Forensic Anthropology:

Studying Bones

Cranium

Cervical Vertebrae

Sternum

Humerus

Ulna

Radius

Carpals

Metacarpals

Phalanges

Sacrum

Tibia

Fibula

Tarsals

Metatarsals

Phalanges

Clavicle

Scapula

Ribs

Lumbar Vertebrae

Ilium

Ishium

Femur

Patella

Directions:

Identify the bones.

Osteology: Study of Bones

• Each bone studied INDIVIDUALLY

Osteology

Osteology

Forensic Anthropology:

-The study of human skeletal remains to determine sex, age,

race, and time of death in an effort to identify an individual.

- It includes newer topics of facial reconstruction and age

progression.

- “anthropo” is Greek for humankind or man, logos means

“the study of”.

A Caveat Before we Start:

• Informative features about the age, sex, race and stature of individuals based on bones is based on biological differences between sexes and races (males are generally taller and more robust) as well as differences due to ancestry (certain skeletal features of the skull).

• However, it is imprecise because so much human variation exists and because racial differences tend to homogenize as populations interbreed.

• Still differences do exist and the more features you survey, the more precise your conclusions would be.

What Can We Learn?

• Determination of Sex – Pelvis

– Skull

• Determination of Race – Skull

• Approximate Age – Growth of long bones

• Approximate Stature – Length of long bones

• Postmortem, perimortem or

antimortem injuries.

1. Determination of Sex • Pelvis is the best bone (differences due to

adaptations to childbirth):

females have wider sub-pubic arch angle.

females have a sciatic notch > 90°

females have a broad pelvic inlet

1. 1.

1.

2. 2.

2.

3. 3.

3.

Determination of Sex

• Pelvis best (another view)

females have wider subpubic angle

females have a broad, shovel-like ilium

females have a flexible pubic symphysis

1. 1.

2. 2. 3.

1.

2.

3.

Information from skeletal remains Sex of decedent

Male Female

Determination of Sex

Cranium second best, Pelvis = Best.

• Crests and ridges are more

pronounced in males (A, B, C, H).

• Chin significantly more square in

males (E).

• Jaw (I, E), mastoid process wide

and robust in males.

• Forehead slopes more in males (F).

Determination of Sex

• Normally, the long bones alone

are not used to estimate gender.

However, if these bones are the

only ones present, there are

characteristics that can be used

for sex determination.

• E.g. maximum length of humerus

in females is 305.9 mm, while it is

339.0 mm in males

Sex Determination - Skull

Trait Female Male

Upper Edge of Eye Orbit Sharp Blunt

Shape of Eye Orbit Round Square

Zygomatic Process

Not expressed beyond

external auditory

meatus

Expressed beyond external

auditory meatus

Nuchal Crest (Occipital

Bone) Smooth Rough and bumpy

External Occipital

Protuberance Generally Absent Generally present

Frontal Bone Round, globular Low, slanting

Mandible shape Rounded, V-shaped Square, U-shaped

Ramus of mandible Slanting Straight

2. Determination of Race • It can be extremely difficult to determine the true race of

a skeleton for several reasons: – First, forensic anthropologists generally use a three-race

model to categorize skeletal traits: Caucasian (European), Asian (Asian/Amerindian), and African (African and West Indian).

– Although there are certainly some common physical characteristics among these groups, not all individuals have skeletal traits that are completely consistent with their geographic origin.

– Second, people of mixed racial ancestry are common. • Often times, a skeleton exhibits characteristics of more than one racial

group and does not fit neatly into the three-race model.

– Also, the vast majority of the skeletal indicators used to determine race are non-metric traits which can be highly subjective.

• Despite these drawbacks, race determination is viewed as a critical part of the overall identification of an individual's remains.

Determination of Race

– A THREE-RACE model is used to categorize skeletal traits:)

• Caucasoid = Europe, North Africa, West Asian

• Mongoloid = East Asia, Arctic, Native Americans( North and South)

• Negroid = Sub-Saharan Africa

White, Asian, African

From: Beyers, S.N. (2005). Introduction to Forensic Anthropology

Two ways of determining race

of a skull • Empirical = measurable

– Cranial Index

– Facial Index

– Nasal Index

• Observational = non-measurable

– Eye Orbit Shape

– Mastoid Process size/projection

– Prognathism

Empirical Measurements taken on a skull

• Nasal Index: Nasal

breadth divided by nasal

height

• Nasal Breadth (mm)=

distance from alare to

alare (al).

