Chapter 13 Forensic Anthropology:
What We Learn from Bones
By the end of this chapter you will be able to:
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Describe how bone is formed
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Distinguish between male and female skeletal
remains
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Explain how bones contain a record of injuries
and disease
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Forensic Science: Fundamentals & Investigations, Chapter 13
Chapter 13 Forensic Anthropology:
What We Learn from Bones
By the end of this chapter you will be able to:
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o
Describe how a person’s approximate age
could be determined
o
Explain the differences in facial structures
among races
o
Discuss the role of mitochondrial DNA in bone
identification
Forensic Science: Fundamentals & Investigations, Chapter 13
Forensic Anthropology
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Anthropology—the scientific study of all
aspects of human development and
interaction
Physical anthropology—studies human
differences
Forensic anthropology—studies these
identifying characteristics on the remains of
an individual
Forensic Science: Fundamentals & Investigations, Chapter 13
Historical Development
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1800s—scientists begin studying skulls,
differences in male/female anatomy, bone
formation
1897—Leutgert murder case: sausage
maker’s wife murdered; bone fragments found
in his factory
1932—the FBI opens the first crime lab
Smithsonian Institution partners with FBI
Forensic Science: Fundamentals & Investigations, Chapter 13
Historical Development
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1939—William Krogman publishes Guide to
the Identification of Human Skeletal Material
Soldiers killed in World War II are identified
using anthropologic techniques
DNA—new tool to analyze skeletons.
Focuses on mitochondrial DNA
Forensic Science: Fundamentals & Investigations, Chapter 13
Characteristics of Bone
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Bones are alive – capable of
growth and repair
Marrow—creates blood cells
Hormones affect the amount of
calcium in the blood and bones
Forensic Science: Fundamentals & Investigations, Chapter 13
Development of Bone
Osteoblast cells—where bones originate
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•
Ossification—process where osteoblast cells
migrate to the center of cartilage production and
deposit minerals
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Eventually become Osteocytes (mature bone cells)
Begins during the first few weeks of pregnancy
Periosteum – protective layer of nerves and blood
vessels. Keeps bones moist and aids in repair
Life cycle—bone is deposited, breaks down, and
replaced throughout our lives
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Forensic Science: Fundamentals & Investigations, Chapter 13
Development of Bone
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Osteoclasts—the 2nd type of bone cell
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Specialized to dissolve bone
Allows bones to reshape as they grow
Balances calcium levels in blood
Removes cellular wastes and debris from bones
Removes damaged part of bone
Osteoporosis—a deficiency of calcium in the
bones
Forensic Science: Fundamentals & Investigations, Chapter 13
How Bones Connect
cartilage—wraps the
ends of bones for
protection and
prevents scraping
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Forensic Science: Fundamentals & Investigations, Chapter 13
How Bones Connect
ligaments—bands that connect two or more
bones together
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Forensic Science: Fundamentals & Investigations, Chapter 13
How Bones Connect
tendons—connect
muscle to bone
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Forensic Science: Fundamentals & Investigations, Chapter 13
Aging of Bone
Under 30 years of age
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Over 30
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Bone tissue is built faster than it is broken down
bones increase in size
Bones deteriorate faster than they are built
Exercise slows deterioration, makes bones more
dense
Bones can become frail and brittle without enough
calcium
People hunch and shrink as their vertebrae collapse
Forensic Science: Fundamentals & Investigations, Chapter 13
What Bones Can Tell Us
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Osteobiography—bones contain a record
of the physical life
Analyzing bones reveals clues to gender,
age, height, and health
Examples:
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In a right-handed person, right arm bones might
be slightly larger than the bones of the left arm
X-rays may identify prior fractures, pins, artificial
joints
Forensic Science: Fundamentals & Investigations, Chapter 13
Gender
Female
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Smoother (Gracile)
Male
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Thicker, rougher (Robust)
Larger muscles require
stronger attachment of
tendons, makes bones
appear bumpy
Skull is more massive
Gender—Skull
Male
Characteristics
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Trait
Female
Characteristics
More square
Shape of eye
More rounded
More square
Mandible
shape from
underside
More V-shaped
Thick and larger
Upper brow
ridge
Thin and smaller
Forensic Science: Fundamentals & Investigations, Chapter 13
Gender—Skull
Male
Characteristics
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Trait
Female
Characteristics
Present
Occipital
protuberance
Absent
Low and sloping
Frontal bone
Higher and
more rounded
Rough and
bumpy
Surface of
skull
Smooth
Straight
Ramus of
mandible
Slanting
Rough and
bumpy
Nuchal crest
Smooth
Forensic Science: Fundamentals & Investigations, Chapter 13
Gender—Skull
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Which skull is smoother?
