Forensic anthropology

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Forensic anthropology is the application of the science of anthropology and its various subfields, including forensic archaeology and forensic taphonomy,[1] in a legal setting.

The most frequent use of forensic anthropology is in situations where the victim's remains are in the advanced stages of decomposition. A forensic anthropologist can assist in the identification of deceased individuals whose remains are decomposed, burned, mutilated or otherwise unrecognizable. Using physical markers present on an individual's skeleton, a forensic anthropologist can potentially determine a victim's age, sex, stature, and ancestry. In addition, to physical characteristics of the individual, forensic anthropologists can use skeletal abnormalities to potentially determine cause of death, past trauma such as broken bones or medical procedures, as well as diseases the individual suffered from such as bone cancer. Forensic anthropologists are also instrumental to the investigation and documentation of genocide and mass graves.

Along with forensic pathologists, forensic odontologists, and homicide investigators, forensic anthropologists are also expected to testify in court as expert witnesses.

History[edit]

Early history[edit]

Earnest Hooton, one of the pioneers in the field of physical anthropology.

The use of anthropology in the forensic investigation of remains grew out of the recognition of anthropology as a distinct scientific discipline and the growth of physical anthropology. The field of anthropology began in the United States and struggled to obtain recognition as a legitimate science during the early years of the twentieth century.[2] Earnest Hooton pioneered the field of physical anthropology and became the first physical anthropologist to hold a full-time teaching position in the United States.[3] In addition, Hooton was an organizing committee member of the American Association of Physical Anthropologists along with its founder Aleš Hrdlička. Hooton's students went on to create some of the first doctoral programs in physical anthropology during the early 20th century.[4] In addition to physical anthropology, Hooton was a proponent of criminal anthropology.[5] Now considered a pseudoscience, criminal anthropologists believe that certain criminal behaviors can be linked to specific physical characteristics. The use of criminal anthropology to try to explain certain criminal behaviors was a result of the eugenics movement popular during the time period. Interestingly, it is because of these ideas that skeletal differences were measured in earnest eventually leading to the development of anthropometry and the development of the Bertillon method of skeletal measurement by Alphonse Bertillon. The study of this information helped shape anthropologist's understand of the human skeleton and the multiple skeletal differences that can occur.

In addition to Earnest Hooton, another prominent early anthropologist included Thomas Wingate Todd. Todd was primarily responsible for the creation of the first, large, collection of skeletons in 1912. All together, Todd acquired 3,300 human skulls and skeletons, 600 anthropoid skulls and skeletons, and 3,000 mammalian skulls and skeletons.[6] Todd's contributions to the field of anthropology continue to be used to today and include various studies regarding suture closures on the skull and timing of teeth eruption in the mandible. In addition, Todd developed age estimates based on the physical characteristics of the pubic symphysis. These estimates, while updated to today's standards, are still used by forensic anthropologists to narrow down an age range of skeletonized remains.[7] These early pioneers legitimized the field of anthropology, but it was not until the 1940s with the help of Todd's student, Wilton M. Krogman, that forensic anthropology gained recognition as a legitimate subdiscipline.

The growth of forensic anthropology[edit]

During the 1940s, Krogman was the first anthropologist to actively publicize anthropologists' potential forensic value, going as far as placing advertisements in the FBI Law Enforcement Bulletin informing agencies of the ability of anthropologists to assist in the identification of skeletal remains. This period saw the first official use of anthropologists by federal agencies including the FBI and the U.S. Army Quartermaster Corps in the identification of war casualties during the Korean War.[5] It was at this time that forensic anthropology official began. The sudden influx of available skeletons for anthropologists to study, whose identities were eventually confirmed, allowed for the creation of more accurate formulas for the identification of sex, age,[8] and stature[9] based solely on skeletal characteristics. These formulas, developed in the 1940s, are still in use today.

The professionalization of the field began soon after, during the 1950s and 1960s. This move coincided with the replacement of coroners with medical examiners in many locations around the country.[5] It was during this time that the field of forensic anthropology gained recognition as a separate field within the American Academy of Forensic Sciences and the first forensic anthropology research facility and body farm was opened by William M. Bass.[10] It was at this time that forensic anthropologists working high profile cases began getting attention from the general population. One of the major cases of the era involved anthropologist Charles Merbs who helped identify the victim murdered by Ed Gein.[11]

Forensic anthropology today[edit]

Exhumed bodies of victims of the Srebrenica Genocide in a mass grave.

