Forensic Anthro Final <3

Advantages of Macroscopic Analysis

Advantages of Macroscopic Analysis

Quicker, no special equipment, don’t need a complete skeleton/bone

Advantages of Osteometric Analysis

Osteometric is less observer error and less prone to bias

Purpose of Histology

Figuring out if a material is bone using analysis of the microscopic structure of tissues

Purpose of Radiography

Comparing antemortem and postmortem x-rays or CT scans using dental records, skeletal trauma, anomalies, pathologies, and variation in typical skeletal anatomy (trabecular bone patterns, morphology of bones, sinuses, sutures)

Distinguishing Human and Non-Human Bone

Morphology, including articular surfaces, features, landmarks, etc. and histology, which is the analysis of the microscopic structure of tissues

Distinguishing Contemporary and Non-Contemporary Bone

Taphonomic indicators [bone quality (light or heavy, greasy or dry, eroded, etc.), postmortem treatment [autopsy cuts, drill holes, etc.)], contextual clues (grave or surface scatter, personal effects, etc.), and biocultural factors (dental wear, surgical implantations, etc.)

Contributions of Forensic Archaeology

The death scene as an archaeological site; locating burials, sampling, mapping, excavation, recovery, and interpretation

Detecting Human Remains

Line search/pedestrian survey, look for surface irregularities (vegetation or soil changes), use a soil probe

Mapping Human Remains

Spatial distribution of evidence must be recorded, use a grid for sub-surface burials or concentrated surface deposits, map an object between two points of another object [triangulation (using angles) and trilateration (using distances)], baseline mapping is good for surface scatters because you can create your own datum

Recovering Human Remains

Assign tasks (recorder, mapper, photographer, excavators), establish a datum, establish a grid, begin with careful shovel-skimming, screen all soil, switch to trowels and other hand tools when the grave pit is clear, then expose, photograph, and map before removing the evidence

Forensic Taphonomy

the laws of burial and the study of the processes that affect organisms between death and discovery

Why is forensic taphonomy studied?

To estimate the postmortem interval (PMI), interpret postmortem events and/or treatment of remains, and distinguish between taphonomic alteration and perimortem trauma

What factors influence the decomposition of human remains?

Temperature, moisture/aridity, open-air vs. protected environments, soil chemistry, perimortem trauma, and scavenging

Autolysis

Cell destruction

Putrefaction

Bacteria in the digestive system proliferate, break down tissues

What is mummification and when can it occur?

A low-moisture environment resulting in the preservation of soft tissue

What is saponification and when can it occur?

When fat is converted into adipocere in areas with lower oxygen and lots of moisture

What is skeletonization?

The state where the majority of the soft tissues have decomposed

Diagenesis

Physical, chemical, or biological changes to bone after deposition

Entomological Processes

Rendezvous (flies appear, lay eggs), feast (eggs hatch and larvae feed), and exodus (at the end of 3rd instar, they leave the body and bury themselves in the soil)

Signs of Carnivore Scavenging

Pits, punctures, scoring, furrows

Signs of Bird Scavenging

Damage varies; often shallow scratches and targeting facial bones, but larger species can break ribs

Signs of Rodent Scavenging

Parallel striations

Sexual Dimorphism

Phenotypic differences between males and females of the same species

Morphology of the Pubic Bone

In the anterior view, females have a broader, wider pubic bone (rectangular rather than V-shaped) and a wider subpubic angle

Morphoscopic Methods of Estimating Biological Sex in the Os Pubis

Bottom of the ventral arc, sub-pubic concavity (sub-pubic angle), subpubic contour, medial aspect of the ischiopubic ramus, sciatic notch morphology, and preauricular sulcus

Morphoscopic Methods of Estimating Biological Sex in the Skull

Nuchal crest, mastoid process, supraorbital margin, supraorbital ridge/glabella, and the mental eminence

Osteometric Methods of Estimating Biological Sex

Long bone dimensions, using sectioning points (univariate) and discriminant functions (multivariate)

Morphoscopic Methods of Estimating Population Affinity in the Skull

Anterior nasal spine, inferior nasal aperture, interorbital breadth, nasal aperture width, nasal bone contour, and post-bregmatic depression

Formative Changes

Modifications that occur during growth and development, most commonly used for determining the age of subadults

Degenerative Changes

Modifications that occur as a result of age-related changes, wear and tear, and diseases

Methods for Estimating Age at Death with Formative Changes: Dental Development

The sequence of tooth formation, including the cusps, crown, root, and closing of the root apex, and the sequence of tooth eruption

Methods for Estimating Age at Death with Formative Changes: Diaphyseal Lengths

Measurement of immature long bones without epiphyses; age can be estimated until epiphyses unite

