Forensic Anthropology Lab: Sex, Age, Ancestry & Stature Estimation

Forensic taphonomy examines changes from death to discovery, studying decomposition stages and environmental factors. The term derives from Greek 'tapho' (burials) and 'nomos' (law). It has two branches: biotaphonomy (examining how decomposition affects the body) and geotaphonomy (examining how bodies affect their environment). Decomposition progresses through five stages: Fresh (death to bloating, green discoloration, insect activity begins), Bloating (anaerobic bacteria digest tissue, gas production, body temperature rises up to 50°C), Active Decay (skin breakdown, gas release), Advanced Decay (reduction to skin, cartilage, bone), and Skeletal (complete skeletonization). Six main sources cause post-mortem changes: disfiguration, animal scavenging, fire, weather, burial, and water. Fire causes bone discoloration, shrinking, cracking, and warping. Weather effects include sand blasting from wind, rehydration from rain, and sun-induced shrinking, cracking, and flaking. Burial causes cracking without impact points and cortical bone erosion. Water transport involves three phases: fluvial movement by currents, bloating causing surface rise, and separation of body parts. Rounder bones travel farther than flatter bones. Body Farms (Anthropological Research Facilities) are land areas where donated bodies study decomposition under various conditions. Dr. William Bass founded the first at University of Tennessee in 1981 after consulting on a Civil War grave where a body appeared fresh despite 100+ years burial in a sealed casket. The facility has received over 1,800 bodies by 2018. Global expansion includes West Carolina (2007), Texas State (2008, 26 acres), Australia (2016), Amsterdam (2017), and Canada (2021). These facilities help estimate PMI in various situations and provide law enforcement training.

Forensic taphonomy is an interdisciplinary branch of forensic science that studies postmortem changes in the human body, combining biology, geology, entomology, and environmental science to estimate time since death (PMI), identify environmental conditions, detect body movement, and locate hidden graves; the decomposition process occurs through distinct stages—fresh, bloat, active decay, advanced decay, and skeletal/dry stage—and is influenced by factors such as temperature, humidity, soil type, insect activity, and human interventions like burial or chemical treatment.

Environmental factors such as temperature, moisture, exposure, and location significantly influence the post mortem interval (PMI) estimation; higher temperatures accelerate decomposition (e.g., Arizona desert bodies skeletonize in 3 months vs. Tennessee in 1 year vs. Canada taking 8 years), while moist environments slow decomposition and promote mummification, and body exposure affects insect colonization patterns and scavenger activity.

Taphonomy is the study of decomposition of biological organisms by studying processes that affect decomposition, derived from Latin 'tapos' and 'Nomos'. In forensics, it studies decomposition history since body deposition, with applications including PMI estimation, body identification, and determining cause and manner of death. Taphonomy is interdisciplinary, drawing from anthropology, archeology, botany, entomology, Geoscience, meteorology, microbiology, molecular biology, ornithology, pathology, and palaeontology. Two primary types exist: biota fauna me (environmental, biological, and cultural/behavioral factors including trauma and embalming) and geo taphonomy (environmental factors affecting burial including soil pH, drainage, and erosion). The ecology of decomposition centers on arthropods—insects, spiders, scorpions, mites, centipedes, and crustaceans—which are central to decomposition. Four categories exist: necrophagous species (flies, beetles feeding on corpse tissue), omnivores (ants, wasps, some beetles), parasites/predators (species parasitizing maggots), and incidentals (spiders, mites, centipedes). The Coleoptera (beetles) and Diptera (flies) orders are the most prominent insect groups. Arthropods are key in PMI estimation due to their predictive breeding and development behaviors.

Post-mortem taphonomic changes are alterations to remains after death caused by environmental factors. In this case, taphonomic changes included evidence of carnivore scavenging (pits, punctures, and scoring) and rodent scavenging (parallel scoring damage). Post-mortem staining of the cortical and trabecular bone ranged in color from dark yellowish brown to reddish brown, consistent with the tannic soils of the Mayakachi wetlands. Isolated patches of black and red discoloration consistent with fungi or mold were observed in the bones of the lower extremity. White coloration from adipocere was also observed, consistent with decomposition in a wet environment.

