Download Forensic Anthropology

Forensic Anthropology
What can it tell us?
Vocabulary
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Anthropology – the scientific study of the origins and
behavior as well as the physical, social, and cultural
development of humans
Epiphysis – the presence of a visible line that marks the
place where cartilage is being replaced by bone
Forensic anthropology – the study of physical
anthropology as it applies to human skeletal remains in
a legal setting
Joints – locations where bones meet
Mitochondrial DNA – DNA found in the mitochondria
that is inherited only through the mother
Ossification – the process that replaces soft cartilage
with hard bone by the deposition of minerals
Vocabulary
7. Osteobiography – the physical record of a
person’s life as told by his or her bones
8. Osteoblast – a type of cell capable of migrating
and depositing new bone
9. Osteoclast – a bone cell involved in the
breaking down of bone and removal of wastes
10. Osteocyte – an osteoblast that becomes
trapped in the construction of bone; a living
bone cell
11. Osteoporosis – weakening of bone that may
happen due to lack of calcium in the diet
12. Skeletal trauma analysis – the investigation of
bones and the marks on them to uncover a
potential cause of death
What will we cover?
• How bone is formed
• Distinguish between male and female skeletal
remains based on skull, jaw, brow ridge, pelvis,
and femur
• Describe how bones contain a record of injuries
and disease
• Describe how a person’s approximate age could
be determined by examining his or her bones
• Explain the differences in facial structures among
different races
• Describe the role of mitochondrial DNA in bone
identification
History
• 1800s – scientists began using skull
measurements to differentiate
human bodies
• 1897 – Luetgert murder case; man
killed his wife and boiled down her
remains
– Fragments of skull, finger and arm found
• 1932 – FBI opened first crime lab
helping identify human remains
• 1939 – William Krogman published
Guide to the Identification of Human
Skeletal Material
History Cont’d
• WWII – remains of soldiers identified
using anthropological means
• Recently – new mitochondrial DNA
techniques have identified Romanov
family skeletal remains
Development of Bone
• Bones originate from osteoblasts
– Begin in fetus as soft cartilage
• Osteoblasts harden (ossificate) during first
few weeks of life to become bone
Development of Bone
• All of our lives – bone is deposited, broken
down and replaced
– Osteocytes – cells that form basic framework
for new bone
Development of Bone –
Functions of Osteoclasts
•
Osteoclasts –
1. Specialized to dissolve and shape bone as
you age
2. Also help maintain homeostasis of calcium
•
Dissolve bone when calcium is needed and
release into blood
– Can lead to osteoporosis
3. When bone is injured – secrete enzymes
that dissolve broken bone so new bone can
be laid down
Number of Bones
• Children – 450
– Children have bones
that eventually
suture together
• Adult – 206 after all
bones have fully
developed
How Bones Connect
• Joints – locations where
bones meet
• Three types of connective
tissue
– Cartilage – wraps ends of
bones for protection and to
keep from scraping
– Ligaments – bands of tissue
that connect two or more
bones
– Tendons – connect muscle to
bone
Aging of Bone
• What can bone tell us?
– Children build bones faster and bones grow in
size
– After 30 years – process starts to reverse and
bones deteriorate faster than built
• Can be slowed by exercise
– # of bones and their condition can tell a
person’s age, health, and calcium in food
Osteobiography
• The story of a life as told by bones
• Things we can see:
– Loss of bone density, poor teeth, signs of
arthritis
– Previous fractures, artificial joints, and pins
– Right-handed vs. left-handed
– Physical labor
Surface of Bones
• Males vs. Females
– Males – appearance
usually thicker,
rougher, bumpy
• Due to muscle
connections, bigger
body size
– Females – smoother
(gracile) and less
knobby (robust)
Skulls – Bones to Know
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Maxilla
Mandible
Zygomatic bone
Vomer bone
Frontal bone
Nasal bone
Orbit (eye socket)
Sphenoid bone
Sutures (between
skull bones)
Skulls – Male vs. Female
Frontal View
Male
Trait
Female
Low and sloping Frontal Bone
Higher and more
rounded
More Square
Shape of Eye
(orbits)
Mandible (Lower
Jaw)
More Rounded
Upper Brow Ridge
(Zygomatic)
Thinner and
smaller
More Square
Thicker and
larger
More V-shaped
Skulls – Male vs. Female Side
View
Male
Trait
Female
Present
Occipital
protuberance
Absent
Lower and more
sloping
Frontal bone
Higher and more
rounded
Bumpy and rough
Surface of skull
smooth
Angled at 90°
(straight)
Mandible (Jaw
bone)
Greater than 90°
(sloping)
Male Vs. Female Skull
Pelvis – Anatomy