• Nasal Height (mm) =

distance from naison

(n) to nasospinale (ns).

Empirical Measurements

• Cranial Index: the

ratio between cranial

breadth and cranial

height

– Breadth (mm) =

euryon (eu) to

euryon (eu).

– Height (mm) =

Glabella (g) to

Opistocranium (op)

Empirical Measurements • Facial Index: Facial

height divided by Facial

width

• Facial Height (mm) =

distance from nasion

(n) to gnathion (gn)

• Facial width (mm) =

distance from zygion

(zy) to zygion.(zy)

(width)

Non-measurable features of

skulls

• Nasal Spine: Bony

projection that sticks

out at the base of the

nose.

• The shape of nasal

spine varies between

races.

Nasal Silling and Guttering

Nasal Silling: the

bottom of the nasal

spine points outward

forming a “spout”.

Nasal Guttering:

lacking a sill at the

bottom of the nasal

aperture.

Non-measurable features of

skulls: Gonial Angle

• Gonial angle: The

angle of the jaw.

• Related to the face

shape

• Referred to as either

rounded or not

rounded.

Non-measurable features of

skulls: Shape of Mandible

• Mandible: The shape

of the jaw

• Referred to as either

rounded or squared.

Round or Squared?

Non-measurable features of skulls: Face Shape

• Prognathism: The

protruding of the

lower jaw.

• Most evident in

Negroid skulls.

• Orthognathism:

No protrusion of

lower jaw.

• Most evident in

caucasoid

skulls

Non-measurable features of skulls: Eye Orbit • Eye Orbit: The bony area surrounding an eyeball. Usually described as

one of four shapes using a combination of the descriptions below:

• Round or Squared

• Slanted or Not Slanted

General Shapes of the Eye Orbits

Determination of Race: Caucasoid/European

Trait

Cranial Index .75-.80

Nasal Index: Less than .48

Facial Index: Greater than .90

Nasal Spine: Prominant

Face Shape: Orthognathic

Eye Orbits Squared and

Slanted

Gonial Angle Slightly flared

Nasal spine:

Prominent

Orbital

openings:

round

Determination of Race: Asian/Mongoloid

Trait

Cranial Index Greater than .80

Nasal Index .48-.53

Facial Index .85-.90

Nasal Spine Small

Face Shape Variable

Shape of

Orbital

Openings

Rounded, not

slanted

Determination of Race: African (Negroid)

Trait

Cranial Index .75 or less

Nasal Index .53 or greater

Facial Index .85 or less

Nasal Spine Very small spine

Face Shape Prognathic

Shape of

Orbital

Openings

Rectangular and

straight

Trait Caucasoid Negroid Mongoloid

Cranial Index .74 -.79 .75 or less .80 or more

Nasal Index Less than .48 .53 or greater .49-.52

Facial Index Greater than

.90

.85 or less .86-.89

Facial Profile/Shape Orthognathic Prognathic Variable

Eye Orbit

Shape/Direction

Squared and

Slanted

Squared and

Straight

Rounded and

Straight

Gonial Angle Shape Slightly Flared

(a little over 90)

Straight (very

close to 90)

Flared (greater

than 90)

Chin Profile Pointed Flat Flat

3. 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

• The figures below are of the Epiphyses of the femur or thigh bone (the ball end of the joint, joined by a layer of cartilage).

• The lines in the illustrated Image 1 show the lines or layers of cartilage between the bone and the epiphyses. The lines are very clear on the bone when a person, either male or female is not out of puberty.

• In Image 2, you see no visible lines. This person is out of puberty. The epiphyses have fully joined when a person reaches adulthood, closing off the ability to grow taller or in the case of the arms, to grow longer.

Figure 1. Figure 2.

Epiphyseal Fusion:

A General Guide

Age at Death Long Bone Development

Determination of Age from Bone: Signs of

wearing and antemortem injury

Occupational stress wears

bones at joints Surgeries or healed wounds

aid in identification

Age Determination: Use of Teeth

4. Determination of Stature

• Long bone length (femur, tibia, humerus) is proportional to height

• There are tables that forensic anthropologists use (but these also depend to some extent on race)

• Since this is inexact, there are ‘confidence intervals’ assigned to each calculation.

