Forensic AnthropologyChapter 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• 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 GenderMales

• 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 V-

shaped– No occipital protuberance

Male vs. Female Pelvis

Region Bone Male Female

Pelvic 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

• 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