Today, forensic anthropology is a well established discipline within the forensic field. Anthropologists are called upon to investigate remains and to help identify individuals when other physical characteristics no longer exist. In addition to these duties, forensic anthropologists often assist in the investigation of war crimes and mass fatality investigations. Anthropologists have been tasked with helping to identify victims of the 9/11 terrorist attacks[12] as well as plane crashes such as the Arrow Air Flight 1285 disaster[13] and the USAir Flight 427 disaster.[14] Anthropologists have also helped identify victims of genocide in countries around the world. Specific war crimes anthropologists have helped investigate include the Rwandan Genocide[15] and the Srebrenica Genocide.[16] Organizations such as the Forensic Anthropology Society of Europe, the British Associate for Forensic Anthropology, and the American Society of Forensic Anthropologists continue to provide guidelines for the improvement of forensic anthropology and the development of standards within the discipline.

Application[edit]

One of the main tools in the identification of individuals used by forensic anthropologists is their knowledge of osteology and the various differences that occur within the human skeleton. During the course of 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 how the skeleton can differ between individuals.

Determination of sex[edit]

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 great level of accuracy.[17] The examination of the pubic arch and the location of the sacrum can help determine sex.

Female pelvis. Note wide pubic arch and shorter, pushed back sacrum
Male pelvis. Note narrow pubic arch and longer sacrum.

Unfortunately, the presence of the pelvis is not a guarantee, so forensic anthropologists must be aware of other areas on the skeleton that have distinct characteristics between sexes. The skull also contains multiple markers that can be used to determine the sex of an individual. Specific markers on the skull include the temporal line, the eye sockets, the supraorbital ridge,[18] as well as the nuchal lines, and the mastoid process.[19] In general, the male skull tends to be larger and thicker than female skulls. Also, male skulls tend to have more pronounced ridges.[20]

It is important for forensic anthropologists to take into account all available markers in the determination of sex. This is due to the scale of which skeletal differences between the sexes exists in. For example, It is possible that a female may have a slightly more narrow than normal pubic arch. It is for this reason that anthropologist usually classify sex as either one of five possibilities: male, may be male, indeterminate, may be female, or female.[21] In addition, forensic anthropologists are generally unable to make a sex determination unless the individual was an adult at the time of death. The sexual dimorphisms present in the skeleton begin to occur during puberty and are not fully pronounced until after sexual maturation.[22]

Determination of stature[edit]

The determination of stature by anthropologists is based off 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. Stature is given as a range of possible values, in centimeters, and typically computed by measuring the bones of the leg. The three bones that are used are the femur, the tibia, and the fibula.[23] In addition to the leg bones, the bones of the arm, the humerus, ulna, and radius can be used.[24] 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.[25] By knowing all the variables associated with height, a more accurate estimate can be made. For example, a male formula for stature estimation using the femur is 2.32 × femur length + 65.53 ± 3.94 cm. A female of the same ancestry would use the formula, 2.47 × femur length + 54.10 ± 3.72 cm.[26] It is also important to note an individual's approximate age when determining stature. This is due to the shrinkage of the skeleton that naturally occurs as a person ages. After age 30, a person loses approximately one centimeter of their height every decade.[23]

Determination of age[edit]

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.[27] When teeth are not available, children can be aged based on which growth plates are sealed. The tibia plate seals around age 16 or 17 in girls and around 18 or 19 in boys. The clavicle is the last bone to complete growth and the plate is sealed around age 25.[28] In addition, if a complete skeleton is available anthropologists can count the number of bones. While adults have 206 bones, the bones of a child have not yet fused resulting in a much higher number.

The aging of adult skeletons is not as straightforward as aging a child's skeleton as there is little continuing skeletal changes once adulthood is reached.[29] One possible way to estimate the age of an adult skeleton is to look at bone osteons under microscopic examination. New osteons are constantly formed by bone marrow even after the bones stop growing. Younger adults have fewer and larger osteons while older adults have smaller and more osteon fragments.[28] Another potential method for determining the age of an adult skeleton is to look for arthritis indicators on the bones. Arthritis will cause noticeable rounding of the bones.[30] A high degree of rounding from arthritis coupled with the size and number of osteons can help an anthropologist narrow down a potential age range for the individual.

