honors forensic science. i. forensic pathology a. pathology = branch of medicine associated with...

FORENSIC PATHOLOGYHonors Forensic Science

I. Forensic Pathology

A. Pathology = branch of medicine associated with the study of structural changes caused by disease or injury

B. Pathologist = medical doctor who specializes in determining how disease affects the body

C. Forensic just adds the legal aspect to field

II. Coroner vs. Medical Examiner

A. Coroner i. Usually elected official Ii. Does not have to be a doctor

b. Medical Examiner

i. Often have both law enforcement and quasi-judicial powers

Ii. Operate out of centralized offices Iii. Usually attends crime scenes

Iv. Duties 1. find evidence 2. preserve evidence 3. report accurately 4. also decides who gets autopsied

A. Traumatic B. Unusual C. Sudden D. unexpected

II. Autopsy

A. Purpose – observe and make a permanent legal record as soon as possible of the gross and minute anatomical peculiarities of recently deceased body

b. Goals

i. Determine identity of decedent Ii. Determine cause of death – direct

agent that leads to death (ex. Bullet, poison)

Iii. Determine manner of death 1. Accident 2. Suicide 3. Murder 4. natural

Iv. Determine mechanism/mode of death – what happened to body as a result of its run-in with the cause (ex. Bullet tears hole in aorta and blood fills chest cavity)

V. Determine time of death

C. ME/Pathologist protocol in approaching body for autopsy

i. Visual inspection Ii. Injury inspection Iii. Internal exam Iv. Presentation to other experts V. Reconciliation of exhibits Vi. Presentation of findings (autopsy

reports)

d. Visual Inspection

i. Prior to this blood sample taken, x-rays, weight and measurements are done

Ii. Begins with clothed or nude body depending on circumstances at time of death

Iii. Body is photographed with attention to unusual details

Iv. Trace evidence is collected

V. Clothing is removed and each piece is air-dried and packaged separately for processing with descriptions

Vi. Head hair combed

Vii. Rape kit may be done

Viii. Body openings examined

Ix. Hands (should have been bagged at scene) examined – ex. Damaged nails, nail scrapings, GSR

X. Fingerprint/footprint cards

Xi. Entomological samples collected

Xii. Notes of injuries and photos

Xiii. Overall conditions of body noted

Xiv. May use special lights to see bruises etc.

Xv. Body mark documentation – tattoos, scars

e. Injury Inspection – commonly seen injuries and causes of death i. Asphyxia

1. insufficient amounts of oxygen reach the brain or other organs

2. Natural causes

A. Disease that cause the respiratory system to shut down i. Ex. Emphysema Ii. Pneumonia Iii. Flu Iv. Asthma V. Larynx disorders

3. Criminal means of asphyxia A. Strangulation

i. Homicide – manually or by ligature – marks on neck are more horizontal than in suicide

Ii. Suicide – generally see marks on neck that curve upwards

Iii. Accidental - rare

Iv. Characterized by 1. intensive heart congestion – enlarged

heart

2. venous engorgement

3. cyanosis – blue discoloration of lips and fingertips

b. drowning

i. Results from inhalation of water which causes choking and rapid formation of mucus in throat and windpipe

Ii. Mucus inhibits respiration

Iii. Characterized by

1. foam cone covering mouth and nose

2. fluids in lungs

iv. 5 stages of drowning

1. surprise – person is stunned and inhales water

2. holding breath – person tries to hold breath while struggling

3. pink foam – person inhales deeply and pink foam is expelled

4. respiratory arrest – thoracic movement and pupils dilate

5. final struggle – 3-4 quick attempts to breathe and find air

c. Smothering

i. Occurs when airways are closed by obstructing object

Ii. If soft object – usually no visible sign of trauma expect for small lacerations on lips

Iii. Cyanosis may or may not be present

Iv. Petechial hemorrhage – pin-point blotches or red spots on face, typically around eyes

ii. Wounds –can often reconstruct what happened from types of wounds 1. Penetrating

