Osteology and Forensic Anthropology Reminder: Homework due one week from today

Happy Birthday Mary Leakey! 1913-1996

Osteology The scientific study of bones. Comes from the Greek word “Osteon,” meaning “bone” Sub-discipline of archaeology (anthropology), anatomy, forensics etc.

Why should we care? What bones can tell us about an individual: Age at death Height/stature Biological sex Health Habits Cause of death Ancestry

Why should we care? What bones can tell us about a population: Overall health patterns Overall age expectancy Gender or class specific work patterns “Human skeletal remains are a unique source of information on the genetic and physiological responses our ancestors made to the challenges posed by past natural and sociocultural environments.” –Phillip Walker, Bioarchaeological Ethics, 2000

Types of Bone cells Bone is formed and metabolized by specific cells and is in a constant state of remodeling. Osteoclasts: Bone destroying cells Osteoblasts: Bone generating cells Osteocytes: Mature bone cells; “spider” shaped, maintains bone tissue.

The Human Skeleton Skull: mandible and cranial bones. Axle skeleton: vertebral column, clavicle, sternum and ribs, pelvic bones. Long bones: limbs (arms and legs). There are 206 bones in a mature human skeleton.

The Human Skeleton Proximal v. distal Sagittal plane: cuts through the body front to back, divides body into left and right halves. Transverse plane: divides body at the waist into upper and lower halves.

The Human Skeleton

The Individual How to determine age: Macroscopic: Microscopic: Changes we can see with the naked eye. Microscopic: Requires the use of a scanning microscope. Dental development and eruption. Eruption starts anterior to posterior. Dental development in children is very precise.

The Individual How to determine age: The growth rate of bones can tell us (roughly) how old someone is. Fusion/ossification = when bones develop, or fuse. Osteons Wear on bones and teeth. Bones most often used: teeth, humerus, cranium (cranial sutures), pubic symphysis .

The Individual How to determine age: Determining age really only works until about age 65 (macroscopically). Cortical remodeling works as an age determinate until about age 75 (microscopically)

The Individual How to determine sex: Determining the biological sex of subadult is much more difficult than in mature skeletons, and many times impossible. “robust” vs. “gracile” as a means of determining male versus female. Bones most often used: pelvic bones, mandible, cranium.

The Individual Health/habits: (Paleo)pathologies Infectious diseases of bone Wear patterns on bones Status or class markers

Evidence of iron deficiency anemia in cranial bone.

The Individual Advanced arthritis of the spine (lumbar vertebrae).

The Individual Tooth wear and decay

The Individual Infectious disease: Although an infection my lead to death it may not detectably alter bone. Those that do though, often leave lesions (a few examples of diseases which do leave a telltale mark on bone: smallpox, leprosy, histoplasmosis) Osteitis: inflammation of bone due to infection.

Wear pattern on scapula and humerus Also, if an individual is a weight lifter, runner, etc, that will be represented on the skeleton as well.

Isotopic Analysis or You are what you eat Stable isotope analysis: is the analysis of stable (nonradioactive) isotopes of elements (like carbon) that provides information about ancient diet. Strontium isotope analysis: the analysis of strontium, which come from water, to determine where an individual lived during their lifetime. Isotopes: are variants of a particular chemical element (Example: C-12, C-13, and C-14 are three isotopes of carbon

The Population Overall health of a population Example: A Maya population at Copan, in Honduras, experienced a lot of anemia during the late Classic and early Post Classic periods (750-1200). Therefore, they were not getting enough iron.

The Population Class or gender roles: Wear on bone can illustrate that some jobs were more likely men or women. Example: in many Pre-Columbian societies, the grinding of maize (corn) was a woman’s job. We know this through osteological evidence from female skeletons.

The Population Indicators of status in society: for example, the ancient Maya incised and filed teeth as a marker of high or elite status.

The Population Funerary archaeology How and where bodies are buried What artifacts are buried with them. Tells us a lot about a population.

Forensic Anthropology

Forensic Anthropology Forensic anthropologists apply standard scientific techniques developed in physical anthropology to identify human remains, and to assist in the detection of crime.

Forensic Anthropology Osteological techniques as applied legal settings. most often in criminal cases involving advance stages of decomposition. There are not many people who identify themselves solely as forensic anthropologists. http://www.physanth.org/ (American Association of Physical Anthropologists) http://www.theabfa.org/ (American Board of Forensic Anthropologists)

Cause and Manner of Death Cause of death: the disease or injury responsible for the sequence of events. Very specific. Manner of death: explains how the cause of death arose (example: natural vs. violent; accident, homicide, suicide etc).

Skeletal Trauma Fractures (stress, pathological, etc) Blunt force trauma Sharp force trauma Projectile Trauma

Key Terms Postmortem: occurred after death. Perimortem: occurred near or at time of death. Antemortem: occurred before death.

Key Terms Skeletal Trauma Remodeling Taphonomic changes: the process of the archaeological record. “Taphos” = Greek for death.

So how do we tell the difference???

Living vs. Dead bone In living bone the moisture content is high. Collagen (what gives bone its elasticity) is somewhat flexible. This allows for a certain degree of bending under stress. With decomposition, moisture is lost, collagen degrades and the bending capability is lost. Bone frails or snaps when subjected to trauma.

Postmortem changes to bone Roots. Tooth marks on bone. Carnivore = depressed fractures. Rodent = line fractures.

Blunt Force Trauma Any injury cause by a force that has a wide are of impact on bone. Usually bones with BFT exhibit both discontinuities and fracture lines. Outbending and inbending on crainial injurys. Blunt force trauma to the left temporal bone.

Sharp Force Trauma Results from compression, shearing, etc. “chop marks,” “punctures,” “incisions.” Caused by knives, axes, ect. Sequence can usually not be determined.

Projectile Trauma Very distinct. Directionality of force is usually very clear. Speed is of projectile is a factor. Starts small, becomes wider as it passes through bone. So, exit wounds are generally larger than entry wounds.

Projectile Trauma Keyhole wounds: when projectile grazing the bone on entry or exit. Creates a “keyhole” shape

Miscellaneous Trauma Strangulation: breaks the hyoid bone.

Congenital perforation of the sternum: Though it looks like a bullet hole, it is actually a hereditary marker.

Additional Information Bone Voyage, by Stanley Rhine Kathy Reichs The Bone Woman, by Clea Koff The Human Bone Manual, by White and Folkens