1. Forensic Anthropology: Studying Bones1

2. Forensic Anthropology
The use of knowledge of the skeletal system to identify crime victims and determine cause and circumstance of death. 2

3. Forensic Anthropologist
Specializes in
hard tissue morphology
structure and variability
Dealing with bone

4. Archeologist, Pathologist – How Are They Different?
trained to analyze soft tissue and organs.
Their experience with hard tissue (bone) is limited.
Archeologist-
studies human cultures
looks at artifacts
jewels
pottery
architecture
bones - draw upon a knowledge of anthropology

5. What Questions Can Forensic Anthropology Answer?
What is the race of the individual?
What is the sex of the individual?
What is the age of the individual?
What is the stature of the individual?
What pathologies did the individual have?
What traumas did the individual have?
What individual traits did the individual have?

6. A Caveat
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)
Imprecise
Due to variation
Nevertheless, differences do exist and the more features you survey, the more precise your conclusions will be

7. Identity of Decomposed or Skeletal Remains
Are the remains human or animal? (butchers remains and skeletal remains of dead pets etc. may be found in unlikely places)
Are they really bones? (wood, stones)
Are they human?
How many bodies?
How long dead? - recent or ancient (e.g. construction or digging at an old burial site)
Cause of death?

8. What Can We Learn? Determination of Sex Determination of Race
Pelvis
Skull
(Long Bones)
Determination of Race
Approximate Age
Growth of long bones
Approximate Stature
Length of long bones
Postmortem or antemortem injuries
Postmortem interval (time of death) 8

9. The bones we’re interested in
Skull
The bones we’re interested in
Humerus
Pelvis
Femur
Tibia 9

10. How does this Work? Forensic anthropologists use
regression equations to determine
sex, age, stature, and race of skeletal remains.
Regression equations are
mathematical equations developed from
studies of bones of individuals of known sex, age, race, and stature, and are used to predict such things of even fragmentary skeletal remains.

11. Sex Estimation
Determined, when soft tissue is not present, by a number of skeletal indicators.
The more indicators used to determine sex, the more accurate the results.
A forensic anthropologist is analytically limited by the bones present and the condition of the bones.

12. Bones of men are larger and more robust than bones of women.
In general, the muscles in a man are stronger and more developed than in a woman.
Bones of men are larger and more robust than bones of women.
Some bones display specific features which can be used to help determination of the sex of the skeleton. The best indicators are the:
Skull
Pelvis
Head of the Femur

13. Sex Estimation – Adult Usually related to size in adult long bones
Male bones: usually larger, longer in a single population – be cautious if different populations are involved
Maximum diameter of head of humerus and head of femur may be used
Much more difficult to estimate sex in children’s skeletons.

14. Sex Estimation: Skull
1. Supraorbital (Brow) ridges: more prominent in males
2. Superior orbital margin: sharper in females
3. Palate: larger in males
4. Teeth: larger in males
5. Mastoid process: more prominent and rugged in males.
6. Orbit (Eye socket): Rounder in females, more rectangular in males
7. Chin: more pronounced in males and larger jaws.

16. 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) 16

19. Sex Determination: Pelvis
Women give birth
the pelvis of a woman is larger than the pelvis of a man.
The pelvis of a woman is wide and circular
the pelvis of a man is narrow and heart-shaped.
Two angles, the sub-pubic angle and the sciatic notch, cause the differences in the shape of the pelvis.
In women, the sub-pubic angle and sciatic notch are wide.
In men, the sub-pubic angle and sciatic notch are narrow.

20. Sex Determination - Pelvis
Sub-Pubic Angle
Pubis Body Width
Greater Sciatic Notch
Pelvic Cavity Shape 20

21. Male Pelvis Subpubic Notch

22. Female Pelvis Subpubic Notch

25. Sex Determination: Head of the Femur
In men, the diameter of the head of the femur is larger than 51 mm.
In women, the diameter of the head of the femur is less than 45 mm.

26. Determination of Sex: Long Bones
Normally, the long bones alone are not used alone 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 mm, while it is mm in males 26

27. Determination of Race Difficulties
3 race system is broad: Caucasian (European), Mongoloid (Asian), and African (African and West Indian).
Some will have traits completely inconsistent with their geographic origin.
Mixed-racial ancestry
Some exhibit characteristics of more than one racial group.
Indicators are not measurable and are therefore subjective.
Despite these drawbacks, race determination is viewed as a critical part of the overall identification of an individual's remains. 27

28. Caucasian, Mongoloid, African28

29. Features of the Skull Used in Race Determination
Nasal index:
The ratio of the width to the height of the nose, multiplied by 100
Nasal Spine
Feel the base of the nasal cavity, on either side of the nasal spine – you will feel sharp ridges (nasal silling), rounded ridges, or no ridges at all (nasal guttering)
Prognathism: extent of lower jaw
Shape of eye orbits (round or square
Nasal spine 29