Forensic odontology uses dental records for human identification. Three matching rules are required: three matching fillings, three specific points for conclusion, and three missing teeth in the same quadrant with three erupted third molars. The Gustafson method estimates age using six dental characteristics: attrition (wear patterns indicating age and diet), periodontosis (gum recession), secondary dentine deposition (calcium accumulation), cementum apposition, root resorption, and root transparency. These features help identify individuals and estimate age in forensic investigations.

Forensic odontology uses dental analysis to identify unknown individuals. Experts compare dental development stages with reference charts to estimate age within 3-6 months. Dental wear patterns reveal occupation (construction workers show characteristic wear from ingesting cement particles). Analysis determines sex from canine characteristics, biological groups from dental morphology, and demographic information from dental care quality. This science originated in 1897 after the Bazar de la Charité fire, where the Duchess of Alençon was identified by her dentist.

Forensic odontologists (치과 법의관) use dental records to identify deceased individuals. Each person's dental work, including fillings, crowns, and implants, creates a unique pattern that can be matched against dental records. They also estimate age through tooth development and wear patterns. Forensic odontologists work with other forensic professionals to reconstruct events and identify victims in mass casualty situations. The profession requires specialized training and carries significant responsibility in helping families find closure.

Dental age estimation provides age ranges rather than exact ages, with main categories: 0-18 years (non-adults), 20-35 years (subadults), adults, and elderly. Age estimation is more accurate in non-adults due to active dental development. The best method is dental mineralization, followed by eruption patterns. Key developmental milestones include: first permanent molar at 6 years, mixed dentition beginning at 6 years, completion of deciduous dentition by 12.5 years, and third molar eruption between 16-23 years. Non-adults are easier to estimate due to active development, while adults require analysis of degenerative changes. Forensic odontology applies to criminal law when dental-related vestiges exist (bite marks, dental injuries). According to Article 158 of the CPP, when crimes leave vestiges, forensic examination is indispensable. Applications include: bite mark analysis for victim identification, cadaver identification (especially in carbonized remains where teeth are most resistant), skeletal analysis, facial reconstruction, and injury documentation. The Tan case (2007) and Brumadinho disaster demonstrate its importance in mass disaster victim identification. Dentists must report mandatory notifications (suspected abuse, infectious diseases, work accidents) to authorities.

Forensic odontology applies oral knowledge for civil and criminal matters. Applications include age estimation (80-70% of field), human identification (dental traits, bitemark analysis, rugoscopy, DNA), and facial reconstruction. Teeth withstand trauma, water, heat, and are excellent DNA sources. Challenges include lack of centralized dental records in India and risk of wrong identification. A good BDS is sufficient for entry; training progresses from cast age estimation to X-rays, enamel, and ground sections.

Forensic anthropologists use software programs like FORDISK to analyze skeletal measurements. Data from multiple skeletons is entered into the program, which graphs and compares measurements against established databases. This computer-aided analysis helps determine ancestry and other characteristics by comparing unknown skeletons to reference populations.

The researcher used a new technology called FORDISC to estimate the sex and ancestry of the remains. This technology allows researchers to analyze bone measurements with realistic assumptions about who could have been on Nikumaroro island during the relevant time period.

Forensic identification databases like FORDISC use cranial measurements to estimate ancestry or racial classification of unknown individuals by comparing them to known populations. However, these databases contain fundamental problems: they rely on the same measurement criteria that were originally used to create racial categories in the 1800s, which were inherently biased and scientifically flawed. When populations not represented in the database are analyzed, the system defaults to the closest available category regardless of accuracy. This creates persistent misidentifications and reinforces problematic racial classifications in forensic practice, even when DNA evidence might tell a different story.

This section covers skeletal sex, ancestry, and stature estimation. Male traits observed on the cranium included large mastoid processes, blunt supraorbital margin, pronounced globular well-developed nuchal region with inion hook, and robust mental eminence. The ossa coccyx presented with narrow sub-pubic angle, greater sciatic notch, tall and narrow helix, absent ventral arc, and narrow pelvic inlet. Statistical analysis estimated the skeletal remains were male. For ancestry, the cranium presented with a long nasal spine, patent nasal sill, narrow nasal aperture, angled nasals, S-shaped maxillary sutures, Carabelli's cusp, anterior bulging transverse palatine sutures, and simple vault sutures. Statistical analysis estimated the decedent was white. For stature, measurements of the radius (264 millimeters) and ulna (277 millimeters) were used with the Forensic Discriminant Function 3.1, calculating forensic stature for white male ancestry groups as 66.2 to 74.9 inches (approximately 5 feet 6 inches to 6 feet 2 inches).

