Forensic Pathology

44 BCE

Antistius - A Roman physician performs an autopsy on Julius Caesar

Where does the term “forensic” come from?

The autopsy report on Julius Caesar’s death gave rise to the term in Latin, which means “before the forum”

1200s

Investigation systems develop including coroners, medical practitioners and death investigators.

Develop in England, Europe, and Asia

1248 CE

The first textbook of legal medicine is published by Xi Yuan Ji Lu

“The Washing Away of Wrongs”

1482

Pope Sixtus IV allows local bishops to give bodies of executed criminals and unidentified corpses for dissection

1598

De Relationibus Medicorum - Fortunatus Fidelis is the first to practice modern Forensic Medicine and testify to his findings

1621

Quaestiones Medico-Legales - Paulo Zacchias the “Father of Legal Medicine”

1918

First modern medical examiner office in NYC

ABMDI

American Board of Medicolegal Death Investigation

Pathology

The study and diagnosis of disease

Anatomical Pathology

Examines structural and morphological changes to the body as the result of disease

Clinical Pathology

The study of disease using laboratory methods, examines blood and body fluids

Forensic Pathology

Examining the body to determine the time, manner, cause, and mechanism of death

Manner of Death

• Natural, Accidental, Homicide, Suicide

• about half of states also allow “undetermined” on the death certificate if there is not enough evidence to make a decision

Cause of Death

The trauma or injury that resulted in death.

• Primary = immediate cause of death

• Secondary = a contributing factor

ex: a man has a stroke and crashes his car

The crash is primary, the stroke is secondary

Mechanism of Death

Describes what organ or organ system failed as a result of the cause of death

ex: hemorrhage, cardiac arrest, sepsis

Medicolegal Autopsy

To determine exact cause and manner of death.

• to establish identity of the deceased

• to determine time since death

• to collect trace evidence

• aid in reconstruction

External Examination

• identify markings like tattoos, scars, birthmarks

• search for trace evidence, hairs, fibers

• extensive photographs

• wounds and traumas noted and photographed

Internal Examination

Standard Y-shaped incision made to the torso.

• body fluid and tissue samples taken and sent to toxicology

• all major organs removed, weighed, measured, checked for injury

• wounds traced from outside - in

• bullets/foreign objects removed

CO Poisoning

Cherry red in color

Defense Wounds

Wounds on palms from holding up hands when attacked

Organs

• polycystic kidneys

• tuberculosis

• stroke / infarction

Fat Embolism

• long bone trauma

• burns

• severe soft tissue trauma

Shaken Baby Syndrome

Torn axons

Traumatic Deaths

May be classified as:

• mechanical

• thermal

• chemical

• electrical

Blunt Force Trauma

Caused by dull or non-sharpened objects such as: baseball bats, bricks, lamps

Lacerations

Tears in the tissue, typically the skin

Normally produced by blunt objects

Incised Wounds

Wounds that have more depth than length or width

Caused by sharp objects

Exsanguination

Fatal loss of blood

When a major artery or the heart is damaged

Contusions

Also known as bruises

Due to crushing forces with extravasation of blood into the tissues

The skin surface is intact

Abrasions

Scrapes - due to tangential/shearing forces tearing the skin surface

They do not bleed, but ooze serum. Slight bleeding can occur with involvement of deeper layers

Lacerations

Soft tissue tears - from splitting of the skin

Full thickness wounds that bleed profusely

Underlying tissue bridging is present, edges may be ragged

Mechanical Trauma

Occurs when the force applied to a tissue, such as skin or bone, exceeds mechanical or tensile strength of the tissue

Can result from sharp or blunt force

Sharp Force Trauma

Refers to injuries caused by sharp implements, such as knives, axes, or ice picks

Penetration

• stops in the body

• bullet fragments should be recovered

Perforation

• through & through

• has an exit wound

Asphyxia

A type of mechanical trauma in which the body is deprived of oxygen

The brain is the most susceptible organ to asphyxia, unconsciousness follows loss of oxygen flow in 10 seconds

Can 1 of 3 ways:

• suffocation, covering the nose and mouth

• strangulation, compression of the structures

• chemical asphyxiation

Chemical Asphyxiation

Occurs when the oxygen in the air is replaced by some other gas, such as carbon monoxide

Chemical Trauma

Refers to damage and death which results from the interaction of chemicals with the human body

Thermal Trauma

Hypothermia or hyperthermia

Either condition can interfere with the normal physiological mechanisms that keep body temperature regulated

Electrical Trauma

Electricity can cause death

Rigor Mortis

The stiffness of death- Stiffening of muscles after death

Chemical changes leading to rigor begin immediately after death, involve the muscle fibers

Livor Mortis

Postmortem lividity / Postmortem hypostasis - Settling of blood after death

Postmortem discoloration of skin on dependent areas of dead body

Algor Mortis

The chill of death - Drop in body temperature due to heat loss from the body

Most reliable method for measuring PMI

Decomposition - Autolysis

The breaking down of one’s self

Digestive action of enzymes on proteins, carbohydrates and almost any other biomolecule

Putrefaction

Action of microorganisms in the body on tissues, reducing them to fluid

Produces a foul smelling putrefactive gas

Adipocere

Microorganisms break down fat into fatty acids “waxy fat”

Forms a wax material - not soap-like

• preservation mechanism

Mummification

Occurs when conditions of high environmental temps, low humidity, and good ventilation

Body dries quickly enough so microorganisms cannot act