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Forensic Anthropology

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Forensic Anthropology Pearl was a female who died in her early forties approximately three hundred years ago. She was Caucasian, of European ancestry and stood about ... – PowerPoint PPT presentation

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Title: Forensic Anthropology


1
Forensic Anthropology
2
What Questions Can Forensic Anthropology Answer?
  • Race
  • Sex
  • Approximate age
  • Approximate stature
  • Pathologies (diseases)
  • Traumas (injuries)
  • Other individual traits

3
Identity of Decomposed or Skeletal Remains
  • Are the remains human or animal? (butchers
    remains and skeletal remains of dead pets etc.
    may be found in unlikely places)
  • Are they really bones? (wood, stones)
  • How many bodies?
  • How long dead? - recent or ancient (e.g.
    construction or digging at an old burial site)
  • Cause of death?

4
How does this Work?
  • Regression equations used to determine sex, age,
    stature, and race of skeletal remains.
  • Regression equations are mathematical equations
    developed from studies of bones of individuals of
    known sex, age, race, and stature, and are used
    to predict such things of even fragmentary
    skeletal remains."

5
Sex Estimation
  • The sex of an individual is determined, when soft
    tissue is not present, by a number of skeletal
    indicators.
  • The more indicators used to determine sex, the
    more accurate the results.
  • A forensic anthropologist is analytically limited
    by the bones present and the condition of the
    bones.

6
  • Bones of men are larger and more robust than
    bones of women.
  • Some bones display specific features which can be
    used to help determination of the sex of the
    skeleton. The best indicators are the
  • Skull
  • Pelvis
  • Head of the Femur

7
Sex Estimation long bones
  • Usually related to size in adult long bones
  • Male bones usually larger, longer in a single
    population be cautious if different populations
    are involved
  • Maximum diameter of head of humerus and head of
    femur may be used (Bass).
  • Much more difficult to estimate sex in childrens
    skeletons.

8
Head of the Femur
  • In men, the diameter of the head of the femur is
    larger than 51 mm.
  • In women, the diameter of the head of the femur
    is less than 45 mm.

9
Other femur features
10
Sex Estimation Skull
  • Good area for sex determination
  • Generalization male skull more robust,
    muscle-marked than female, but ABSOLUTE
    DIFFERENCES SELDOM EXIST
  • Sex estimation face, mandible, vault

11
Sex Estimation Face
  • 1. Supraorbital (Brow) ridges more prominent in
    males
  • 2. Superior orbital margin sharper in females
  • 3. Palate larger in males
  • 4. Teeth larger in males
  • 5. Mastoid process more prominent and rugged in
    males.
  • 6. Orbit (Eye socket) Rounder in females, more
    rectangular in males
  • 7. Chin more pronounced in males and larger jaws.

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16
Pelvis
  • The pelvis of a woman is wide and circular
    whereas the pelvis of a man is narrow and
    heart-shaped.
  • Two angles, the sub-pubic angle and the sciatic
    notch, cause the differences in the shape of the
    pelvis.
  • In women, the sub-pubic angle and sciatic notch
    are wide. In men, the sub-pubic angle and sciatic
    notch are narrow.

17
Pubis Bone Traits Related to Sex
Trait Female Male
Ventral arc a roughened projection of bone visible on the anterior surface of the pubis bone Present Absent
Pubis body width (mm) 40 25-30
Subpubic angle (degrees) angle made by the inferior borders of the articulated pubis bone gt90 lt90
18
Male Pelvis Subpubic Notch
19
Female Pelvis Subpubic Notch
20
Sciatic notch comparison which is female?
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Determining Ages of Skeletons
  • Bone growth stops at about 20 yrs. of age in
    humans.
  • Adult bone continuously adapts to prevailing
    stresses by appropriate deposition and
    resorption.
  • Deposition and resorption are under hormonal
    control - integrated with regulation of blood
    calcium levels.

24
Skeletal Age
  • Skeletal age is the estimated age at which a
    person died. Skeletal age can be determined by
    looking at the following
  • sutures of the skull
  • teeth
  • ribs
  • vertebrae
  • growth areas of the long bones epiphyses

25
Sutures of the Skull
  • When a baby is born, the skull is still growing.
    To accommodate this growth, the different bones
    of the skull are separate.
  • By the age of 7, all the different bones have
    finished growing and the fontanelles have
    disappeared.
  • Most sutures begin fusing no earlier than 18
    years of age

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Skull Sutures
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Fused sutures in adult
30
The Teeth
  • The teeth are arranged in upper and lower arches.
    Those of the upper are called maxillary those of
    the lower are mandibular.

31
  • There are four types of teeth with very different
    shapes
  • Incisors (2)
  • Canines (1)
  • Premolars (bicuspids) (2)
  • Molars (2-3)
  • Individual teeth are quite distinct, even when
    lost from a jaw.