Methods for Estimating Age at Death with Formative Changes: Appearance and Fusion of Ossification Centers

Primary and secondary centers appear roughly according to a schedule (example: femur)

Methods for Estimating Age at Death with Formative Changes: Epiphyseal Union

The process by which primary and secondary ossification centers unite is normally correlated with chronological age. Most fusion occurs between 15-23 with the first being the elbow region and the last being the medial clavicle, which has a dimpled look before it is fused

Pubic Symphyseal Face in Younger Age Ranges

Prominent ridges and furrows, and the upper and lower extremities become delimited

Pubic Symphyseal Face in Middle Age Ranges

Lower rim complete dorsally; gap ventrally and the oval outline complete with remnants of billowing

Pubic Symphyseal Face in Older Age Ranges

The face becomes depressed and porous with ongoing depression, rim breakdown, and irregularity in shape

Features that Change on Sternal Rib Ends Over Time

Bone quality (dense & smooth to light & porous), pit shape (flat with billowing, then indentation, V-shaped, U-shaped), and rim edge (thick & rounded to thin & sharp)

Secondary Age Estimation Methods

Auricular surface, cranial suture closure, and dental wear

Biological Stature

Measured living stature, changes from the morning to the night

Reported Stature

Reported on legal documents or by family members, over- and under-estimates are common

Cadaveric Stature

Measured stature of deceased individual, soft tissues can loosen or tighten, used in research

Anatomical Stature Estimation Methods

Measure all bones that contribute to stature. Advantages are greater accuracy, not population/sex-specific, and control for anomalies. Disadvantage is you need a nearly complete skeleton

Fully Technique for Estimating Stature

First, measure the skull (basion-bregma), C2-S1 (max body height), femur, tibia, talus, and calcaneus, then sum for “skeletal height”

Regression Methods for Estimating Stature

First, take standard osteometric measurements, then, apply the population-specific regression formula, finally, report point estimate and prediction interval (95%)

Skeletal Anomolies

Deviations from typical skeletal anatomy (supernumerary bones or teeth, supernumerary vertebrae, accessory foramina or facets, septal aperture, sternal foramen, non-fusion anomalies, vertebral shifts, spondylolysis)

Skeletal Pathologies

Abnormal skeletal anomaly that results in functional or structural impairment (metastatic bone lesions, lytic lesions caused by brucellosis, porotic hyperostosis, cribra orbitalia, periosteal reactions)

Changes Related to Mechanical Stress

Osteoarthritis, osteoarthritis with eburnation, schmorl’s nodes, enthesophytes at achilles tendon insertion site

Compression

Squeezing force; object becomes shorter in the direction of the applied force

Tension

Stretching force; object becomes longer in the direction of the applied force

Bending

Compression on one side, tension on the other

Shear

Slides portions of an object relative to one another, parallel to the direction of force

Torsion

Combination of shear and twisting/rotation

Antemortem

Before death; requires evidence of an osteogenic reaction

Perimortem

Around the time of death; no osteogenic reaction, bone fractures as it would when fresh

Postmortem

After death; bone fractures as dried material (more brittle, small and more regular fragments, jagged appearance, recently broken edges are lighter in color)

Blunt Force Trauma

Relatively slow loading, relatively large area, the bone may permanently deform and preserve impressions of implements

Cranium: Radiating and Concentric Fractures

In blunt trauma, concentric features are created when bone collapses inward

Long Bones: “Butterfly” Fractures

The direction of the force goes towards the “body” of the butterfly

Sharp Force Trauma

Relatively slow loading, small surface area, beveled edge instrument. Bone is an excellent material for preserving SFT, and edged weapons can produce a mixture of blunt fractures and sharp-force injuries

Cut marks and stab wounds produced by knives

Narrow, v-shaped in cross-section, usually smooth, minimal wastage

Features of Saws

Tooth size and shape (teeth-per-inch), tooth set (alternate, wavy, raker), cutting action (push vs. pull as power stroke), and saw power (hand vs. mechanical)

Kerf

Groove created by a saw, wider, rectangular or w-shaped cross-section, visible striations, moderate wastage, “breakaway spurs”

High-Velocity Projectile Trauma

Rapid loading, small surface area, bone acts as a brittle material, shatters rather than deforms

Fracture Patterns

Plug and spall, radiating (propagating away from the impact site), concentric (curved or circular, surrounding the impact site)

Beveling

Bullet punches out the bone in a funnel-shape

Positive ID/Scientific ID

Linking unknown remains to an individual of known identity

Methods of Finding a Positive ID

DNA (nuclear, not mitochondrial), fingerprints, comparative radiography