Download Forensic Anthropology Chapter 13 Anthropology: Scientific study of

Forensic Anthropology
Chapter 13
Anthropology: Scientific study of all aspects of human development and interaction
– Tools, language, traditions, social interactions, how we relate to societies
– Physical anthropology: studies these identifying characteristics on the remains of an
individual
• Can be used to determine the sex, race, height, and physical health of a victim
from his or her remains
Forensic Anthropologist
• Determines identity of the deceased
• Works with Forensic Pathologists and Forensic Odontologists to determine cause and manner
of death and estimate PMI (postmortem interval)
• Compares skeletal traits to antemortem (before death) traits, if available
Duties of Forensic Anthropologist
• Identify skeletal remains
• Collect skeletal remains
• Assist at mass disasters
• Facial reconstruction of deceased individuals
• Use technology to superimpose faces on skulls
• Assist in identification of live individuals by facial/body recognition and analysis of gait
History of Forensic Anthropology
• 1800s – scientists began to use skull measurements to differentiate among individuals
• 1932 – first FBI crime lab, partnered with Smithsonian Institution for identification of human
remains
• 1939 – William Krogman published the Guide to the Identification of Human Skeletal Material
• WWII soldier remains identified using anthropologic techniques
• New techniques in DNA found in the mitochondria of cells of bones has been used in
identification
Characteristics of Bone
• Originate from osteoblasts
– Begin as soft cartilage in fetal development
– Osteoblasts migrate to the center of cartilage production and deposit minerals
(calcium phosphate) for ossification (formation of bone) during fetal development
– Outline of skeleton formed by 8th week of pregnancy
• Bone is surrounded by a protective tissue called periosteum – keeps bones moist and aides in
repair of injuries
• Bone is constantly deposited, broken down, and replaced
– When bone is broken, blood vessels at the area have the ability to increase calcium
phosphate deposition to help heal the break
• Osteocytes: newly trapped osteoblasts that form the new bone framework
– No longer produce new bone
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Osteoclasts: specialized to dissolve bone (secrete enzymes)
– Help in reshaping bone
– Aid in maintaining homeostasis within the body (calcium levels)
– Remove cellular wastes and debris from the bones
How many bones in the human body?
– __________________ as an adult! Baby: _________________
Joints: Location where bones meet (articulate)
• Three kinds of connective tissue:
– Cartilage – wraps ends of bones for protection, prevents
friction between bones
– Ligaments - connect two or more bones
– Tendons - muscle to bone
Aging of Bones
• Children build bones faster than bones deteriorate
• After 30 years, bones deteriorate faster than they are built
– Can be slowed with exercise
• Osteoporosis – bones lose calcium and break easily due to being porous
– Vertebral collapse
• # of bones and their condition can tell an investigator about a person’s age, health, and
whether they had enough calcium
Skeletal Identification
• Every Human Skeleton is Unique
– Genetics—stature, race and gender
– Growth—rate of growth differs in individuals
– Use/Age of Skeleton—wear and tear due to
occupation and/or aging
– Injury or trauma—fractures or surgical scars
• Forensic examination of remains begins by answering
these questions:
1. Is material bone?
2. If it is bone; is it human?
3. Does the age of the bone make it useful for
forensic purposes?
Osteobiography
• Begins with identification of class characteristics, which
allows sub-grouping of remains
• Class Characteristics
– Age, Gender, Race, Stature
• Individual characteristics such as injury to a bone or
unique dental work may also be identified
– X-rays during autopsy shows previous fractures,
artificial joints, pins – help link to identity
Differentiating Gender
Males
• Thicker, rougher, appears bumpy
(robust)
• Skull:
– Frontal bone low and sloping
– Eye orbits square
– Lower jaw more square, angled
at about 90 degrees
– Squarer chins
– Occipital protuberance
Females
• Smoother and less knobby (gracile)
• Skull:
– Frontal bone higher and more
rounded
– Eye orbits more circular
– Lower jaw is sloped with an angle
greater than 90 degrees
– Chin rounder and more Vshaped
– No occipital protuberance
Male vs. Female Pelvis
Region
Pelvic
Bone
Male
Female
Subpubic angle
50-82 degrees
90 degrees
Shape of pubis
Triangular pubis
Rectangular pubis
Shape of pelvic
cavity
Heart-shaped
Oval-shaped
Sacral
Sacrum
Longer, narrower,
curved inward
Shorter, broader, curved
outward
Femur
Femur (thigh bone)
Straighter angle in
relation to pelvis
Greater angle in relation
to pelvis
Distinguishing Age
• Look for presence or absence of cartilage
• Suture marks
– Joints of skull
– Immature skull: fontanels
– Sutures gradually disappear –
smoother appearance with age
– Distinguishing Age
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Cartilaginous lines
– 450 bones  206 bones through life
– Epiphysis – cartilaginous line while bones are growing
• No longer visible after cartilage is fully replaced (happens earlier in
females than males)
• Age for completion of each bone varies – helps to approximate
age from bones
– Once growth ceases, only repairs and reactions to aging appear
Long bones
– Head of bone fused to shaft indicates age
– Fusion occurs at different times with different bones
Estimate of age may be determined by assessing formation of teeth and eruption through
gums
Pubic & Rib Bones
– Macroscopic examination of interior edge of pubic symphysis allows for determining
age at death—the smoother the surface, the older the bone
– Sternal ends of ribs change as person gets older: increased pitting and presence of
projections, and changes in type and quality of bone
Estimating Height
• Measurements of long bones
– Arm: humerus, radius, ulna
– Leg: femur, tibia, fibula
– Databases using mathematical relationships
– Varies depending on race and bones used
– More accurate if race and sex are known
• Estimating Height Example:
A femur measuring 49 cm belonging to an African
American male is found. Use the formula to estimate
his height.
(cm inches = cm/2.54)
Distinguishing Race
• More difficult as interracial marriages have caused blending of physical traits
• Skeleton does not contain many obvious characteristics that define racial characteristics
• Best indicated by bones of skull
– Shape of eye sockets
– Absence or presence of a nasal spine
– Measurements of the nasal index (ratio of the width of the nasal opening to the height
of the opening, multiplied by 100)
– Prognathism (projection of the maxilla beyond the mandible)
– Width of face
– Angulation of the jaw and face
Other Clues
• Right-handed vs. left-handed
• Diet and nutritional information (i.e. lack of Vitamin D or calcium)
• Diseases and genetic disorders (i.e. osteoporosis, arthritis, scoliosis, osteogenesis imperfecta)
• Type of work or sports based on bone structure
• Surgical implants (artificial joints, which have code numbers, and pins)
• Childbirth
DNA Evidence
• DNA profiling typically uses nuclear DNA (in nucleus of white blood cells and other body
tissues)
• Bones contain little nuclear DNA due to degradation, but do contain mitochondrial DNA
– Mitochondria contain DNA inherited from mother (no genetic information from father in
mitochondria)
– Can be extracted from bone and profiled
– Compared with living relatives on the mother’s side of the family to determine identity
Skeletal Trauma Analysis
• attempts to make distinctions between the patterns caused by weapons and the damage
and wear caused by the environment or animals after death
• Attempt to determine weapon that caused death
– Sharp-force and blunt-force trauma, gunshots, and knife wounds all have distinctive
shatter patterns
– Blunt objects have more cracks radiating from the site of impact – as well as causing
more damage to the surface of the bone
• Bone breaks: strength of bone decreases as it ages and dries out, while living bone is more
flexible and breaks in different ways
– Living bones shatter in a spiral pattern parallel to the length, old bones often break
perpendicular to the length
Cases