forensic anthropology what can it tell us?. vocabulary 1.anthropology – the scientific study of...
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Forensic Anthropology
What can it tell us?
Vocabulary1. Anthropology – the scientific study of the origins and
behavior as well as the physical, social, and cultural development of humans
2. Epiphysis – the presence of a visible line that marks the place where cartilage is being replaced by bone
3. Forensic anthropology – the study of physical anthropology as it applies to human skeletal remains in a legal setting
4. Joints – locations where bones meet5. Mitochondrial DNA – DNA found in the mitochondria
that is inherited only through the mother6. Ossification – the process that replaces soft cartilage
with hard bone by the deposition of minerals
Vocabulary7. Osteobiography – the physical record of a
person’s life as told by his or her bones8. Osteoblast – a type of cell capable of migrating
and depositing new bone9. Osteoclast – a bone cell involved in the
breaking down of bone and removal of wastes10. 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 age2. 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• 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)
More Rounded
More Square Mandible (Lower Jaw)
More V-shaped
Thicker and larger
Upper Brow Ridge (Zygomatic)
Thinner and smaller
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 – AnatomyBones 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
> 90 degrees
Triangular pubis
Shape of pubis
Rectangular pubis
Heart shaped Shape of pelvic cavity
Oval shaped
Longer, narrower,
curved inward
sacrum 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 Body
Bone Age
Arm Humerus bones in head fused 4-6
Humerus bones in head fused to shaft
18-20
Leg Femur: greater trochanter appears
4
Lesser trochanter appears 13-14
Femur: head fused to shaft 16-18
Femur: condoyles join shaft 20
Long Bones Chart 2
Region of Body
Bone Age
Shoulder Sternum and clavicle close 18-24
Pelvis Pubis, ischium completely united 7-8
Ilium, ischium, pubis fully ossified 20-25
All segments of sacrum united 25-30
Skull 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 cm2.10(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 RaceCaucasoid Negroid Mongoloid
Shape of Eye Orbits
Rounded, somewhat square
Rectangular Rounded, somewhat circular
Nasal Spine Prominent spine
Very small spine
Somewhat prominent spine
Nasal Index <.48 >.53 .48-.53
Prognathism Straight Prognathic Variable
Femur Fingers fit under curvature of femur
Fingers don’t fit under curvature of femur
Fingers fit under curvature of femur
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
• 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