive heart failure.– Natural deaths are the cause of the

majority of deaths that occur.• The manners of death in this

category include:– heart failure,– disease, and– death during sleep etc. The autopsy

reveals certain aspects of the death, whether it occurred suddenly, unexpectedly or if the person was critically ill and hadn't seen a doctor in the last two weeks.

Manner of Death

• Homicide-death caused by another person• Suicide-death inflicted upon self• Accidental-unintentional and without malice,

group swimming and one drowns• Unknown/Undetermined-absolute cause not

able to be determined

Estimating the time of death

• An accurate assessment is of great importance to police in narrowing down the list of suspects.– It can allow police to pinpoint the time during

which they need to find out what the suspects were doing and allows them to eliminate people who have an alibi for that period from there enquiries.

Can estimate time of death from • body temperature (algor mortis)• insect action (forensic entomology)• stomach contents (stage of digestion)• last known activity (last sighting, newspaper/mail)• normal postmortem changes– rigor mortis (Hours)– livor mortis/lividity (Hours)– Desiccation – Putrefaction (days 4-10)– cell autolysis (also called butyric fermentation) (days

10-20)– dry decay (days 20-50)

Estimating Body Temperature

• A healthy human body temperature is approximately 37°C (98.6°F) .

• Upon death, the body temperature begins to fall at a constant rate about 1.5°F every hour until it reaches the ambient temperature,(temperature of the area surrounding the body).– This postmortem cooling of the body is called algor mortis.

• The most accurate measurement of core body temperature is taken by inserting a thermometer into the liver.

• At the death scene, death investigators sometimes measure body temperature rectally. (less reliable but significantly more convenient).

Estimating Body Temperature• Assuming that the body temperature was normal at the

time of death, the following formulas can be used to estimate the time of death within the first 12 hours:

• Time since death (in hours)= 37°C − Current body temperature OR 0.78

In the first 12 hours:• head, arms, and legs cool rapidly. • body temperature will drop 9.4°C

The following formula would be used if the victim died more than 12 hours before the body was found:

If the body temperature is below 27.6°C, then the victim has been dead for more than 12 hours

Estimating Time of Death

• Autopsy: medical dissection and examination of a body in order to determine the cause of death

• Rigor Mortis: medical condition that occurs after death and results in the shortening of muscle tissue and the stiffening of body parts in the position they are in when death occurs. Occurs within 24 hours and gone within 36 hours

Estimating Time of Death

• Livor Mortis or lividity: medical condition that occurs after death and results in the settling of blood in areas of the body closest to the ground. Begins immediately after death and lasts for 12 hours

• Algor Mortis: postmortem changes that cause a body to lose heat. Process in which the body continues to cool to room temperature. 1 – 1.5 degree/hour

Body temperature

• Following death, the body begins to cool at a rate which depends on a range of factors.– A naked body will cool faster than a clothed one;– A large adult will cool slower than that of an

infant;– A body in a prone spread-eagled position will cool

faster than a body slumped in the corner;– A body exposed to air currents will cool faster

than one in a protected area.

Evidence to be Collected at Autopsy

• Victim’s clothing• Fingernail scrapings• Head and pubic hairs• Blood (for DNA typing)• Vaginal, anal, and oral swaps (sex-crimes)• Recovered bullets/knives from body• Hand swabs from shooting victims (for GSR

analysis)

Trauma to the Human BodyRole of the Pathologist

1. Determine type of wound2. Measure the dimensions (length, width,

depth)3. Position relative to anatomical landmarks4. Determine initial location if wound involves

cutting, slashing, etc.5. Determine height from heel

Types of Wounds (Trauma)

1. Lacerations2. Incised Wound3. Puncture4. Abrasion5. Contusion6. Gunshot

Abrasions

ContusionsAssuming the victim was healthy, color changes a contusion or a bruise goes through can give rough estimate of time of injury:• Dark blue/purple (1-18 hours)•Blue/brown (~1 to 2days)•Green (~ 2 to 3 days)•Yellow (~3 to 7 days)

Gunshot WoundsThings for pathologist to learn:• type of firearm• distance of gun to victim• entrance vs exit wounds• track of projectile

Gunshot Wounds

Stippling – powder burns on the skin when the gun is inches to a few feet from the Victim Starring of a contact

wound – barrel touching the skin

Autopsy-Steps Involved:

1. External Examination– measurements - length, weight– inspection of external surface for injury,

discoloration, “cause of death” signs

Autopsy-Steps Involved:2. Opening of Trunka. ‘Y’ incisionb. Open rib cagec. Condition of heartd. Remove organs

Autopsy

2d. Remove Organs:• must cut ligaments holding organs in the body cavity

and through the trachea and rectum• transfer organ block to a dissecting table• examine organs in proper order (weigh, physical exam in

and out, take tissue samples, save other appropriate samples)– Heartliverspleenkidneyspancreasbladder genitalia complete G.I. tract

– save postage stamp sized amount of tissue– examine tissue under a microscope for bacteria,disease

Autopsy-Steps Involved:

• 3. Remove brain cut around cranium using “Stryker saw” store for 2 weeks in 10% formaldehyde

• 4. Closing