Forensic Anthropology - 10/27

Forensic Anthropology

  • Forensic Anthropology - Application of anthropological principles to legal and criminal investigations

    • more recently deceased

  • Similar to Bioarcheology - Study of human remains from archaeological context

    • Both are osteology specialists that focus on the skeleton

Identifying Human Remains:

  • Is it bone?

  • Is it human?

  • Is it modern or archaeological?

  • How many individuals are present?

  • Who are they?

    • estimation of age

    • estimation of sex

    • estimation of ancestry

  • Did trauma occur before or close to/after death?

  • What happened to the remains after death?

Initial Skeletal Analysis - Is it bone?

  • Challenges to identifying bone:

    • Bone many be fragmentary

    • Other materials can be mistaken for bone

  • Clue: Teo distinct layers

    • Dense compact (cortical) bone

    • Inner spongy (trabecular) bone

Is it Human?

  • identifying the bone by size and shape is an important tool

  • Human bones

    • clear distinction between spongy and compact layers

    • compact layer is often thinner than in animals

Modern vs. Archaeological (or Paleontological)

  • Alongside whether a bone sample is human or animal, determining if the sample belong to a modern versus an archaeological or paleontological context is critical

  • Outside of chronometric dating, the context of the find, and evidence from the bones themselves may help make the distinction

    • Dental filings and wear

    • Evidence of surgery

    • Artifacts or other material evidence

How many individuals are present?

  • Estimate the number of individuals in a burial assemblage

    • Mass graves or commingled burials

    • Multiple methods

    • Most commonly used method in Minimum Number of Individuals (MNI)

  • MNI methodology:

    • Collect all bones from a site

    • categorize the bones by type and size (correlated to estimated age and sex)

    • determine for each group the minimum number of individuals required to account for available bones (ex: # of femurs)

Constructing the Biological Profile - Age

  • 2 methods measure growth and development

    • Epiphyseal union: appearance and closure and epiphyses

    • Dental development

      • 20 deciduous teeth

      • 32 adult teeth

      • Erupt on a regular schedule

Four Stages of Epiphyseal Fusion

  • Phase 1 (or phase 0) - Non fusion

  • Phase 2 - appearance

  • Phase 3 - Partial fusion

  • Phase 4 - Complete fusion

Constructing a Biological Profile - Sex

  • Pelvis and skull used most often

  • Adults exhibit sexual dimorphism

  • Metric vs. non-metric traits

  • Sex vs. Gender

  • Cranial features tend to be more robust in males

    • Robust - larger in size and thickness

  • during puberty, estrogen causes a widening of the female pelvis for childbirth

  • Phenice method looks at these features

  • Sex vs. Gender

    • In anthropology, one’s biological sex and one’s gender expression are considered to be separate-but-intertwined elements of personal identity

    • Gender expression can take many forms, especially cross-culturally, some of which will not necessarily be evident in skeletal structure, and some of which may very well be apparent

    • Hormone replacement therapy depending on the age may shape sex-based characteristics of the skeleton toward that the experience gender. Likewise, surgeries to alter appearance to match that of the experienced gender may involved alterations to bone structure

Constructing the Biological Profile - Ancestry

  • Biological ancestry refers to genetic differences between modern populations

    • challenge - human biological races don’t exist

  • Human populations vary

    • Environmental forces

    • Biological clues may predict ancestral origins

  • Metric traits

    • FORDISC program

    • Non-metric (observable) traits

    • Cranium is the best area to use

Constructing the Biological Profile - Stature 

  • Measure bones that contribute to overall height 

    • Long bones of leg

  • Use mathematical equation to predict stature

Identification - Individualizing Characteristics

  • Biological profiles and scene context narrow the list of potential presumptive identifications

  • Positive identifications are based on traits unique to the individual

    • Medical and dental radiography

    • Surgical Implants

Trauma

  • trauma is an injury to living tissue caused by an extrinsic force or mechanism

  • May reflect:

    • Day-to-day life

    • Interpersonal injury

    • Trauma associated with the death event

Antemortem, Perimortem, and Postmortem

  • Antemortem (sometimes premortem) - indicating trauma or injury that occurred prior to death - determined by signs of healing

  • Perimortem - indicating trauma around the time of death - often not easily distinguishable from postmortem findings

    • Neither perimortem nor postmortem trauma will show evidence of healing. Perimortem injuries may or may not be directly related to the cause of death

  • Postmortem - indicating damage that occurs after the point of death

Trauma Analysis - Types of Trauma

  • Sharp force - includes linear incisions created by a sharp straight edge, punctures, and chop marks

  • Blunt force - crushing, breaking injuries produced by low-velocity impact over a larger area

  • Projectile - Penetrating wound at high velocity (gunshot)

  • Thermal - bone exposure to high heat

Sharp Force Trauma

  • V-shaped cuts - sharp tools or weapons

  • U-shaped cuts - predator teeth or claws

Taphonomy

  • Taphonomy - the study of what happens to remains after they have been deposited (after death)

  • Examples:

    • Rodent gnawing

    • Carnivore damage

    • Burned bone

    • Root etching

    • Weathering

    • Cut marks

Fossilization

  • For a relatively rare percentage of human remains (_<1%), fossilization will occur which transforms the organic tissues of bone into minerals (permineralization)