Forensic Anthropology. What can it tell us?

Transcription

1 Forensic Anthropology What can it tell us?

2 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

3 Development of Bone All of our lives bone is deposited, broken down and replaced Osteocytes cells that form basic framework for new bone

4 Development of Bone Functions of Osteoclasts Osteoclasts 1. Specialized to dissolve and shape bone as you age 2. 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

5 Number of Bones Children 450 Children have bones that eventually suture together Adult 206 after all bones have fully developed

6 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

7 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)

8 Skulls Bones to Know Maxilla Mandible Zygomatic bone Vomer bone Frontal bone Nasal bone Orbit (eye socket) Sphenoid bone Sutures (between skull bones)

9 Skulls Male vs. Female Frontal View Male Trait Female Low and sloping Frontal Bone Higher and more rounded More Square More Square Thicker and larger Shape of Eye (orbits) Mandible (Lower Jaw) Upper Brow Ridge (Zygomatic) More Rounded More V-shaped Thinner and smaller

10 Skulls Male vs. Female Side View Male Trait Female Present Lower and more sloping Occipital protuberance Frontal bone Absent Bumpy and rough Surface of skull smooth Higher and more rounded Angled at 90 (straight) Mandible (Jaw bone) Greater than 90 (sloping)

11 Male Vs. Female Skull

12 Pelvis Male vs. Female Things to consider: Sub-pubic angle Length, width, shape, angle of sacrum Width of ileum Angle of sciatic notch

13 Pelvis Male vs. Female Male Trait Female degrees Subpubic angle Triangular pubis Heart shaped Longer, narrower, curved inward Shape of pubis Shape of pelvic cavity sacrum > 90 degrees Rectangular pubis Oval shaped Shorter, broader, curved outward

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15 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

16 Distinguishing Age Bones don t reach maturity at the same time To help tell their age: suture marks presence or absence of cartilage

17 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

18 Suture Marks Cont d Coronal Suture: closed by age 50 Lamboidal Suture: begins closing at 21 accelerates at 26 closed by 30

19 Long Bones When head of a long bone has fused with shaft completely indication of age Each bone takes different amount of time

20 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) cm 2.10(49) = cm or 69 inches (5 9 )

21 Distinguishing Race 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 Becoming less significant.why?

22 Shape of Eye Orbits Nasal Spine Distinguishing Race Caucasoid Negroid Mongoloid Rounded, somewhat square Prominent spine Rectangular Very small spine Rounded, somewhat circular Somewhat prominent spine Nasal Index <.48 > 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

23 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

24 Mitochondrial DNA degrades much, much, much slower Can be extracted from bones and compared to living relatives on mother s side of family DNA Evidence

25 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

26 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