32
Dental Formula (from the midline)
  • Primary (deciduous) teeth.
  • incisors, two upper and two lower
  • canines, one upper and one lower
  • molars two upper and two lower equals ten per
    side.
  • Permanent teeth.
  • incisors, two upper and two lower
  • canines, one upper and one lower
  • premolars, two upper and two lower
  • molars, three upper and three lower.

33
Teeth
  • The first teeth to appear are the incisors, which
    are followed by canines and molars.
  • When chewing food, teeth grind down.
  • Comparing different teeth gives an idea of how
    long the teeth have been used.
  • Eventually teeth may be lost, due to caries or
    attrition.

34
X-Rays Are Used to Date Skulls
  • This is the side view of the dentition of a six
    year old boy.
  • There is still some variation from person to
    person in the order in which the teeth erupt.

35
Baby Teeth Permanent Teeth Incisors
7-12 months Incisors 6.5 years
Canines 2 years Canines 10.8 years
Premolar 1 none Premolar 1 10.4
years Premolar 2 none Premolar 2 11
years Molar 1 3 years Molar 1 6.2
years Molar 2 3 years Molar 2 12.2
years Molar 3 none Molar 3 18
years
36
Teeth with 6 year molars
Baby Teeth
Teeth with 12 year Molars
Teeth with Wisdom Teeth
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Dental Disease - Cavities, Abscesses, and
Attrition
39
Ribs
  • Because of breathing, the front part of the ribs
    is constantly moving.
  • As a person gets older, the front part of the
    ribs begin to change and form bony spikes.

40
Vertebrae
  • As a person gets older, bony spikes can also
    start growing on the vertebrae.
  • This starts at approximately 40 years of age.

41
Growth areas of the long bones (epiphysis)
  • From birth to 25 years of age, a person grows at
    a relatively constant rate.
  • Growth takes place at the ends of the long bones.
  • At a certain age, growth is completed and this
    can also be seen on the bone.

42
Epiphyseal Fusion
  • The pattern of fusion of bone ends (epiphysis) to
    bone shaft (metaphysis) in each bone indicates
    age.
  • The upper arm stops growing at the shoulder at
    approximately age 20 and at the elbow at
    approximately age 14.5.
  • The upper leg stops growing at the hip at
    approximately age 17.5 and at the knee at
    approximately age 18.

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Determining Ages of Skeletons
  • Cranial suture fusion is less reliable.
  • Pubic symphysis changes slightly with age.
  • Arthritic changes and osteoporosis give further
    clues.

45
Height
  • An intact corpse can be measured, but a
    disarticulated or incomplete skeleton has to be
    pieced together.
  • Stature
  • 3.26 x (humerus) 62.10 stature /-4.43cm
  • 3.42 x (radius) 81.56 stature /-4.30cm
  • 3.26 x (ulna) 78.29 stature /-4.42cm
  • (there will be 2 calculations for stature, based
    on the upper and lower margin of error)

46
Race or Ethnic Group Determination
  • The skull is the only reliable bone.
  • Caucasoid (all whites)
  • Negroid (all blacks - African, African Americans
    and West Indians)
  • Mongoloid (Chinese, Japanese, American Indians)

47
In Caucasoids Nasal openings are narrow. Face
is flatter
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In Mongoloids Shovel-shaped" concave upper
incisor teeth. Cheekbones (Zygomatic arches)
are wider and more prominent. Greater width
between eyes.
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In Negroids Face projects forward Nasal
opening is wider
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Comparison of the extent of ramus inversion in
the mandible of an individual with caucasoid
ancestry (top) and one with negroid ancestry
(bottom)
58
Minimum Number of Individuals
  • Used in mass graves- like in Yugoslavia or
    Afghanistan and mass disasters.
  • Count all the bones and assign left vs. right.
  • Use the highest number of a bone as the minimum
    number.
  • Also, can assign bones to individual skeletons
    and then count them.

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Dating of Human Skeletal Remains
  • Are they ancient or modern bones? (i.e. greater
    or less than 50 years).
  • Rate of skeletonization is highly variable. In
    the tropics a body can be reduced to a skeleton
    in 3 weeks.
  • Remarkable preservation of body is seen in acidic
    peaty soil
  • Thus, environmental conditions have to be taken
    into account.

61
2400 year old bog body from Denmark
62
Age of Human Remains
  • Naked eye appearance is unreliable
  • Tags of soft tissue, periosteum, ligaments etc,
    indicate less than 5 years old.
  • Soapy texture of surface indicates age less than
    a few decades.
  • Light, crumbling bones are likely to be a century
    or more old.