Unknown corpses arrive at morgues without identification, representing approximately 3% of cases in Milan (30 annually). Forensic anthropology creates biological profiles including sex, age, stature, and ancestry to aid identification. Cranial measurements and software like FORDISC help classify ancestry, though these tools can produce errors when applied to different populations. The American software was trained on European Americans and African Americans, not global populations. Ethnic categories are not static but evolve over time—American 'White' and 'Black' categories developed through specific historical processes over just four centuries. This demonstrates that ethnic classifications are fluid and culturally constructed rather than biologically fixed.

Forensic anthropology applies physical anthropology to legal cases involving the body. Unlike paleopathology (studying ancient peoples without legal consequences), forensic anthropology deals with cases where someone could face criminal charges. Key legal requirements include chain of custody—documented records of every person handling evidence—and contamination prevention through secured crime scenes. The primary objectives are determining victim identity and establishing what happened to the victim, distinguishing between homicide, suicide, accident, or natural causes.

A forensic anthropologist is a physical anthropologist who applies specialized knowledge to solve criminal cases and assist in medical-legal identification processes; their work involves examining skeletal remains to determine sex, age, stature, and number of individuals, as well as identifying living persons through anthropometry, somatoscopy, fingerprints, DNA, and other biological markers, making them essential experts in criminal investigations and courtroom testimony.

The purpose of an anthropologist report should be stated clearly. The case report should record physical observations on the remains, identify important biological characteristics, identify and differentiate changes due to natural and cultural forces, and provide information in a meaningful and understandable form to the medical legal officer. As part of preliminary understanding, a report should be agreed upon. The report is generated by the anthropologist after careful examination, research, and reflection. The complexity of the case determines how long this process takes. The report should provide the most detailed and precise data that can be provided at the time, however it cannot be modified if a statement is unclear or if the clue leading to a particular conclusion does not make sense to the investigator. It is reasonable to ask for further clarification. If additional technical tests are conducted, information should be given to the anthropologist for consideration. Any new evidence may require a new look at anthropologist findings. Questions concerning reports need to be returned in writing, not verbally. It is always a bad idea to press the anthropologist for detailed and positive determination during the recovery phase or initial parts of the examination phase, as speculation is dangerous. Although everyone wants results as soon as possible, rushing costs time, efforts, and credibility. The report should provide a succinct determination of results which can be sustained by defense. Each major biological characteristic should be identified, and the anthropologist should state the conclusion as clearly and unambiguously as possible. The report should include a discussion of how each result has been reached, however a full discussion of techniques and reasoning behind the use of techniques over another is not required. The most useful reports are complete yet concise. The report should avoid conclusions that cannot be sustained within the anthropologist's sphere of knowledge. Anthropologists do not know everything, and their comments should be limited to their expertise. Investigators may damage their case anytime they ask for expert statements from people willing to speak on subjects beyond their field.

Forensic anthropology applies anthropological methods to legal matters, focusing on human skeletons within the broader discipline of physical/biological anthropology. This field serves diverse roles including law enforcement consultation, academia, medical examiner offices, disaster response, and expert witness testimony. Core responsibilities involve determining the 'who, what, when, and where' of death scenes, though the 'why' of death requires medical examination. The systematic methodology includes differentiating human from non-human remains through osteological knowledge, classifying remains as contemporary (under 50 years) or non-contemporary, examining taphonomic changes (environmental effects on remains), contextual indicators, and biocultural factors. Field practices encompass protecting scene integrity, mapping with compass azimuth techniques, systematic excavation and recovery, maintaining chain of custody, calculating minimum number of individuals (MNI), conducting biological profiling (sex, age, geographic/cultural affiliation, stature, unique characteristics), and trauma analysis categorizing injuries as antemortem, perimortem, or postmortem. This comprehensive framework transforms skeletal remains into actionable evidence for criminal investigations and humanitarian efforts.

Workshop 1 requires developing three components: (1) Chain of custody flowchart using platform manual as reference but creating original diagram; (2) Cranial measurements on four skull projections (anterior, lateral, superior, inferior) using 'compendio de métodos antropológicos forenses'; (3) Timeline diagram summarizing forensic anthropology history. Groups of three maintain same groups for final project.