One of the main tools forensic anthropologists use in the identification of remains is their knowledge of
osteology and the differences that occur within the human skeleton. During an investigation, anthropologists are often tasked with helping to determinate an individual's sex, stature, age, and ancestry. To do this, anthropologists must be aware of how the human skeleton can differ between individuals.
Determination of sex Depending on which bones are present, sex can be determined by looking for distinctive
sexual dimorphisms. When available, the
pelvis is extremely useful in the determination of sex and when properly examined can achieve sex determination with a great level of accuracy. On average, male teeth are slightly larger than female teeth, with the greatest difference observed in the canine teeth. Examination of internal dental tissues has also shown that male teeth consist of absolutely and proportionately greater quantities of dentine than females. Such differences in dental tissue proportions could also be useful in sex determination.
Determination of stature The
estimation of stature by anthropologists is based on a series of formulas that have been developed over time by the examination of multiple different skeletons from a multitude of different regions and backgrounds. There are two major approaches for estimating stature, the mathenatical method and the anatomical method. The mathematical method uses the mesurements of skeletal element and regression equations or maximum likelihood equaitons.Stature is given as a range of possible values, in centimeters, and typically computed by measuring the bones of the leg, since they are the ones that best correlate with the total height of an individual. The three bones that are used are the
femur, the
tibia, and the
fibula. The formulas that are used to determine stature rely on various information regarding the individual. Sex, ancestry, and age should be determined before attempting to ascertain height, if possible. This is due to the differences that occur between populations, sexes, and age groups.
Determination of age The determination of an individual's age by anthropologists depends on whether or not the individual was an adult or a child. The determination of the age of children, under the age of 21, is usually performed by examining the teeth. Younger adults have fewer and larger osteons while older adults have smaller and more osteon fragments. There are also several factors that can alter the state of a bone and its preservation. These include taphonomy and postmortem events. Age estimation relies on the skeletal elements available for analysis, and some bones are more resiliant than others, resulting in different levels of preservation. Experimental trials show that the bone more frequently surviving taphonomic conditions is both the auricular surface and acetabulum when compared to other skeletal areas. The lowest yielding method to survive harsh conditions is the iscan method with examines the fourth rib of a individual.
Age estimation of living individuals Age estimation of living individuals is carried out by estimating the biological age when the chronological age of the individual is unknown or uncertain because of the lack of valid identity documents. It is used to confirm if an individual has reached a specific age threshold in cases of criminal liability, asylum seekers and unaccompanied children, human trafficking, adoption, and competitive sports. Guidelines by the Study Group on Forensic Age Diagnostics (Arbeitsgemeinschaft für Forensische Altersdiagnostik, AGFAD), propose that a three-step procedure should be followed for the age estimation: the first step is a physical examination; the second step include the assessment of the hand/wrist development using plain radiographs; the third step is a dental assessment. One of the most used methodologies for the estimation of age from the development of the hand and wrist is the Greulich and Pyle Atlas, whilst to assess dental development the most common method used so far is the 8-teeth technique developed by Demirjian
et al.. Where the estimated age of the individual might be above 18 years of age, it is possible to use the development of the medial end of the
clavicle. Traditionally, those undertaking age estimation in the living, adopt imaging techniques such as plain radiographies and CT scans to carry out the age estimation, however, lately, due to ethical issues surrounding the use of ionising medical imaging modalities for non-medical purposes (e.g., forensic purposes),
magnetic resonance imaging, a radiation free medical imaging modality, is being investigated to develop new methodologies to estimate the age of living individuals. The pubis symphysis displays consistent observale degenerative changes throughout the cours of life, making it a reliable marker for age estimaiton. Using 3D reconstruction of computes tomography (CT) scans, you can examin the pubis symphysis to estimate the age of a living individual. The Suchey-Brooks method, wich looks at morphological changes in the pubic symphysis, was show through experimental trials that it captures the true age of the patient 79.5 persent of the time. Each misclassification was due to underestimations of age, and it was more common to capture the true age of females then males.
Determination of ancestry The estimation of individuals' ancestry is typically grouped into three groups. However, the use of these classifications is becoming much harder as the rate of interancestrial marriages increases. Research presented at the 2012 Annual Meeting of the
American Association of Physical Anthropologists concluded that ForDisc ancestry determination was not always consistent, and that the program should be used with caution.
Other markers Anthropologists are also able to see other markers present on the bones. Past fractures will be evident by the presence of
bone remodeling but only for a certain amount of time. After around seven years, bone remodelling should make the presence of a fracture impossible to see. The examination of any fractures on the bones can potentially help determine the type of trauma they may have experienced. Cause of death is not determined by the forensic anthropologist, as they are not qualified to do so. However, they are able to determine the type of trauma experienced such as gun shot wound, blunt force, sharp force, or a mixture thereof. It is also possible to determine if a fracture occurred ante-mortem (before death), peri-mortem (at the time of death), or post-mortem (after death). Ante-mortem fractures will show signs of healing (depending on how long before death the fracture occurred) while peri- and post-mortem fractures will not. Peri-mortem fractures can incorporate quite a large range of time, as ante-mortem trauma that is unrelated directly to death may not have had time to begin the healing process. Peri-mortem fractures will usually appear clean with rounded margins and equal discolouration after death, while post-mortem breaks will appear brittle. Post-mortem breaks will often be a different colour to the surrounding bone i.e. whiter as they have been exposed to taphonomic processes for a different amount of time. However, depending on how long there is between a post-mortem break and removal this may not be obvious i.e. through re-interment by a killer. Diseases such as bone cancer might be present in
bone marrow samples and can help narrow down the list of possible identifications. ==Subfields==