AN321 - FORENSIC OSTEOLOGY
W. B. WOOD
The University of Queensland
Australia is a multiracial society. In recent years, migrations of peoples from Southeast Asia and the Pacific Islands have added considerably to the earlier blend of Caucasian and Australian Aborigine that had inhabited the country since European settlement in 1788. In addition, the presence of small but significant numbers of Chinese, Indian, Melanesian, and other minority groups has converted Australia into a genetic mixing bowl. The possibility is ever increasing therefore that skeletal remains of forensic interest may be derived from any one of a large variety of ethnic groups and admixtures.
Unfortunately the lack of study and knowledge of the effects of varying degrees of genetic admixture on the phenotypic expression of skeletal traits is making racial or ethnic allocation of unknown skeletal remains increasingly hazardous. Even the gross allocation of an unknown skeleton to one of the 5 major racial types - Caucasian, Mongoloid, Negroid, Australoid or Polynesian is occasionally no longer possible with any certainty.
The determination of racial or ethnic affinity of skeletal remains is based upon:
a) features or characteristics of the bones that are genetically inherited and found especially in
the cranium and mandible.
b) features of the bones that are the result of the cultural beliefs, habits and environs of
the people concerned. These influences may directly or indirectly affect the
appearances, dispositions and associations of the skeletal remains and therefore assist
with racial determination.
c) associated grave goods or other cultural material.
Racial characteristics of the skeleton have been extensively studied and documented only for those population groups for which large reference skeletal collections have been available. Such studies have been possible due to the deliberate collection of modern material (eg from anatomy departments or postmortem rooms, skeletons recovered during cemetery relocation or postwar military repatriation schemes), or from the excavation of ancient burial grounds e.g. European, Amerindian, Polynesian, Australian Aboriginal etc.
Little research has been done on the skeletal characteristics of many of the Asian ethnic groups now settling in Australia nor on the effects of racial admixture on skeletal trait (phenotypic) expression. The recent worldwide policies of various indigenous groups to reclaim the skeletons of their ancestors from museums and other institutions for reburial, is lessening the chances for continuing research and improvement in this important area of skeletal investigation.
RACIAL DETERMINATION FROM THE CRANIUM AND MANDIBLE
Information on the racial affinities of a skeleton is best ascertained from the cranium and mandible. Experts can usually sort the crania and mandibles of the 5 major racial groups of the world with 85-90% accuracy, using only subjective criteria. Sorting into more limited regional varieties or ethnic groups is much more difficult and usually beyond the scope of the average forensic anthropologist.
Objective statistical methods based on selected cranial measurements are available for some racial groups (Giles & Elliot 1962; Howells 1970) with claimed accuracy of 80-90%. These methods do have some problems however as pointed out by Birkby (1966). The most recent publications on metrical analysis of Australoid, Mongoloid, Caucasoid and Negroid are those of Johnson et al (1989, 1990).The following are lists of the major morphological features of the cranium and mandible that assist experts in distinguishing the major racial groups:
1. The Caucasian Cranium:
- Vault ranges from long, narrow and low to short broad and high;
- Rounded contour of the vault (anterior view);
- Mild to moderate development of the superciliary (supraorbital) brow ridges;
- A conical or hooked external occipital protuberance;
- Tortuous cranial sutures;
- Large mastoid and styloid processes;
- Straight (orthognathous) face (lateral view);
- Sharp lower lateral margin to the orbit;
- Narrow interorbital distance;
- Narrow and high bridge of the nose;
- Depressed nasofrontal suture;
- Prominent nasal spine;
- Sharp lower margin to the nasal aperture;
- Deep canine fossae;
- Pronounced chin;
- Carabelli's cusps, located on the mesiolingual surface of the maxillary molar teeth.
