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