63
Laboratory Tests Can Help
  • Immunological reaction between bone extract and
    anti human serum ceases within months of death.
  • If blood pigments are present bones are usually
    less than 10 years old.
  • Up to 20 amino acids may be identified in bones
    less than a century old.
  • Fluorescence of freshly sawn bone surface under
    UV light diminishes after 100 years.
  • New bones contain 4.0 - 4.5 gms nitrogen 2.5
    gms indicates approximately 350 years.
  • Radioactive carbon dating indicates which century.

64
Taphonomy
  • Coined from the Greek words taphos, for "burial,"
    and nomos, for "law."
  • Forensic Taphonomy The Postmortem Fate of Human
    Remains
  • Skeletal trauma, decomposition, and dispersal of
    remains.
  • Weathering, a taphonomic process, is very useful
    in determining the elapsed time since death.

65
Facial Reconstruction
  • Skull can be scanned into a computer and
    "fleshed" by computer reconstruction to give
    likely facial appearance in life.
  • Unfortunately eye color, hair color and lips are
    independent of bony structure.

66
  • Pearl was a female who died in her early forties
    approximately three hundred years ago.
  • She was Caucasian, of European ancestry and stood
    about 5'1".
  • Her dental health was extremely poor and she had
    lost 63 per cent of her teeth prior to death. She
    had no teeth on either side of her jaw. This was
    most important as the loss of those teeth would
    evidence themselves in the final reconstruction
    as sunken cheeks. Of her remaining teeth, the
    condition was poor and she had several abscesses.
  • During her lifetime, there are indicators that
    she also suffered from acute infections, rickets,
    sinusities, an upper respiratory infection,
    arthritis, and gout. Whew--all this in an era
    when aspirin didn't exist!
  • On the other hand, it was determined that she was
    very muscular, as the ridges on her long bones
    were very developed.

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The artist utilizes proper tissue depth data
determined by race, gender, and age. Artificial
eyes are placed in the skulls eye sockets,
centered and at the proper depth. The tissue
markers are glued directly onto the skull. Clay
will be systematically applied directly on the
skull, following the skull's contours paying
strict attention to the applied tissue markers.
69
Various measurements are made, and logged, to
determine nose thickness/length, mouth
thickness/width, and eye placement. Information
such as geographic location of where the deceased
lived, his or her lifestyle, and the various
information provided to the artist by the
Forensic Anthropologist and other professionals,
is heavily relied upon when completing the
reconstruction.
70
This woman had missing side teeth and a small
jaw. Hair is added by applying clay or a wig.
Various items (glasses, clothing, hats) may be
applied to better accentuate the features of the
individual. This method can be very successful.
71
Cause of Death
  • Anthropologists can distinguish between marks
    from the result of a weapon attack and those
    resulting from the gnawing and biting of bones by
    scavenging animals.
  • They can also determine the exact kind of weapon
    and animal, and they can tell if a wound is old
    or if it occurred at death.
  • They can be called upon to testify as to the type
    of weapon used (saw vs. knife).

72
Lizzie Bordons Fathers skull Ax Whacked.
73
  • Two outstanding cases of the use of forensic
    anthropology to successfully solve unsolved
    mysteries are the cases of Francisco Pizarro.

74
Pizarro conquered the Incas.
  • Pizarro was hated by the Peruvians because he was
    a brutal ruler. On June 26, 1541 (at age 66), he
    was stabbed to death by a crowd of angry subjects
    and in view of many witnesses (Dickerson 1993).
  • His brutal death is not questioned due to the
    well documentation at the time. It was his
    remains that were questioned.

75
  • In the 1890's, Peruvian officials decided to put
    Pizarro's remains on exhibit. "They asked
    officials at the Cathedral of the Plaza de Aramis
    in Lima for Pizarro's body and were directed to a
    mummy, which they put on view." (Dickerson 1993)
  • In 1978 workers discovered a secret niche that
    had been walled over in the cathedral, and on a
    shelf in the niche was a box with a skull and an
    inscription that identified it as the head of
    Pizarro.
  • Another box was found containing the bones of
    several unidentified individuals (Dickerson
    1993).

76
The Question was, "Who was the real Pizarro?"
  • An investigation of the bones in the second box
    led to the discovery that the postcranial bones
    matched the skull in the first box.
  • These bones and the skull were then placed
    together and prepared for study to determine if
    they had marks consistent with sword or knife
    wounds.

77
Whos the Mummy?
  • Just by using visual observation, researchers
    could tell that the skeleton had been stabbed
    many times, dying in the same way as Pizarro was
    reported to have died.
  • The location of the wounds showed that the victim
    had been stabbed "about the head and body and
    apparently had tried to shield himself with his
    arm, a reaction common in stabbing deaths."
    (Dickerson 1993)
  • On the other hand, the mummy had no such injuries
    at all (Dickerson 1993).
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