Transcript Forensic Anthropology

Forensic Anthropology
What is Forensic Anthropology
 It
involves examining the human
remains (bones or decomposed
body) to identify the victim.
 It also involves determining the
cause and/or time of death.
Identification of Humans
A
dead body is subjected to
both
–Autolysis or internal digestion
–Putrefaction or bacterial action
 Condition
of a body found
depends on the time of death
and what elements it was
exposed to.
Identification Continued
 One
week out in the open
–Exposed to rain, heat, cold, or
other conditions of the area
 Two
weeks in water
–Submerged in the ocean, lake, or
other body of water
 Eight
weeks buried in the
ground
Identifying Artifacts
 Items
found near the body are
usually very helpful to investigators
 Examples
–Jewelry with names, initials, or
dates
–Clothing (style, ragged or
designer )
–Any other artifacts such as a
wallet or identification card
Artifacts Continued
 Corpse
Coverings/ Coffins are
good sources of evidence
– Wooden coffins contain tool markings
and indications of how and what
material was used to construct it
– Blankets and sheets may contain
biological information and tags from
manufacturer
– Plastic bags may have
fingerprints of the
perpetrator
Markings on the Corpse
 Distinguishing
marks on the
corpse help identify bodies
easily
 Examples
–Distinctive tattoos
–Birthmarks
–Surgical scars or other scars
 Many
times these markings
make positive IDs
Wounds or Disease as Evidence
 Scars
up to six months can be dated
by the amount of collagen that is
present
 Hip
replacements, pacemakers, heart
valves and other devices have serial
numbers that can be used to track
which hospital they came from.
Skeletons
 The
following can be determined
from intact bodies
–Age up to 5 years
can be determined
–Sex
–Race
–And height up to 1.5 inches
Skeletons
 Most
times you only have a few
bones
 The first question asked is “Are the
bones human?”
– Bumps
– Grooves
– Size and thickness
 Even
these indicators make it hard
to identify if the bones are human
Determining Sex
 Gender
specific changes in the
bones of a person do not occur
until puberty
 The male skeletons overall size
and thickness is “most of the
time” much larger than the
female.
 This however is not true for all
female and male skeletons.
Determining Sex
 Three
bones’ thickness and radius
are used in adults to determine sex
–Humerus- upper arm bone
–Radius- lower arm bone on the
thumb side
–Femur- upper leg bone
 Each of these are larger in males.
Determining Sex
 The
pelvic bones of the male and
female are the most distinctive and
useful.
 The woman’s pelvic bone is wider
for passage of children at child birth
 Men’s pelvic bones are only made
for movement so they do not have
a wide passage
Determining Sex
 The
sciatic notch is the place where
nerves pass on their way to the leg
 This notch is wider for women to
accommodate childbirth than in
men
 After childbirth a woman’s sciatic
notch may be scared or have
grooves because of the tearing of
ligaments

Use the male vs female pelvis to
visualize size difference.
Determining Sex
 The
jaw bone in male and
females gives anthropologists
clues to sex
 The male’s jaw bone is slightly
curved
 The females are normally
straight
Determining the Age From
Bones
 There
are six identifying parts and
properties of bones that are used to
identify the age of the victim from
the bones.
 Teeth
–Children age 12 and younger will
have 20 baby teeth
–Children 12-18 will have 28 teeth
–Wisdom teeth normally come in
around 18 to make 32 teeth
Six Identifying Markers of Age
 Skull
– As children develop from infants to
small children the pieces of their skull
fuses together.
– The amount of skull that has fused
together can be used to identify age
– This is not as useful as once believed
to be
Identifying Markers Continued
 Long
Bones of the Legs and
Arms
– The bone’s growth plate remains
open in the long bones of the legs
and arms until growth is complete.
– This feature helps scientists to age
people that are younger
than 25 years old
Identifying Markers Continued
 Pelvis
– There is a thin band of cartilage
uniting the left and right pubic bones
– This cartilage is called the symphysis
and its purpose is to absorb shock
when walking and to aid in child birth.
*See male vs female pevis picture
Identifying Markers Continued
 Ribs
– Sternal Areas- areas where the ribs
meet the breast plate.
– When you are young they are
rounded
– As you age they are jagged and
sharp
– Forensic Anthropologists can narrow
ages within 1.5 years up to age 30
then within 5 years to age 70.
Identifying Markers Continued
 Bone
Density
–Bone density is lost as you age
–Scientists can take X-Rays to
look at the density of bones to
determine age
–Osteoporosis and other diseases
must be taken into consideration
when determining age.
Determining Race
Determining race is very hard
 With racial mixing it can make it almost
impossible
 Three classifications for race

– Caucasoid
– Negroid
– Mongoloid
Determining Race
 Caucasians
(White)
–High rounded
or square skulls
–Straight faces
–Narrow,
protruding noses
Determining Race
 Negroid
(African-American)
–Lower and
narrower skulls
–Flatter noses
–Prominent,
protruding teeth
–Eye sockets are square
Determining Race
 Mongoloid
(Asian)
–Broad Round Skulls
–Eye Sockets are round
–Wide Facial Dimensions
Determining Time of Death

There are three different forms when
dealing with time of death
– Estimated: The best guess as determined
by the medical examiner
– Legal: The time the body was discovered
or pronounced dead.
– Physiological: The time the person’s body
vitals actually ceased.
Changes To The Body After
Death
 Temperature
Changes
 Muscle Stiffening
 Color Changes
Changes To The Body After
Death
 Temperature
Changes
– Normal body temperature is 98.6 F
– After death the body drops in body
temperature about 1.5 degrees/hr
– This changes depending on the
environment temperature
Changes To The Body After
Death
 Muscle
Stiffening
– Muscles stiffen after death because of
loss of ATP.
– Muscles stiffen more as putrefaction
begins
Changes To The Body After
Death
 Muscle
Stiffening
– After two hours the small muscles of
the face and neck become stiff
– This process continues downward
– After 8 to 12 hours the contracting
process finishes.
– After 18 hours the process reverses
Changes To The Body After
Death
 Muscle
Stiffening
– This is the least useful way to
determine time of death.
Changes To The Body After
Death
 Color
Changes
– Color changes occur because of the
stagnant blood in the blood vessels
– Places where the body is lying on a
hard surface or tight clothing is
against the body will be discolored.
– Pale places mean that the person’s
blood was highly oxygenated; purple
the blood was poorly oxygenated.
Identification Continued
Acids are sometimes believed to help
decompose or disfigure the body.
 Real facts about acids and corpses
– Quicklime (calcium oxide) when it
comes in contact with water
– CaO +H20
Ca(OH)2
(Slack Lime)
– This reaction and the heat kills
decomposing bacteria and
preserves the body

Identification Continued
 Burning
a body is another way that
criminals feel they can get rid of the
body.
 Real Facts about burning bodies
– The heat and time needed to
completely burn a body is around
1,500 F for two or more hours
– Structure fires typically burn about
500 to 2,000 F but don’t last long
enough