Determination of ancestry[edit]

The determination of an individual's ancestry is typically grouped into three historical groups, caucasoid, mongoloid, and negroid. However, the use of these classifications is become much harder as the rate of interracial marriages increases and markers become less defined.[31] Typically, the maxilla is used to help anthropologists determine an individual's ancestry due to the three basic shapes, hyperbolic, parabolic, and rounded, belonging to the three historical ancestries, negroid, caucasoid, and mongoloid respectively.[32] In addition to the maxilla, the zygomatic arch and the nasal opening have been used to narrow down possible ancestry.[33] By measuring distances between landmarks on the skull as well as the size and shape of specific bones anthropologists can use a series of equations to estimate ancestry. In addition, a program called FORDISC has been created that will calculate the most likely ancestry using complex mathematical formulas.[34] This program is continually updated with new information from known individuals to maintain a database of current populations and their respective measurements.

Other markers[edit]

Anthropologist are also able to see other markers present on the bones. Past fractures experienced by the individual will be evident by the presence of bone remodeling. The examination of any fractures on the bones can potentially help determine cause of death as well by determining 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 while peri and post-mortem fractures will not. Peri-mortem fractures will usually appear clean while post-mortem breaks will appear to be falling apart.[35] Diseases, such as bone cancer, would be present in any bone marrow samples and can help narrow down the list of possible identifications.

Subfields[edit]

Forensic archaeology[edit]

Forensic archaeologists employ their knowledge of proper excavation techniques to ensure that remains are recovered in a controlled and forensically acceptable manner.[36] When a body, or in the case of mass graves bodies, are found partially or completely buried the proper excavation of the remains will ensure that any evidence present on the bones will remain intact. In addition to remains, archaeologists are trained to look for objects contained in and around the excavation area. These objects can include such anything from wedding rings to potentially probative evidence such as cigarette butts or shoeprints.[37]

In addition to excavating already known sites, forensic archaeologists can help determine potential grave sites that might have been overlooked. Differences in the soil can help forensic archaeologists locate these sites. During the burial of a body, a small mound of soil will form from the filling of the grave. The loose soil and increasing nutrients from the decomposing body encourages different kinds of plant growth than surrounding areas. Typically, grave sites will have looser, darker, more organic soil than areas around it.[38] The search for additional grave sites can be useful during the investigation of genocide or mass graves to search for additional burial locations.

Forensic taphonomy[edit]

The examination of remains can help build a peri and post-mortem profile of the individual.

The examination of skeletal remains often takes into account environmental factors that affect decomposition. Forensic taphonomy is the study of these postmortem changes to human remains caused by soil, water, and the interaction with plants, insects, and other animals.[39] In order to study these effects, body farms have been set up by multiple universities. Students and faculty study various environmental affects on the decomposition of donated cadavers. At these locations, cadavers are placed in various situations and their rate of decomposition along with any other factors related to the decomposition process are studied. Potential research projects can include whether black plastic causes decomposition to occur faster than clear plastic or the effects freezing can have on a dumped body.[40] Forensic taphonomy is divided into two separate sections, biotaphonomy and geotaphonomy.

Biotaphonomy is the examination of biological remains in order to ascertain how decomposition or destruction occurred.[41] Biotaphonomy is the study of how the environment affects the decomposition of the body. This can include factors such as animal scavenging, climate, as well as the size and age of the individual at the time of death. Biotaphonomy must also take into account mortuary services that are commonly conducted and their affects on decomposition such as embalming.[42]

Geotaphonomy is the examination of how the decomposition of the body affects the environment. Geotaphonomy examinations can include how the soil was disturbed, pH alteration of the surrounding area, and either the acceleration or deceleration of plant growth around the body.[41] By examining these characteristics, examiners can begin to piece together a timeline of the individual during and after their death. This can potentially help determine the time since death, whether or not trauma present on the skeleton was a result of peri or post-mortem activity, as well as if scattered remains were the result of scavengers or a deliberate attempt to conceal the remains by an assailant.[42]

Education[edit]

Forensic Anthropology Lab at the National Museum of National History, Smithsonian Institution, Washington D.C.

Individuals looking to become forensic anthropologists should obtain a bachelor's degree in anthropology from an accredited university. During their studies they should focus on physical anthropology as well as osteology. In addition it is recommended that individuals take courses in a wide range of sciences such as biology, chemistry, anatomy, and genetics.[43]

Once undergraduate education is completed the individual should proceed to graduate level courses. Typically, forensic anthropologists obtain doctorates in physical anthropology and have completed coursework in osteology, forensics, and archaeology. It is also recommended that individuals looking to pursue a forensic anthropology profession get experience in dissection usually through a gross anatomy class as well as useful internships with investigative agencies or practicing anthropologists.[1] Once the individual has completed their educational requirements they should strive to become certified by the forensic anthropology society in their region. This can include the IALM exam given by the Forensic Anthropology Society of Europe[44] or the certification exam given by the American Board of Forensic Anthropology.[45]

