forensic pathology and autopsy

FORENSIC PATHOLOGY AND AUTOPSY

Pathology Field of Medicine concerned with

identifying disease Forensic Pathology – subspecialty of

pathology concerned with identification of human remains and determination of the cause and manner of death

The Field that performs an after death investigation of sudden or unexpected death or injury

What Do They See Deaths with violence – accidents,

suicides, homicides Suspicious Deaths Sudden, unexpected deaths, Deaths without a physician in attendance Deaths in a prison or jail

Goals Identify:

Cause – The event/ injury that starts the process towards death

Manner - Mechanism – the normal body function that

results in death Whether Time of death is consistent with

proposed time

Definition of Death Formerly not a problem End of heart and/or lung function

No oxygen or blood = no life Brain death

Individuals may be kept alive by artificial means through machines that breathe as lungs would or that pump as a heart would

Cause of Death The process that starts the chain of

events leading to death Atherosclerosis Heart Attack GSW to Chest infection of lungs Car Accident death during surgery 10 years

later Blunt Force injury to head not swallowing

correctly Choke

Manner of Death Natural Accident Suicide Homicide Undetermined

Natural Deaths Atherosclerosis Pneumonia Cancer Long term Alcohol/Drug abuse

Accident Car Accident Alcohol/ Drug overdose Drowning Suffocation

Homicide/Suicide GSW Stab Wound Drug Overdose Drowning Car Accident Asphyxia

Undetermined Not enough information about

circumstances surrounding death Drug overdose – accidental overmedication or

suicide Cause of death unknown

Skeletonized remains No anatomical or toxicological explanation

Scene investigationMedical and legal conclusions rely on thorough scene investigation

Identity Approximate time of death Evidence and clues to circumstances

around death Was the house locked? Were there signs of struggle Position of body Suicide notes

Identification of remains Visual by family/friends Location of body – in their home? ID – driver’s license, distinctive feature –

tattoo Comparing x-rays Dental Records DNA Fingerprints

Mechanism of Death The immediate activity that results in

death. Hemorrhage Widespread infection Heart Attack

Time of Death Important for time of the murder,

eliminate or suggest suspects, confirm or disprove alibi

Most methods are to a degree unreliable and inaccurate.

The longer the time between death and the attempt to estimate the time of death, the less precise the estimate of the interval

Estimation methods Body temperature – 98.6 – rectal temp

/1.5 Insect action Stomach contents – stage of digestion Last known activity – newspaper/ mail,

phone conversation/ text

Livor and Rigor Livor Mortis is a reddish/ purple coloration due

to accumulation of blood in the small vessels of the gravity dependent areas. Occurs 30 min to 2 h after death Fixed at 8-12 h Important to determine position of body

Rigor – stiffening of the body due to disappearance of muscle energy Usually appears 2-4h after death, fully develops 6-

12 h after death Classically

Jaw arms -> legs

Time of Death Body Temperature

Time since death = (98.6°F – Rectal Temp) / 1.5 Based on assumption body temp is normal at death

Decomposition (Decomp) Breakdown of Cells and Organs by chemical process Breakdown by bacteria and fermentation

1. Green discoloration of abdomen (24-36h)2. Green spreads to head, neck and shoulders3. Swelling of the face and abdomen due to gas formation4. Marbling – breakdown of blood gives green/black color of blood

vessels5. Generalized bloating (60-72 h)6. Skin slippage7. Dry/ skeleton phase – 2 weeks in hot humid temps, months in

snow

Entomology Different insects are attracted at different

stages after death Flies are the most common form of insect

associated with dead bodies Lay eggs in orifices and open wounds Eggs generally are deposited immediately

after death in the day time Only eggs on the body = 1-2 days Maggots grow excessively larger in different

stages each about 1 day Adult flies emerge at 12 -18 days

External Exam General Size and Appearance Clothing /personal belongings Major Injuries – cause of death signs Medical Intervention Signs of struggle – Frenulum, broken bones,

scratches around the hands Bruises, cuts, petechiae Scars, tattoos Livor, Rigor Teeth, eyes, hair Blood, eye fluid, urine

Trauma to the Human Body

1. Determine type of wound

2. Measure the dimensions (length, width, depth)

3. Position relative to anatomical landmarks

4. Determine initial location if wound involves cutting, slashing, etc.

5. Determine height from heel

Types of Wounds 1. Lacerations

2. Incised Wound

3. Puncture

4. Abrasion

5. Contusion

6. Gunshot

Lacerations

Incised Wounds Slash Stab

Puncture – penetrating injury due to an object with no blade

Abrasions

ContusionsColor changes 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)

Assumes person is healthy.

Gunshot Wounds

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

Gunshot Wounds

Starring of a contact wound – barrel touching the skin

Stippling – powder burns on the skin when the gun is inches to a few feet from the victim

Autopsy

Y incision

Internal Exam Y Shaped insicision Remove Sternum Exam any signs of injury internally

(gunshot hole, stab wound) Exam for signs of blood inside

Organs Exam each organ, weigh them, cut them

open, take pieces for microscope exam

Heart Lungs Kidneys Liver Spleen Bladder Brain

Natural Deaths Heart Attack

Gunshot Wounds Contact

Muzzle imprint, star-like cuts if close to bone, gunpowder and soot enter wound

Close Range Increased diameter of soot of tattooing around wound Particles of gunpowder around wound, soot on skin, tattooing

of skin Intermediate

Up to 3 feet Increase in diameter again of particles and stippling, no soot

Long Range No gunpowder, soot, tattoing Difficult to determine distance –6 feet not different from 16

feet

GSW Entrance Wounds

Usually smaller than exit wounds May have star-like appearance Inward beveling of skull Ring of gunpowder and stippling

Exit wounds Usually larger than entrance due to deflection

by tissue Outward beveling No gunpowder, soot or skin injury

Asphyxia Anything that interferes with oxygen

uptake or utilization Suffocation

Failure of oxygen to reach blood Choking, drowning, carbon monoxide poisoing Compression of chest – heavy objects

Strangulation Usually cuts off blood supply to brain, not cutting

off air.

Burns Death due to smoke inhalation,

incineration or infection Establish – ID, whether the victim was

alive at the time of fire Cause of death Manner of death 75% of fire related deaths due to

inhalation of toxic smoke – carbon monoxide, cyanide

Electrocution Low voltage

Burns present at entry and exit sites Death due to heart attack

High Voltage Electrical burns Charring Death due to hearth attack or paralysis of

breathing muscles

Blunt force injury to head Brain Contusion – coup occurs at site of

blow to head Bleeding under skull and into brain Tearing of arteries and veins that supply

the brain May kill immediately, or have slow

growth of blood in the brain that compresses brain and prevents brain function

Car Accident Patterned abrasions / bruises from

steering wheel and seatbelt Damage to liver and spleen