Craniofacial anthropometry

:"This article deals with races defined craniofacially (based on skull measurements) and not by typology (physical type) or genetic distance. Races categorized using alternative methods yield different groups, making them non-concordant."John Relethford, The Human Species: An introduction to Biological Anthropology, 5th ed. (New York: McGraw-Hill, 2003).]

Craniofacial anthropometry is a technique used in physical anthropology comprising precise and systematic measurement of the bones of the human skull. Among its more important applications are: forensics, facial reconstruction, and paleoanthropology. The field of phylogeography, on the other hand, once relied heavily on this technique but no longer does so. [The current standard reference is John C. Kolar and Elizabeth M. Salter, "Craniofacial Anthropometry: Practical Measurement of the Head and Face for Clinical, Surgical, and Research Use" (Springfield IL: C.C. Thomas, 1997).] Craniofacial anthropometry is a sub-field of Craniometry, which can be seen for more detail and history.

History

The historical development of craniofacial anthropometry started when anthropologists first measured human skulls as a way to categorize race. The beginning physical anthropologists used a holistic method where they examined multiple observable physical characteristics to determine race. This holistic approach was not "craniofacial anthropometry" but a typological method. As anthropologists gained access to methods of skull measure, they developed racial classification based on skull shape. The observable craniofacial skeletal differences ranged from breadth of nasal aperture, nasal root height, head shape e.g. mesocephalic, brachycephalic and doliocephalic, sagittal crest appearance, jaw thickness, browridge size, forehead slope, etc., but did not involve soft tissue differences such as nasal shape, eye color, skin color, lip shape, and hair type. Using a strictly skull based categorization method, these anthropologists organized three to four racial groups. Caucasoids were characterized by a doliocephalic shape, with receded zygomas, large browridge and a narrow nasal aperture. Secondly, Negroids were characterized by a mesocephalic head shape, with receded zygomas and wide nasal aperture. Third, Mongoloids were characterized as a brachycephalic head shape, absent browridges, small nasal aperture, and projecting zygomas. Additionally, Australoids whose craniofacial type fell between Negroids and Caucasoids was added. With the addition of this category, Thomas Huxley considered India to fall in this group's craniofacial measurements. [ [http://aleph0.clarku.edu/huxley/SM3/GeoDis.html Huxley, Thomas. On the Geographical Distribution of the Chief Modifications of Mankind.] 1870. August 14, 2006.]

In forensic anthropology

The adjective "forensic" refers to the application of this subfield of science to a court of law. Forensic anthropologists study the human skeleton in a legal setting. A forensic anthropologist can assist in the identification of a decedent through various skeletal analyses that produce a "biological profile". One part to a biological profile is a person's racial/ancestral affinity.

Caucasians generally have no prognathism; a notable size prominence of the cranium and forehead region; a narrow, tear-shaped nasal cavity; a "silled" nasal aperture; tower-shaped nasal bones; a triangular-shaped palate; and an angular and sloping eye orbit shape. Blacks typically have a broad and round nasal cavity; no dam or nasal sill; Quonset hut-shaped nasal bones; notable facial projection in the jaw and mouth area (prognathism); a rectangular-shaped palate; and a square or rectangular eye orbit shape. Asians are often characterized by relatively no prognathism; no nasal sill or dam; an oval-shaped nasal cavity; tent-shaped nasal bones; a horseshoe-shaped palate; and a rounded and non-sloping eye orbit shape. [ [http://www.redwoods.edu/Instruct/AGarwin/anth_6_ancestry.htm Forensic Anthropology - Ancestry] ]

It is important to note that many of these characteristics only have a higher frequency among particular races and the presence or absence of one or more does not automatically classify an individual into a racial group.Forensic Anthropologists utilize the Fordisc program to help in the interpretation of craniofacial measurements in regards to ancestry/race determination.

In medicine

Surgeons employ the methods of craniofacial anthropometry in order to reconstruct a patient's face, when necessary, to fit within the limits of what society expects Fact|date=June 2007.

In paleoanthropology

Paleoanthropologists use craniofacial anthropometry in the study of fossilized hominid bones in order to identify the species. Specimens of "Homo erectus" and athletic specimens of "Homo sapiens", for example, are virtually identical from the neck down but their skulls can easily be told apart.

In phylogeography

Phylogeography (see main article) is the science of identifying and tracking major long-distance migrations that bands of humans undertook, especially in prehistoric times. For a detailed account of Human migrations see that article. Linguistics can follow the movement of languages and archaeology can follow the movement of artifact styles, but neither can tell whether a culture's spread was due to a source population's physically migrating or to a destination population's simply copying the technology and learning the language. Craniofacial anthropometry helped resolve this because a people's physiognomy does not change rapidly due to mere migration.