Bones to Know
•Ilium
•Ischium
•Pubis
•Sacrum
•Coccyx
•Pubic symphysis
•Obturator
Foramen
Pelvis – Male vs. Female
• Things to
consider:
– Sub-pubic
angle
– Length, width,
shape, angle of
sacrum
– Width of ileum
– Angle of sciatic
notch
Pelvis – Male vs. Female
Male
Trait
Female
50-82 degrees
Subpubic
angle
Shape of
pubis
Shape of
pelvic cavity
sacrum
> 90 degrees
Triangular
pubis
Heart shaped
Longer,
narrower,
curved inward
Rectangular
pubis
Oval shaped
Shorter,
broader, curved
outward
Pelvis – Male vs. Female
• Other differences in female pelvis:
– Often weighs less
– Surface engraved with scars after female
has given birth
• Can be detected most at pubic symphysis
• Thigh Bone: Femur
– Angle of femur to pelvis is greater in females
and straighter in males
– Male femur is thicker than female femur
Distinguishing Age
• Bones don’t reach maturity at the same
time – To help tell their age:
– suture marks
– presence or absence of cartilage
Suture Marks
• Zigzag areas where
bones of the skull
meet
– In babies, some is
soft tissue that is
gradually ossified
– Suture marks slowly
fade to give
smoother
appearance as
bones age
Suture Marks Cont’d
• Coronal Suture:
– closed by age 50
• Lamboidal Suture:
– begins closing at 21
– accelerates at 26
– closed by 30
Cartilaginous Lines
• Epiphysis – line that
forms as cartilage is
replaced by bone
– Also called Epiphyseal
plate
• Line disappears as bone
completes growth
• Presence or absence of
this can approximate age
Long Bones
• When head of a
long bone has
fused with shaft
completely –
indication of age
• Each bone takes
different amount of
time
Long Bones Chart
Region of Bone
Body
Age
Arm
Humerus bones in head fused
4-6
Humerus bones in head fused
to shaft
18-20
Femur: greater trochanter
appears
4
Lesser trochanter appears
13-14
Femur: head fused to shaft
16-18
Femur: condoyles join shaft
20
Leg
Long Bones Chart 2
Region
of Body
Bone
Age
Shoulder Sternum and clavicle close
18-24
Pelvis
7-8
Pubis, ischium completely united
Ilium, ischium, pubis fully ossified 20-25
Skull
All segments of sacrum united
25-30
Lamboidal suture closed
21-30
Sagittal suture closed
32
Coronal suture closed
50
Estimating Height
• Measuring long bones like femur or
humerus can help estimate height
– Databases established that use mathematical
relationships
– Different tables for males, females, and races
– Example
• A femur measuring 49 cm belonging to an African
American male is found.
Calculation: 2.10(length of femur)+72.22 cm
2.10(49) + 72.22= 175.12 cm or
69 inches (5’9”)
Distinguishing Race
• This is losing its significance in differences
– Two biggest differences are in skull and
femur:
• Shape of eye sockets
• Absence or presence of nasal spine
• Nasal index – width of nasal opening X 100
height of nasal opening
• Prognathism – projection of upper jaw (maxilla)
beyond the lower jaw (mandible)
• Width of face
• Angulation of jaw and face
Distinguishing Race
Shape of
Eye Orbits
Nasal Spine
Nasal Index
Caucasoid
Negroid
Mongoloid
Rounded,
somewhat
square
Prominent
spine
Rectangular
<.48
>.53
Rounded,
somewhat
circular
Somewhat
prominent
spine
.48-.53
Prognathic
Fingers don’t
fit under
curvature of
femur
Variable
Fingers fit
under
curvature of
femur
Prognathism Straight
Femur
Fingers fit
under
curvature of
femur
Very small
spine
Other things bones can tell
• Left or right-handed
• Diet and nutritional dairy, esp. vit D and calcium
• Diseases or genetic disorders:
– Osteoporosis, arthritis, scoliosis, osteogenesis
imperfecta
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Type of work or sports based on bone structure
Previous injuries such as fractures
Surgical implants: artificial joints, pins
Childbirth
Facial Reconstruction
• Theoretically possible to build a face from
skeleton up using clay
– Related to size and shape of muscles and tissues that
overlay bones
• Specific markers on face are used
– Reconstruction attempted on
• Johann Sebastian Bach
• King Tut
– Same techniques used to age missing persons
– http://science.howstuffworks.com/body-farm.htm
Reconstruction of Bach
DNA Evidence
• Mitochondrial
DNA degrades
much, much,
much slower
– Can be extracted
from bones and
compared to
living relatives on
mother’s side of
family
Skeletal Trauma Analysis
• Forensic scientists trained to recognize
marks made by weathering and animals
– A knife wound on rib leaves a mark that might
look similar to rodent chew marks
• Goal is to tell the difference in marks made
by patterns in weapons, and marks made
by weathering
– Forensic anthropologists try to determine
cause of death and weapon
Skeletal Trauma Analysis
• Sharp-force and blunt-force trauma,
gunshot, and knife wounds all have
distinctive patterns
• Living bone flexible compared to old and
brittle bone
– Bones break differently when living versus
when old