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Forensic Anthropology

Forensic Anthropology

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Forensic Anthropology

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  1. Forensic Anthropology

  2. What Questions Can Forensic Anthropology Answer? • Race • Sex • Approximate age • Approximate stature • Pathologies (diseases) • Traumas (injuries) • Other individual traits

  3. 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) • How many bodies? • How long dead? - recent or ancient (e.g. construction or digging at an old burial site) • Cause of death?

  4. How does this Work? • Regression equations used 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."

  5. Sex Estimation • The sex of an individual is 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.

  6. 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

  7. Sex Estimation – long bones • 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 (Bass). • Much more difficult to estimate sex in children’s skeletons.

  8. 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.

  9. Other femur features

  10. Sex Estimation: Skull • Good area for sex determination • Generalization: male skull more robust, muscle-marked than female, but ABSOLUTE DIFFERENCES SELDOM EXIST • Sex estimation: face, mandible, vault

  11. Sex Estimation: Face 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.

  12. Pelvis • The pelvis of a woman is wide and circular whereas 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.

  13. Pubis Bone Traits Related to Sex

  14. Male Pelvis Subpubic Notch

  15. Female Pelvis Subpubic Notch

  16. Sciatic notch comparison – which is female?

  17. Determining Ages of Skeletons • Bone growth stops at about 20 yrs. of age in humans. • Adult bone continuously adapts to prevailing stresses by appropriate deposition and resorption. • Deposition and resorption are under hormonal control - integrated with regulation of blood calcium levels.

  18. 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

  19. 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. • Most sutures begin fusing no earlier than 18 years of age

  20. Skull Sutures

  21. Fused sutures in adult

  22. The Teeth • The teeth are arranged in upper and lower arches. Those of the upper are called maxillary; those of the lower are mandibular.

  23. There are four types of teeth with very different shapes: • Incisors (2) • Canines (1) • Premolars (bicuspids) (2) • Molars (2-3) • Individual teeth are quite distinct, even when lost from a jaw.

  24. Dental Formula (from the midline) • Primary (deciduous) teeth. • incisors, two upper and two lower; • canines, one upper and one lower; • molars two upper and two lower equals ten per side. • Permanent teeth. • incisors, two upper and two lower; • canines, one upper and one lower; • premolars, two upper and two lower; • molars, three upper and three lower.

  25. 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.

  26. 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 erupt.

  27. Baby Teeth Permanent Teeth Incisors: 7-12 months Incisors: 6.5 years Canines: 2 years Canines: 10.8 years Premolar 1: none Premolar 1: 10.4 years Premolar 2: none Premolar 2: 11 years Molar 1: 3 years Molar 1: 6.2 years Molar 2: 3 years Molar 2: 12.2 years Molar 3: none Molar 3: 18 years

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

  29. Dental Disease - Cavities, Abscesses, and Attrition

  30. 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.

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

  32. Growth areas of the long bones (epiphysis) • From birth to ±25 years of age, a person grows at a relatively constant rate. • Growth takes place at the ends of the long bones. • At a certain age, growth is completed and this can also be seen on the bone.

  33. Epiphyseal Fusion • The pattern of fusion of bone ends (epiphysis) to bone shaft (metaphysis) in each bone indicates age. • The upper arm stops growing at the shoulder at approximately age 20 and at the elbow at approximately age 14.5. • The upper leg stops growing at the hip at approximately age 17.5 and at the knee at approximately age 18.

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

  35. Height • An intact corpse can be measured, but a disarticulated or incomplete skeleton has to be pieced together. • Stature • 3.26 x (humerus) + 62.10 = stature +/-4.43cm • 3.42 x (radius) + 81.56 = stature +/-4.30cm • 3.26 x (ulna) + 78.29 = stature +/-4.42cm • (there will be 2 calculations for stature, based on the upper and lower margin of error)

  36. Race or Ethnic Group Determination • The skull is the only reliable bone. • Caucasoid (all whites) • Negroid (all blacks - African, African Americans and West Indians) • Mongoloid (Chinese, Japanese, American Indians)

  37. In Caucasoids: Nasal openings are narrow. Face is flatter

  38. In Mongoloids “Shovel-shaped" concave upper incisor teeth. Cheekbones (Zygomatic arches): are wider and more prominent. Greater width between eyes.