30. Nasal Silling and Guttering30

31. General Shapes of the Eye Orbits31

32. Determination of Race: Caucasian
Nasal spine:
Prominent
Progathism: straight
Orbital openings:
round
Determination of Race: Caucasian
Trait
Nasal Index:
<.48
Nasal Spine:
Prominent spine
Nasal Silling / Guttering:
Sharp ridge (silling)
Prognathism:
Straight
Shape of Orbital Openings:
Rounded, somewhat square 32

33. Determination of Race: Mongoloid
Trait
Nasal Index
Nasal Spine
Somewhat prominent spine
Nasal Silling/ Guttering
Rounded ridge
Prognathism
Variable
Shape of Orbital Openings
Rounded, somewhat circular 33

34. Determination of Race: African: (everyone of African decent and West Indian decent)
Trait
Nasal Index
>.53
Nasal Spine
Very small spine
Nasal Silling/ Guttering
No ridge (guttering)
Prognathism
Prognathic
Shape of Orbital Openings
Rectangular or square 34

35. Determining Ages of Skeletons
Bone growth stops at about 20 yrs. of age in humans.
Adult bone continuously adapts to prevailing stresses
Bone density changes with age depending on calcium levels

36. Skeletal Age Skeletal age is the estimated age at which a person died.
Skeletal age can be determined by looking at the following:
sutures of the skull
teeth
ribs
vertebrae
growth areas of the long bones: epiphyses

37. Sutures of the Skull When a baby is born, the skull is still growing.
To accommodate this growth, the different bones of the skull are separate.
By the age of 7, all the different bones have finished growing and the fontanelles have disappeared.
Fontanels are known as soft spots

38. Skull Sutures

39. Age Determination: Use of Teeth 39

40. Teeth
The first teeth to appear are the incisors, which are followed by canines and molars.
When chewing food, teeth grind down.
Comparing different teeth gives an idea of how long the teeth have been used.
Eventually teeth may be lost, due to caries or attrition.

41. X-Rays Are Used to Date Skulls
This is the side view of the dentition of a six year old boy.
There is still some variation from person to person in the order in which the teeth come in.

42. Teeth with 6 year molars
Baby Teeth
Teeth with 12 year Molars
Teeth with Wisdom Teeth

43. Dental Disease - Cavities, Abscesses, and Attrition

44. Age Determination from Skeleton
Long bone length (femur, tibia, humerus) is proportional to height.
Tables are used.
Fairly reliable up to the age of epiphyseal fusion.
There are sex, race, nutrition and personal variations to consider.

45. Determining Ages of Skeletons
Cranial suture fusion is less reliable.
Pubic symphysis changes slightly with age.
Arthritic changes and osteoporosis give further clues.

46. 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 46

47. Ossification Centers Useful only in fetuses and babies.
May be determined radiologically or by cutting into ossification centers.
May be confirmed histologically.
Most important center in medico-legal work is the distal center of the femur.
This is present at birth and indicates a full term baby.

48. As a child grows the epiphyses become calcified (turn to hard bone)
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)
From birth to ±25 years of age, a person grows at a relatively constant rate. 48

49. Epiphyseal Fusion: A General Guide49

51. 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. 51

52. Age Determination: Ribs
Because of breathing, the front part of the ribs is constantly moving.
As a person gets older, the front part of the ribs begin to change and form bony spikes.

53. Age Determination: Vertebrae
As a person gets older, bony spikes can also start growing on the vertebrae.
This starts at approximately 40 years of age.

54. Arthritic changes and osteoporosis give further clues to the ages of skeletons.

55. Determination of Age from Bone: Signs of wearing and antemortem injury
Occupational stress wears bones at joints
Surgeries or healed wounds aid in identification 55

56. Determination of Stature
Long bone length (femur, tibia, humerus) is proportional to height
Tables that forensic anthropologists use (but these also depend to some extent on race)
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 determined by:
Humerus length = 30.8 cm
Height = 2.89 (lenth of humerus) cm
= 2.89 (30.8) cm
= 167 cm (5’6”) ± cm 56

57. Individual Characteristics
Fractures
Head Injuries

58. Individual Characteristics
Bone disease (Paget's disease, tumors)
Previous injury to bone (fracture callus, prosthesis, metallic fragments).
Comparison of trabecular pattern of bone.
Pattern of skull's frontal air sinuses. Outline is unique and comparisons with clinical X-rays are useful.

59. 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) 59

60. Sources:
A very good website with photos and information on forensic anthropology (including estimating age, stature, sex and race):
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A good site with a range of resources:
Another good primer for determining informtion from bones:
e=how&title=Forensic%20Anthropology
Great, interactive site: 60