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? _____________________