Carleton S. Coon, a 20th century craniofacial anthropometrist, used the technique for his "The Origin of Races" (New York: Knopf, 1962). Because of the inconsistencies in the old three-part system (Caucasoid, Mongoloid, Negroid), Coon adopted a five-part scheme. He discarded the term "Negroid" as useless or misleading since it implied a dark skin-tone, which is found at low latitudes around the globe and is a product of adaptation. As shown in the map, he defined "Caucasoid" as a pattern of skull measurements and other phenotypical characteristics typical of populations in Europe, Central Asia, South Asia, West Asia, North Africa, and Northeast Africa (Ethiopia, and Somalia). He defined skulls typical of sub-Saharan Africa as "Congoid" and those of Southern Africa as "Capoid." Finally, he split "Australoid" from "Mongoloid" along a line roughly similar to the modern distinction between sinodonts in the north and sundadonts in the south. He argued that these races had developed independently of each other over the past half-million years, developing into Homo Sapiens at different periods of time, resulting in different levels of civilization. This raised considerable controversy and led the American Anthropological Association to reject his approach (although without mentioning him by name). [Marks, Jonathan "What it means to be 98% Chimpanzee" University of California Press, 2002, ISBN 9780520240643 pp. 76-77 [http://books.google.co.uk/books?id=HUBe0wjowLMC&pg=PA76&dq=coon+%22origin+of+races%22&ei=GqDKSLzvDZX4iQGF4KX3Cw&client=firefox-a&sig=ACfU3U1EeYDoitthqhZ9pvsJmzVAqFLQMA#PPA76,M1] ]

In a much earlier work, "The Races of Europe", Coon classified Caucasoids into racial sub-groups named after regions or archaeological sites such as Brünn, Borreby, Alpine, Ladogan, East Baltic, Neo-Danubian, Lappish, Mediterranean, Atlanto-Mediterranean, Irano-Afghan, Nordic, Hallstatt, Keltic, Tronder, Dinaric, Noric and Armenoid. This typological view of race, however, was, at the time of publication in 1939, starting to be seen as out-of-date among a few anthropologists.

With the discovery that many blood proteins vary consistently among populations, followed by the discovery of the DNA code, the invention of the polymerase chain reaction that amplifies trace amounts of DNA, and the decoding of the human genome, phylogeographers largely switched away from craniofacial anthropometry whenever DNA is available. This is because DNA findings are more replicable.Fact|date=June 2008

Challenges

Although the categorization of a skull is clearly given arbitrary parameters, it will not locate the owners geographic ancestry concretely all the time. While one's perception of an individual's race can be affected by cultural aspects, the "race" of his skull is less ambiguous. As Dr. Stan Rhine put it, "...it is clear that race does mean different things to different people. In the context of forensic anthropology, the term race is unambiguous." [ [http://library.med.utah.edu/kw/osteo/forensics/race.html Forensic Anthropology. Human Biological Variation] ] Although their craniofacial race based on skull indices is unambiguous, it will not pin point their geographic origins accurately all the time due to variation in skulls within a geographic region.

While this method produces useful results for the population of the United States, it is likely that it would not be reliable for populations from other countries [ [http://www.pbs.org/race/000_About/002_04-experts-01-09.htm The Online Companion to California Newsreel's 3 part documentary about race and society, science and history, "Race — The Power of an Illusion", Ask the Experts section] ] or historical periods. ["The assignment of skeletal racial origin is based principally upon stereotypical features found most frequently in the most geographically distant populations. While this is useful in some contexts (for example, sorting skeletal material of largely West African ancestry from skeletal material of largely Western European ancestry), it fails to identify populations that originate elsewhere and misrepresents fundamental patterns of human biological diversity", [http://monarch.gsu.edu/WebRoot$/fwilliams/CurrAnth%202005%20Williams%20et%202.pdf Forensic Misclassification of Ancient Nubian Crania: Implications for Assumptions about Human Variation, Frank L’Engle Williams, Robert L. Belcher, and George J . Armelagos] (pdf)] This is because the United States has traditionally had groups whose ancestries came from geographically distant locations, and which have generally remained endogamous in this country, for social reasons. As more immigrants from in between regions and as Americans become more racially mixed, such craniofacial identification is problematic.

Classification by craniofacial anthropometry does not necessarily coincide with genetic ancestry or social self-identification. For example, about one-third of so-called "White" Americans have detectable African DNA markers. [Heather E. Collins-Schramm and others, "Markers that Discriminate Between European and African Ancestry Show Limited Variation Within Africa," "Human Genetics" 111 (2002): 566-9; Mark D. Shriver and others, "Skin Pigmentation, Biogeographical Ancestry, and Admixture Mapping," "Human Genetics" 112 (2003): 387-99.] And about five percent of so-called "Black" Americans have no detectable "Negroid" traits at all, neither craniofacial nor in their DNA. [E.J. Parra and others, "Ancestral Proportions and Admixture Dynamics in Geographically Defined African Americans Living in South Carolina," "American Journal of Physical Anthropology" 114 (2001): 18-29, Figure 1.] In short, given three Americans, one who self-identifies and is socially accepted as U.S. White, another one who self-identifies and is socially accepted as U.S. Black, and one who self-identifies and is socially accepted as U.S. Hispanic, and given that they have precisely the same Afro-European mix of ancestries (one "mulatto" grandparent), there is quite literally no objective test that will identify their U.S. endogamous group membership without an interview. [Carol Channing, "Just Lucky I Guess: A Memoir of Sorts" (New York: Simon & Schuster, 2002); Gregory Howard Williams, "Life on the Color Line: The True Story of a White Boy who Discovered he was Black" (New York: Dutton, 1995)] In practice, the application of such forensic criteria ultimately comes down to whether the skull "looks Negroid," "Caucasoid," or "Mongoloid" in the eye of each U.S. forensic practitioner.

Footnotes

ee also

* Race (historical definitions)
* Craniometry
* Eigenface