2. The Australian Aboriginal Cranium:
- Long narrow low vault (dolichocephaly), often with occipital bunning;
- Keeled contour (anterior view);
- Prominent glabella;
- Moderate to marked development of the superciliary brow ridges;
- Transverse occipital torus;
- Absent external occipital protuberance;
- Large mastoid processes;
- Zygomatic arches visible from above (phaenozygy);
- Blunt nasal spine;
- Guttering of the lower nasal margin;
- Moderate subnasal prognathism (anterior protrusion of the teeth);
- Antemortem avulsion of an upper incisor tooth
- Edge to edge bite;
- Poorly developed chin;
3. The Mongoloid Cranium (Chinese, Japanese, Korean, South East Asian, American Indian):
- Broad and flatened facial skeleton;
- Large prominent and angular zygomatic bones;
- Relatively short wide and high vault;
- Rounded contour of the vault;
- Flat glabella;
- Absent or slight development of the superciliary brow ridges;
- Simple cranial sutures;
- Minimal nasofrontal suture depression;
- Broad and flat root of the nose;
- Dull lower nasal margin with a short nasal spine;
- Absent canine fossae;
- Shovel-shaped upper incisor teeth;
- Short and wide palate and dental arcades.
4. The Negroid Cranium (American Negro, African Negro):
- Long narrow vault;
- Bregmatic depression;
- Rounded forehead;
- Wide interorbital distance;
- Wide and rounded nasal aperture;
- Little or no nasofrontal suture depression;
- Marked prognathism (anterior protrusion of the jaws).
5. The Polynesian Cranium (New Zealand Maori):
- High vault profile;
- Pentagonal shape when viewed from above or behind;
- Prominent parietal bosses;
- Keeling of the vault at the sagittal suture;
- Bitemporal narrowing of the vault;
- Visible zygomatic arches from above (phaenozygy);
- Flattened lateral surfaces of the temporal fossae and the malar bones;
- Vertical facial profile (orthognathism);
- Minimal dentoalveolar prognathism;
- Absent canine fossae;
- Large upper facial height;
- Presence of a rocker jaw (curved inferior border of the mandible)
- Absent antegonial notch;
- Reduced gonial angle (mandible).
- High and broad ramus of the mandible;
- Prominent chin;
RACIAL DETERMINATION FROM THE POSTCRANIAL SKELETON.
The postcranial skeleton has not been studied to the same extent as the cranium and mandible for racial allocation, but certain morphological features e.g. flattening of the shaft of some long bones, the curvature of others and the presence of squatting facets on leg and foot bones may provide supportive evidence of the possible ethnic origin of an unknown skeleton. Some experts claim that body and limb proportions are useful but St.Hoyme & Iscan (1989 p65) state that "intraseries variability in all races seems so great that the anthropologist should not depend too heavily on body proportions for his decisions."
Racial determination from postcranial remains has been attempted by Stewart (1962), DiBennardo & Taylor (1983), and Taylor et al (1984), but their reports indicate that these methods tend to be less accurate than methods based on the cranium and mandible.
AUSTRALIAN ABORIGINAL SKELETAL REMAINS - Recognition & Management
Aborigines have been living and dying in Australia for more than 40,000 years while European occupation has occurred only over the past 200 years. It is therefore inevitable that from time to time Aboriginal remains will be encountered and brought to the attention of the police. Such remains are regarded by living Aboriginal groups as sacred relics of their traditional culture.
In each Australian State, precontact Aboriginal remains are the subject of special legislation which governs the management of Aboriginal relics (bones or artifacts). At a skeletal investigation site of unknown origin, the need therefore exists initially to distinguish skeletal remains that may be the result of precontact or traditional Aboriginal burials, from those of more recent origin, and which may be the subject of possible coronial inquiry (Larnach & Macintosh 1967; Pounder 1984; Thorne & Ross 1986).
It is encumbent upon the police to try to establish whether unidentified human remains are of relatively recent origin (eg less than 50 years old) and therefore of potential forensic (coronial) interest. Remains that are more than 50 years old are probably of academic interest only, as even if it could be demonstrated that death occurred unnaturally or under suspicious circumstances, it is very unlikely that any criminal involved could be brought to justice after that length of time.
It is important that police officers throughout the country are also aware of the requirements of the State and Federal Legislation concerning ancient Aboriginal remains and of the attitudes and beliefs of modern Aborigines relative to the management of the remains of their ancestors.
Aboriginal remains of prehistoric origin come under the jurisdiction of the Cultural Record (Landscapes Queensland and Queensland Estate) Act 1987, No 90. and also under national legislation in the form of The Aboriginal and Torres Strait Islander Heritage Protection Act of 1986;. They may only be interfered with, under the direction and approval of the minister responsible for administering the act.
