ForensicPathology

Medicolegal investigation of death

“The psychiatrist knows nothing and does nothing. The surgeon knows nothing and does everything. The pathologist knows everything… but is always a day too late.”

-TRADITIONAL MEDICAL MAXIM

Coroners vs. Medical Examiners

• Coroners- elected position, more often found in rural areas.

• Medical examiners- physician (usually a pathologist)

When are autopsies performed?

• Sudden and/or unexpected death• Public health concern (ex. Mysterious disease)• If someone dies unattended by a physician• Family asks for an autopsy• If an autopsy is not required by law, the next-of

kin must give permission• Laws vary from state to state.

Example

• Someone witnesses a suicide

• Know ID of person, time of death, cause of death.

• Why do an autopsy? – Show contributing factors to the suicide

• Terminal disease• Pregnancy• Drugs/alcohol

Example

• Someone observes a car accident in which someone else leaves the roadway, hits a tree and is killed instantly.

• The autopsy may reveal contributing factors:

• Blackout• Myocardial infarction• Alcohol/drugs

Parts of an autopsy

• External examination» Look for bruising, cuts, wounds, etc…

• Internal examination» Weigh organs» Check for abnormalities» Preserve in formaldehyde

• Microscopic examination» Histology – study of tissues

• Toxicology report» Blood, urine, bile, fluid from the eye» Looking for meds, drugs, alcohols, poison

Cause of Death

• What caused life to cease?• Ex. Blunt trauma to the head• Ex. Bullet to the heart• Ex. Heart attack• Ex. Kidney or liver failure• Ex. Cancer• Ex. Asphyxiation

• Long list

Manner of Death

1. Natural

2. Homicide

3. Suicide

4. Accident

5. Undetermined

Jobs of the ME

• 1. ID the deceased

• 2. Time/date of death

• 3. Cause/manner

• 4. Protect property of dead

• 5. Notify next of kin

Estimating Time of Death

• 1. Rigor mortis• 2. Livor mortis• 3. Algor mortis• 4. Stomach contents• 5. Vitreous humor• 6. Changes due to decomposition• 7. Entomology• 8. Botany

Rigor Mortistouch test

• Warm and not stiff: not more than a couple of hours

• Warm and stiff: dead between a couple of hours and a half day

• Cold and stiff: dead btw a half day and two days

• Cold and not stiff: dead more than two days

Rigor mortis

• ATP fuels muscle contraction- lack of ATP triggers rigor

• ATP breaks the link btw actin and myosin,

• ATP depleted after death, actin and myosin stay locked

• appears within 1-3 hour

Affects Rigor mortis

–Body temperature and environmental temp.

–Metabolic rate

–Starvation

–Physical activity

–Poison

Cadaveric spasm

• Body or body part “Frozen” in position at time of death

• Fast rigor due to lack of ATP– struggle or chase – Exercise – Shooting a gun– “Death grip” during drowning

Timeline of Rigor Mortis

• appears within 1-3 hours

0-12 hours: Body stiffens, starting with jaw, neck, face/fingers/toes, trunk, arms, and legs

12-24 hours: Entire body stays rigid

24-36 hours: Relaxation starting with jaw, neck, face/fingers/toes, trunk, arms, legs

Livor mortis

PML= postmortem lividity

- Purple coloring - Blood settles closest to the ground

- Appears within 30-60 min. of death

- No discoloration if • tight clothing • Object pressing against body

- Can tell if body has been moved since death

Problems with livor mortis

• Variations between races

• Blood loss

• Anemia

Other color changes

• Bluer color caused by being cyanotic (not enough O2)

– Can be caused by respiratory illness or cyanide poisoning

• Cherry red color- from carbon monoxide poisoning

Algor mortis

- Drop in body temperature after death.

- Avg. of 1-1.5 °F per hour

- Measure in liver/rectum

Algor Mortis affected by

»Location of body»Body size»Clothing»Weather»Temp @ death

ex. Fever from illness

ex. Elevated temp from drug use

ex. Head injury

Rigor, livor, algor

• Only useful for 24-48 hours

• Rigor- body relaxes

• Livor- becomes fixed

• Algor- body reaches ambient temperature

Stomach contents

• If food is in the stomach, the degree of breakdown of the food can help provide an estimate of time of death.

• 90% of what we eat is out of the stomach in 2-3 hours

Decomposition

• A) Autolysis- softening/liquefying of the body caused by enzymes released by cell organelles after death.

• B) Bacterial- breaks tissue into liquids/gases

Stages of Bacterial Decomposition

1. Initial Decay

2. Putrefaction

3. Black Putrefaction

4. Butyric Fermentation

5. Dry Decay

1. Initial Decay

• Initial Decay- externally OK, but internally decomposition starts.

• Discoloration of surface blood vessels in upper abdomen as bacteria spread.

• Color changes from red…dark red… purple…green

• 1st sign- green over right lower abdomen– cecum-pouch at start of large intestine

• E.Coli bacteria are normally found in the body but are kept in check by the immune system.

• After death, the bacteria are no longer held in check and multiply rapidly.

• E.Coli spreads from the intestines and enters the bloodstream.

• Bacteria form CO2 : gas causes bloating and eventually rupture of intestines.

2. Putrefaction

• Cadaver swollen w/ gases, odor of decay (within 2-3 days)

• Hair loosens

• Fluid from mouth and nose

Putrefaction

• Liver/brain—“swiss cheese” (from bubbling gases)

• Loose skin falls off

• Body swells, tongue/eyes protrude

• Breasts and genitalia balloon

3. Black Putrefaction

• Flesh is soft w/ black areas. Strong odor

4. Butyric fermentation cadaver drying out. – Some flesh. – Cheesy odor. – Ventral surface moldy.

• 5. Dry Decay

Vitreous humor

• Eye jelly dehydrates

• Potassium levels change

• Needle and syringe to suction the eye

Problems w/ vitreous humor

– K+ levels vary from front to back – Need every drop of vitreous humor—can

disrupt retina if pull to hard with syringe– Increased heat, humidity, fever… can falsely

raise K levels– Variation between 2 people or between

2 eyes of the same person

Entomology

• After death, flies lay eggs on the body.

• The eggs develop into larvae (maggots), and then pupa, and then adults.

• The time it takes to progress through each stage is predictable, and can be used to determine when the eggs were first laid and thus, when the victim died

Tasks

• 1. Preautopsy meeting

• 2. Photos

• 3. Reexamination• White light• UV• Laser• Alternate light source• Remove clothing, jewelry

Tasks

• 4. Fragile (trace) evidence• Fibers• Hairs• Glass• Debris

• 5. Vulnerable evidence collect saliva in bite marks

take control sample near bite mark

Tasks

• 6.Swabs• Vagina• Penis• Oral• Anal• Nasal

Tasks

• 7. x-rays• Broken bones• Metallic objects• Healed fractures• Dental x-rays

• 8. Gunshot residue

• 9. Scrape fingernails

Tasks

• 10. Wounds

• 11. Pubic Hair combing

• 12. Collect standard hairs• Pulled from head• Need 50-100 hairs

• 13. Casts• Make 3-D casts of bite marks, entrance holes, cuts

Tasks

• 14. ID photos• Face, tattoos, scars

• 15. Fingerprints

• 16. Autopsy• A. Injection sites, look in orifices• B. Y shaped incision• C. Inspect organs

» heart., lungs, liver, kidneys

Autopsies

“This is the place where death rejoices to teach those who live.”