Forensic Anthropology: Studying Bonessciencewithschisel.weebly.com/uploads/2/3/4/2/... ·...
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Forensic Anthropology:
Studying Bones
http://people.stu.ca/~mclaugh/skeleton8a.GIF
Reading
• Read the chapter with a partner, finish the handout and answer these questions:
– What is the function of osteoblasts?
– What is the function of osteoclasts?
– What is the function of osteocytes?
– Using these terms, describe ossification
– How is it that the number of bones can be different?
– Where does mitochondrial DNA originate (inherited), why does it have to be used for bones?
1. Determination of Sex• Pelvis is the best bones (differences due to
adaptations to childbirth)
females have wider sub-pubic angle
females have a sciatic notch > 90
females have a broad pelvic inlet
1. 1.
1.
2. 2.
2.
3.3.
3.
Determining Sex using the skull
Forensic Anthropology
Figure 2 Male (left) and female (right) skulls
Male (left) and female (right) skulls
1. Determination of
Sex: Cranium
• Crests and ridges more pronounced in males (A, B, C)
• Chin significantly more square in males (E)
• Mastoid process wide and robust in males
• Forehead slopes more in males (F)
Determining Culture - race
Three major anthropological racial groups based
on observable skeletal features:
Caucasoid: European, Middle Eastern and East
Indian descent
Negroid: African, Aborigine and Melanesian
descent
Mongoloids: Asian, Native American and
Polynesian descent
Forensic Anthropology
White, Asian, African
From: Beyers, S.N. (2005). Introduction to Forensic Anthropology
Determination
of Race:
Caucasian
http://upload.wikimedia.org/wikipedia/en/c/cc/Skullcauc.gif
Trait
Nasal Index: <.48
Nasal Spine: Prominent spine
Nasal Silling /
Guttering:
Sharp ridge
(silling)
Prognathism: Straight
Shape of
Orbital
Openings:
Rounded,
somewhat
square
Nasal spine:
Prominent
Progathism: straight
Orbital openings:
round
Determination of Race:
Asian (Asian decent
and Native American
decent)
http://upload.wikimedia.org/wikipedia/en/b/b3/Skullmong.gif
Trait
Nasal Index .48-.53
Nasal Spine
Somewhat
prominent
spine
Nasal Silling/
GutteringRounded ridge
Prognathism Variable
Shape of
Orbital
Openings
Rounded,
somewhat
circular
Determination of Race:
African: (everyone of
African decent and
West Indian decent)
http://upload.wikimedia.org/wikipedia/en/5/5e/Skullneg.gif
Trait
Nasal Index >.53
Nasal Spine Very small spine
Nasal Silling/
GutteringNo ridge (guttering)
Prognathism Prognathic
Shape of Orbital
OpeningsRectangular or square
Nasal Silling and Guttering
From: Beyers, S.N. (2005). Introduction to Forensic Anthropology
General Shapes of the Eye Orbits
From: Beyers, S.N. (2005). Introduction to Forensic Anthropology
Warm up
• What do you think is the best way to
determine age from bones?
• What changes do your bones go through
as you age?
• What age does the skeleton “stop”
changing?
2. Determination of Age from
Bones• Ages 0-5: teeth are best – forensic odontology
– Baby teeth are lost and adult teeth erupt in predictable patterns
• Ages 6-25: epiphyseal fusion – fusion of bone ends to bone shaft– epiphyseal fusion varies with sex and is typically
complete by age 25
• Ages 25-40: very hard
• Ages 40+: basically wear and tear on bones– periodontal disease, arthritis, breakdown of pelvis,
etc.
• Can also use ossification of bones such as those found in the cranium
Determination of Age
• The long bones are those that grow primarily by elongation at an epiphysis at one end of the growing bone. The long bones include the femurs, tibias, and fibulas of the legs, the humeri, radii, and ulnas of the arms, and the phalanges of the fingers and toes.
• As a child grows the epiphyses become calcified (turn to hard bone)
Epiphyseal Fusion:
A General Guide
Determining Stature
Forensic scientists can estimate a person’s
stature (height) by examining one or more of
the long bones. Men and women have
different proportions of long bones to total
height.
Forensic Anthropology
3. Determination of Stature
• Long bone length (femur, tibia, humerus) is proportional to height
• For example, imagine from a skull and pelvis you determined the individual was an adult Caucasian, the height would be determine by:
• Humerus length = 30.8 cm
• Height = 2.89 (MLH) + 78.10 cm= 2.89 (30.8) + 78.10 cm
= 167 cm (5’6”) ± 4.57 cm
* See page 371 in your book
4. Other Information We Can Get
From Bones:• Evidence of trauma (here
GSW to the head)
• Blunt force has more
radiating cracks
• Evidence of post mortem
trauma (here the head of
the femur was chewed
off by a carnivore)
• Post mortem breaks
crack perpinducular to
length of bonehttp://library.med.utah.edu/kw/osteo/forensics/index.html
Other things we get from bones
• DNA – mitochondrial
• Facial Reconstruction
– Markers on the skull are measured and you
can determine thickness and shape of muscle
– Computer programs now do the math for us.
We can adjust variables such as nose length,
hairline, skin color, etc.
Sources:
• A very good website with photos and information on forensic anthropology (including estimating age, stature, sex and race):– http://library.med.utah.edu/kw/osteo/forensics/index.ht
ml
• A good site with a range of resources:– http://www.forensicanthro.com/
• Another good primer for determining informtion from bones:– http://www.nifs.com.au/FactFiles/bones/how.asp?page
=how&title=Forensic%20Anthropology
• Great, interactive site:– http://whyfiles.org/192forensic_anthro/
Bag O’ Bones Activity
Get Ready …
Get a long piece of butcher paper from your teacher.
Place it on the floor and have one of your classmates lay on it (back on the
floor). Use a marker to make an outline of your classmate’s body.
Make a Skeleton …
Take the bones out of the bag and place
them on the body outline in the approximate
location where they would be found. You
may refer to the skeleton model if you need
help identifying a bone or its location.
Measure the same person and draw their
skeleton. Lower of higher I will assign you.
Are you ready for a
challenge?
Bone Challenge
The Challenge … How fast can you put together a skeleton?
Directions:
1 - Find a partner and get a set of bones, blindfold, and timer from your
teacher.
2 – Put on a blindfold and then have your partner spread out the “bones”
on the table in front of you.
3 – When your partner starts the timer and says “go”, follow his/her
directions to put the skeleton back together.
4 – Record your time on your worksheet.
Who had the best time? _____________________