A. Bullet wounds i. follow principles of physics Ii. Velocity is most important factor, not

size of bullet Iii. fragmenting ammunition designed to

spread out and hit vital organs

Iv. High powered rifles more deadly than handguns or shotguns

V. Entry and exit wounds are important

Vi. Entry wound generally smaller than exit

Vii. Often able to identify caliber of weapon from entry wound

Viii. Often see powder burns 1. held at distance – no other surface

information than wound 2. held on skin – “rim burns” 3. held a few inches away – soot on

wound but no burn – hair may be scorched

4. held a few inches to a few feet away – “stippling”

b. Stab Wounds

i. Slash wounds 1. look like bullet wounds that graze the

skin 2. hesitation marks – often seen in

suicide cases 3. typically rectangular in shape

Ii. Incision wounds

1. lengths greater than depth 2. greater amount of sub-surface tissue

exposed in almost oval fashion

Iii. Puncture Wounds

1. almost no geometric shape, except perhaps circular

2. most distinguishable from clean –cut edges

Iv. Pre-mortem wounds gape and bleed profusely

V. Post – mortem wounds do not bleed profusely

Vi. If attacker stuck victim and twisted object, more damage is caused and death more likely

2. Non-penetrating

A. Results from clubbing, kicking, or hitting victims

B. Has a crushing effect on body resulting in contusions, abrasions, lacerations, fractures, or rupture of vital organs

C. Red-blue contusions (bruises) almost always present

D. Brain contusions

i. Difficult to analyze Ii. Trauma most severe on opposite side

of impact

E. Wounds to body area take longer to cause death

i. Due to process of subdural hematoma (blood clot) that travels to brain

iii. Miscellaneous

1. Rape Wounds A. Examination of genital area for signs

of tearing, scratching, or bruising B. Existence of venereal disease and/or

pregnancy C. Foreign pubic hair, blood stains,

seminal stains collected D. Sometimes able to collect DNA

2. Poisioning/Drugs

A. Usually determinable by looking at discolorations of body i. Cherry-red lividity is sign of carbon

monoxide Ii. Other toxins give off unusual odors Iii,. Needlemarks between fingers and/or

toes suggest drug use Iv. Diagnosis requires toxicological

confirmation

3. Burn Wounds

A. Caused by heat, a chemical or electricity

B. Often found in “pugilistic” position with clenched fist

C. Heat generally causes the protein in body to contract

D. Electrical burns – occur in pairs; one from point of contact, other from grounding point where current passes out of body

4. Traffic Fatalities

A. Analyzed to determine if victim was driver, passenger or pedestrian

B. Motorcycle injuries more severe C. Automobile drivers often have

circular impression in chest area D. Passengers normally have

extensive knee and spinal injuries

E. Pedestrian injuries i. Extensive lower body injuries –

“bumper fractures” Ii. The lower on the leg the “bumper

fracture”, the more likely it is the driver attempted to slow down

Iii. Run-over injuries are distinguishable by amount of compression tissue damage

f. Internal Exam

i. “Y” incision Ii. Organs removed and examined

for injury and disease and then weighed

Iii. Stomach contents examined – may help determine time of death and tie victim to certain places

Iv. Blood for toxicological screens

V. Bladder – fluid removed for drug analysis

Vi. Reproductive organs tested for pregnancy

Vii. Generally, organs are replaced unless something is amiss

Viii. Head 1. eyes/eyelids – sample vitreous fluids 2. hemorrhages may indicate hanging

or strangulation 3. cut off face to examine skull 4. skull opened and brain examined

IV. Special case autopsy

A. Fetal Death i. A fetus of less than 500 g is

“miscarried” – expelled from mother’s body through natural or traumatic means 1. no autopsy is done and no death

certificate is issued

Ii. A fetus of more than 500 g is born dead – a still birth

1. in absence of violence or suspicion, a special fetal death certificate is issued with cause of death “non-viability” of fetus

Iii. A fetus of more than 500 g is born alive and then dies

1. standard death certificate 2. autopsy usually done

b. exhumations

i. Order to exhume body must be obtained from the court

2. problems – embalmed bodies have had blood drained and replaced with formaldehyde compounds; remains may have skeletonized

c. Partial bodies/amputations

i. Difficult to establish cause of death if entire body is not present

V. Autopsy Reports

A. Pathological diagnosis B. Cause of death C. Contributing cause of death –

usually a pre-existing illness or condition

1. ex. Pneumonia or asthma

D. Mechanism of death i. Usually anything expressible only in

medical jargon Ii. Ex. Lung sacs became obstructed

and could no longer transport oxygen

E. Immediate cause of death

i. Usually gets at cause of death Ii. Expressed in medical jargon or in

laymans terms Iii. Ex. Asphyxia or wound

F. Manner of death –

Usually is mechanism plus immediate cause; suicide, homicide, accidental, natural or unknown