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Unit E
Forensic Medicine
What is Forensic medicine?
• Latin word –forensics
• Means public discussion or debate
• Science used in justice system for legal
purposes
• Facts based on scientific investigation
• Goal is to determine facts and truth
• Uses multiple science specialties
Forensic Scientists
• Television enhances the image
of forensic science….not
always accurate
• Forensic scientists are
involved in all aspects of
criminal cases.
• The forensic scientist's goal is to use
all available scientific information to
determine the facts and, subsequently,
the truth.
• The forensic scientist might determine:
– The validity of a signature on a will,
– If a corporation is complying with
environmental laws,
– The origin of physical evidence at a
crime scene
Document Examination
• This discipline involves all special
relationships that may exist between
document and inscription and how it
relates to a person or sequence of
events.
• This includes forgery, counterfeiting,
and handwriting analysis.
Firearms and Toolmarks
• Typically, this includes matching
bullets to the gun that fired them.
• Toolmark identification involves the
identifying characteristics between
tools, such as a pry bar, and the object
on which it is used, such as a door
frame.
• Also included in the category are
explosives and imprint evidence.
Techniques and examples
• Autopsy- earliest technique
• DNA typing - most recent
Techniques and Examples
• Forensic anthropology
• Odontology: the proper examination,
handling and presentation of dental
evidence in a court of law
• Blood testing
Autopsies
Definition and Purpose
•
•
Postmortem examination
Used to determine the cause of death and
how the person died.
Autopsies
Legal Requirements
1. Coroner- a public official who investigates
sudden, suspicious, or violent death to
determine the cause - Coroner’s office is
responsible for conducting autopsies
2.Medical examiner - a physician who is
appointed by a state or local government to
establish the cause of somebody's death,
especially in cases where death is not the
result of natural causes.
Pathology -the scientific study of the nature,
origin, progress, and cause of
disease…examines tissues, fluids, etc.
Reason for autopsy
1. Determine what disease or injury
caused death
2. Medical Diagnosis- confirmation and
understanding
3. Evaluate possible public health issue
Preparation
1. If not required by law, permission
needed from next of kin
2. legal consent form
Procedure
1. First – Examine complete medical
history and review of records
2. External physical exam
a. body tag
b. weight and height
c. examine clothing and valuables
d. document scars, tattoos, injuries,
wounds, bruises
e. foreign objects noted (i.e. piercings,
knives, protruding shovel, etc.)
3. Photos and x-rays taken, if needed
4. Complete internal exam
a. dissection of head and abdomen
b. organs removed, weighed,
measured, and examined
c. tissue samples examined under
microscope
d. fluid samples tested for drugs,
infection
5. After autopsy complete, legal death
certificate completed
Results
1. Natural deathdisease or old age
2. Unnatural deathunexpected, or
unusual cause
Methods of determine time of
death
1. Traditional indicators
a. rigor mortis (stiffening of
the muscles of the body
after death)
- begins three hours after
death in face and eyelid
muscles
- takes twelve hours to
affect entire body
- process reverses after 36
hours
2. Lividity (hypostasis)
a. visible after 30-60 mins
b. red cells settle and skin below turns red
c. in 6-10 hours, color becomes permanent
3. Body temperature
a. falls at rate of approximately one
degree per hour
b. obesity and warm environment slows
cooling
Using body temp to determine time of
death is not totally reliable and can be
manipulated
DNA typing and Forensic Anthropology
DNA typing
1. What is DNA?
a. nucleus of cells contain RNA/DNA
b. DNA – deoxyribonucleic acid
c. nucleus has 23 pairs of
chromosomes made up of DNA
d. within each pair, one chromosome
from sperm and one from egg
2. What makes DNA individual?
a. Four chemicals- adenine, guanine,
cytosine, and thymine
b. Chemicals strung together = DNA
code
c. Some sections of DNA vary from
individual to individual
d. Scientists can link a strand of DNA to
a given individual
3. Criminal investigations
a. specimens: blood,
hair, bloodstained
clothing
b. provides powerfully
compelling evidence
Forensic anthropology
1. Skeletal Anatomy
a. 206 bones
b. Man = 12 pounds,
woman = 10 pounds
2. What bones show
a. How person lived
b. Debilitating illnesses
(rickets, polio, healed
fractures, osteoporosis)
c. Right or left handed
d. Clues to occupation
3. Questions answered with full skeletal
remains
a. age of person at time of death
b. sex of person (skull and pelvis)
c. race (skull)
d. height
Odontology and Serology Studies
in Forensic Medicine
Odontology
1. Characteristics of teeth after death
a. no other part of body lasts longer
b. in fires, teeth usually only means to
ID remains (i.e. after 9/11/01)
c. no two people have identical teeth
2. Requirements for identification
a. needs dental records
b. dentists chart five surfaces of each
tooth in a grid (odontogram)
c. can also provide “bite mark”
evidence
3. Teeth useful in determining subject’s
age
Serology
1. Blood type
a. Four types (A, B, O,
and AB)
b. Rh factor – protein…if
you have it you are Rh +
if you don’t you are Rh c. female blood cells
have Barr Body…so you
can tell if a blood
sample is from a male or
female
2. Criminology
a. Kastle-Meyer test to determine if it is
indeed blood
b. Precipitin test – determines animal or
human blood
c. You can determine blood type and
gender from blood specimen
d. Provides reliable and informative
evidence