Which frontal bone is lower and sloping?
Which orbits are more circular?
Which jaw is more square, with an angle that is
closer to 90o?
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Forensic Science: Fundamentals & Investigations, Chapter 13
Gender—Pelvis
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An easy method to determine gender
The surface of a woman’s pelvis can be scared
The sub pubic angle of the female pelvis is
greater than 90o; the male’s, less
Forensic Science: Fundamentals & Investigations, Chapter 13
Gender-pelvis
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Female pelvic cavity is oval shaped, male pelvic
cavity is heart shaped
Female sacrum is tilted back, male is tilted
forward
Forensic Science: Fundamentals & Investigations, Chapter 13
Gender—Thigh bones
The male femur is
thicker and joins the
pelvis at a straighter
angle than the female
femur
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Forensic Science: Fundamentals & Investigations, Chapter 13
Determining Age of the bones
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Certain bones can reveal age
Absence or presence of cartilage
Not all bones mature at the same time
Must use a range of bones for a more
accurate assessment of age
Forensic Science: Fundamentals & Investigations, Chapter 13
Surface of Pubic symphysis
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Where the two pubic bones join
Surface of the bones at this joint change over
time
Forensic anthropologists compare casts of bones
from people of known ages
Forensic Science: Fundamentals & Investigations, Chapter 13
Age—Skull
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Infants have a soft spot (fontanel) that
slowly ossifies
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By about age 30, the Lamboidal suture at
the back of the skull closes (begins at 21,
accelerates at 26)
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By about age 32, the Sagittal suture
running across the top of the skull, back to
front, closes
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By about age 50, the Coronal suture
running side to side over the top of the
skull, near the front, closes
Not very reliable, must be used in
conjunction with other parts of the
skeleton
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Forensic Science: Fundamentals & Investigations, Chapter 13
Age
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At birth—450+ bones in the
skeleton
Adults— 206 bones
Epiphysis line—appears where
cartilage is replaced by bone
When the cartilage is fully replaced,
the line is no longer visible
This information can be used to
approximate a skeleton’s age
Forensic Science: Fundamentals & Investigations, Chapter 13
Age in children
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Eruption of teeth is most accurate
Presence of wrist bones
Forensic Science: Fundamentals & Investigations, Chapter 13
Age—Epiphysis
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Forensic Science: Fundamentals & Investigations, Chapter 13
Age—
Epiphysis
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Forensic Science: Fundamentals & Investigations, Chapter 13
Height
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An estimate of height can be made by
measuring one of the long bones
Gender and race is taken into consideration
Forensic Science: Fundamentals & Investigations, Chapter 13
How to Distinguish Race
Shape of the eye sockets
o Absence or presence of a nasal spine
o Measurements of the nasal index (width of nasal
opening : height of nasal opening)
o Prognathism (how far the upper jaw
Projects beyond the lower jaw
o Width of the face
o Angulation of the jaw and face
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Forensic Science: Fundamentals & Investigations, Chapter 13
Facial Reconstruction
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Facial muscles follow the contour of the skull
A face can be rebuilt from just skeletal remains
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Facial markers are positioned at critical locations
Clay is contoured to follow the height of the markers
Computer programs perform a similar function
Computer programs also can “age” missing
persons and criminals
Forensic Science: Fundamentals & Investigations, Chapter 13
DNA Evidence
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Bone contains little nuclear DNA but it does
contain mitochondrial DNA
Nuclear DNA degenerates before mitochondrial
DNA
Mitochondrial DNA is inherited only from the
mother
Compare results with living relatives on the
mother’s side of the family
Forensic Science: Fundamentals & Investigations, Chapter 13
Skeletal Trauma Analysis
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Forensic anthropologists determine if damage to
bones occurred before or after death
Differentiate between trauma and
environmental/animal damage
Distinct patterns exist for damage by
• Environment – chew marks from animals
• Sharp-force trauma – what kind of mark do you think a
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knife would leave?
• Blunt-force trauma – more cracks radiating from site of
impact, more damage to bones
• Gunshot wounds
Gun shot wound
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Forensic Science: Fundamentals & Investigations, Chapter 13
Sharp force trauma
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http://anthropology.si.edu/writteninbone/comi
c/activity/Evidence_of_trauma.htm
http://anthropology.si.edu/writteninbone/trau
ma.html
Forensic Science: Fundamentals & Investigations, Chapter 13