Typically, most forensic anthropologists perform forensic casework on a part-time basis however there are individuals who work in the field full-time usually with federal or international agencies. Forensic anthropologists are usually employed in academia either at a university or a research facility.[46]

Ethics[edit]

Like other forensic fields, forensic anthropologists are held to a high level of ethical standards due to their work in the legal system. Individuals who purposefully misrepresent themselves or any piece of evidence can be sanctioned, fined, or imprisoned by the appropriate authorities depending on the severity of the violation. Individuals who fail to disclose any conflict of interests or who fail to report all of their findings, regardless of what they may be, can face disciplinary actions.[47] It is important that forensic anthropologists remain impartial during the course of an investigation. Any perceived bias during an investigation could hamper efforts in court to bring the responsible parties to justice.[48]

In addition to the evidentiary guidelines forensic anthropologists should always keep in mind that the remains they are working with were once a person. If possible, local customs regarding dealing with the dead should be observed and all remains should be treated with respect and dignity.

Notable forensic anthropologists[edit]

Cultural references[edit]

Temperance "Bones" Brennan is a fictional forensic anthropologist in the television series Bones.

See also[edit]

References[edit]

  1. ^ a b Nawrocki, Stephen P. (June 27, 2006). "An Outline Of Forensic Anthropology" (PDF). Retrieved August 21, 2015. 
  2. ^ Stewart, T.D. (1979). "In the Uses of Anthropology". Forensic Anthropology (American Anthropological Association). Special Publication (11): 169–183. 
  3. ^ Shapiro, H.L. (1954). "Earnest Albert Hooton 1887-1954". American Anthropologist 56: 1081–1084. 
  4. ^ Spencer, Frank (1981). "The Rise of Academic Physical Anthropology in the United States (1880-1980)". American Journal of Physical Anthropology 56: 353–364. 
  5. ^ a b c Snow, Clyde Collins (1982). "Forensic Anthropology". Annual Review of Anthropology 11: 97–131. 
  6. ^ Cobb, W. Montague (1959). "Thomas Wingate Todd, M.B., Ch.B., F.R.C.S. (Eng.), 1885-1938". Journal of the National Medical Association 51 (3): 233–246. 
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  8. ^ McKern, T.W.; Stewart, T.D. (1957), Skeletal Age Changes in Young American Males (Technical Report EP-45), Headquarters, Quartermaster Research and Developmental Command 
  9. ^ Trotter, M.; Gleser, G.C. (1952). "Estimation of Stature from Long Bones of American Whites and Negroes". American Journal of Physical Anthropology 10: 463–514. 
  10. ^ Buikstra, Jane E.; King, Jason L.; Nystrom, Kenneth (2003). "Forensic Anthropology and Bioarchaeology in the American Anthropologist: Rare but Exquisite Gems". American Anthropologist 105 (1): 38–52. 
  11. ^ Golda, Stephanie (2010). "A Look at the History of Forensic Anthropology: Tracing My Academic Genealogy". Journal of Contemporary Anthropology 1 (1). 
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  15. ^ Nuwer, Rachel (November 18, 2013). "Reading Bones to Identify Genocide Victims". The New York Times. Retrieved August 18, 2015. 
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  28. ^ a b "Young or Old?". Smithsonian National Museum of Natural History. Retrieved August 20, 2015. 
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  34. ^ "Ancestry, Race, and Forensic Anthropology". Observation Deck. March 31, 2014. Retrieved August 20, 2015. 
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  39. ^ Pokines, James; Symes, Steven A. Manual of Forensic Taphonomy. CRC Press. ISBN 9781439878415. 
  40. ^ Killgrove, Kristina (June 10, 2015). "These 6 'Body Farms' Help Forensic Anthropologists Learn To Solve Crimes". forbes.com. Retrieved August 20, 2015. 
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  42. ^ a b Nawrocki, Stephen P. (June 27, 2006). "An Outline Of Forensic Taphonomy" (PDF). Retrieved August 20, 2015. 
  43. ^ Hall, Shane. "Education Required for Forensic Anthropology". Retrieved August 21, 2015. 
  44. ^ "FASE/IALM Certification". Forensic Anthropology Society of Europe. Retrieved August 21, 2015. 
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  48. ^ "Code of Ethics and Conduct" (PDF). American Board of Forensic Anthropology. 2012. Retrieved August 21, 2015. 

External links[edit]