• 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 your lab handout for more tables

BONE RACE MALE EQUATION FEMALE EQUATION

Femur

Caucasoid 2.32 x femur + 65.53 ± 3.94 cm 2.47 x femur + 54.10 ± 3.72 cm

Negroid 2.10 x femur + 72.22 ± 3.91 cm 2.28 x femur + 59.76 ± 3.41 cm

Mongoloid 2.15 x femur + 72.57 ± 3.80 cm (Use Male)

Tibia

Caucasoid 2.42 x tibia + 81.93 ± 4.00 cm 2.90 x tibia + 61.53 ± 3.66 cm

Negroid 2.19 x tibia + 85.36 ± 3.96 cm 2.45 x tibia + 72.56 ± 3.70 cm

Mongoloid 2.39 x tibia + 81.45 ± 3.24 cm (Use Male)

Fibula

Caucasoid 2.60 x fibula + 75.50 ± 3.86 cm 2.93 x fibula + 59.61 ± 3.57 cm

Negroid 2.34 x fibula + 80.07 ± 4.02 cm 2.49 x fibula + 70.90 ± 3.80 cm

Mongoloid 2.40 x fibula + 80.56 ± 3.24 cm (Use Male)

Humerus

Caucasoid 2.89 x humerus + 78.10 ± 4.57 cm 3.36 x humerus + 57.97 ± 4.45 cm

Negroid 2.88 x humerus + 75.48 ± 4.23 cm 3.08 x humerus + 64.67 ± 4.25 cm

Mongoloid 2.68 x humerus + 83.19 ± 4.16 cm (Use Male)

Ulna

Caucasoid 3.76 x ulna + 75.55 ± 4.72 cm 4.27 x ulna + 57.76 ± 4.30 cm

Negroid 3.20 x ulna + 82.77 ± 4.74 cm 3.31 x ulna + 75.38 ± 4.83 cm

Mongoloid 3.48 x ulna + 77.45 ± 4.66 cm (Use Male)

Radius

Caucasoid 3.79 x radius + 79.42 ± 4.66 cm 4.74 x radius + 54.93 ± 4.24 cm

Negroid 3.32 x radius + 85.43 ± 4.57 cm 3.67 x radius + 71.79 ± 4.59 cm

Mongoloid 3.54 x radius + 82.00 ± 4.60 cm (Use Male)

5. Other Information We Can Get

From Bones:

• Evidence of trauma (here

GSW to the head)

• Evidence of post mortem

trauma (here the head of

the femur was chewed

off by a carnivore)

http://library.med.utah.edu/kw/osteo/forensics/index.html

Medial Imposition

Sculpting By Angela Janick

What if this is all you have?

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Facial Reconstruction

• Determine demographic information

(female, Caucasian, early 40s)

• Note unique features

(had lost all back teeth on

upper and lower jaw)

• Anything known about this individual?

(came to U.S. by boat in 1710

from Europe, died and buried in

NY around 1733)

1. Obtain skull

Facial Reconstruction

2. Add tissue depth markers

• Based largely on sex and race

3. Begin to add common fat deposits

and underlying muscles

Facial Reconstruction

4. Add muscle to average

depth for race

5. Add skin, nose, ears

6. Add features related to age and race

(wrinkles, eye and hair color)

Facial Reconstruction

7. Add clothing etc appropriate for the

time period, religious affiliations, etc

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Forensic Anthropology and

Odontology

Human Bone vs. Animal Bone

• Macroscopic differences

• Radiology

• Observation

• Measurement

• Microscopic differences

CHE 113 69

Macroscopic differences

Baboon femur Human femur

Microscopic differences

Spongy bone

human

mouse

CHE 113 71

Other information TRAUMA and PATHOLOGIES

Ante- mortem

Post-mortem

Peri-mortem

Gunshot

CHE 113 72

Trauma

Individual Identification

Person identified when it

was found that the

amalgam used in her

dental restorations was of

a type found only in

specific areas on the

Eastern Coast of the

United States.

Habitual activity can wear away the

protective, cartilagenous lining which

reduces friction in joints. The humerus

in this photograph were in contact for

many years prior to this individual's

death. The surfaces are smooth and

shiny, indicating that the joint capsule

and cartilage had worn away, allowing

bone on bone contact in the cavity.