Crime scene officers must therefore:
try to establish the minimum age of the remains (ie the time since death).
be aware/suspect that unidentified human remains might be Aboriginal in
try to establish the Aboriginal origin of human remains “in situ” before
removal and transfer back to the laboratory.
set the correct procedures in motion to record and manage Aboriginal remains.
Racial characteristics of the Aboriginal skeleton have been studied and documented only for a few regional population groups such as Broadbeach (Qld), Roonka (SA), Kow Swamp (Vic), Murray River - Murray Black collection (NSW) and Coastal NSW. Following recent worldwide trends, Australian Aborigines also have been reclaiming the skeletons of their ancestors for reburial, and this is greatly inhibiting further studies that would assist in the clarification of Aboriginal skeletal variation, inter-relationships and origins.
ABORIGINAL SKELETAL CHARACTERISTICS:
The Cranium and Mandible
The cranial features of the Australian Aborigine have already been described. See p3 of these notes.
The Postcranial Skeleton (Fig.2)
Postcranial Aboriginal bones, especially of tribal origin, may display any or all of the following characteristics:
- squatting facets on the distal tibia and on the dorsal neck of the talus bone;
- posterior angulation of the proximal tibial plateau and posterior bending of the
tibial shaft (tibial retroversion and retroflexion respectively);
- antero-posterior flattening of the proximal femoral shaft (platymeria);
- mediolateral flattening of the tibial shaft (platycnemia);
- disarticulation trauma (especially at bone ends);
- chopped shafts of long bones (mortuary inquisition);
- bone arrangements into bundles;
- ochre staining of bones;
- heat effects on bone;
- forearm injuries from individual or tribal battles (healed fractures).
Most human skeletal remains are reported to the police who must establish site security, and treat the situation as a crime scene until proven otherwise. This would occur if the remains were proven to be of Aboriginal origin, if there were no suspicious circumstances surrounding the death of the person, and if the remains were shown to be of some antiquity ie death occurring more than 50 years ago, or from the pre-European contact period. Once this is established, the further control and management of the remains is handed over to officers of the Department of Heritage and Environment.
THE DETERMINATION OF PRECONTACT OR TRIBAL ABORIGINAL STATUS
If skeletal remains have been determined to be of Aboriginal origin, the investigator then must determine the precontact or tribal status of the remains before proceeding with further investigations. Such information may be derived from observations on the location and method of disposal of the remains, the nature of any associated artifacts both from within any burial pit or from the surrounds, and any characteristically Aboriginal features of the bones and teeth.
1. The Location and Method of Disposal.
The location may be a known Aboriginal burial site with records of previous
Aboriginal burial discoveries in the area. The manner of disposal of the bones will
be of traditional Aboriginal form:
a) Surface Remains.
These usually are readily recognisable from the context of the remains:
- cave burials, ossuaries, rock overhangs, log burials;
- tree or platform burials;
- mummified remains.
b) Subsurface Remains.
These tend to cause the most difficulty in the determination of Aboriginality.
Secondary burials (partly or completely disarticulated):
- bundle burials: complete or incomplete bundles of bones
usually in a vertical (occasionally
usually completely disarticulated;
occasionally only partly disarticulated;
- bundle cremations: a bundle of fragmented and charred bones;
Primary burials (fully articulated):
- articulated skeletons located in a trench or burial pit;
- extended supine, flexed or squatting positions;
- single or multiple burials (children occasionally included with an adult burial).
2. Associated Artifacts.
The absence of any non-traditional artifacts and the presence of any of the
following would suggest a traditional or non-recent Aboriginal origin of the
- stone: cores, worked tools, flakes, arrangements;
- animal bones and teeth: awls, dingo and marsupial tooth ornaments;
- remnants of mortuary feasts: skeletal remains of fish, dugong, goanna, wallaby,
possum, bird; shell, charcoal etc.;
- bark wrapping materials - especially in dry environments;
- ochre - staining on bones or in subjacent soils;
- evidence of neighbouring Aboriginal campsites, middens, hearths or rock
- presence of postcontact artifacts: buttons, metal objects, clothing, ornaments.
3. Skeletal and Dental Evidence.
- marked enamel wear with dentine and pulp exposure and apical abscess cavities;
- anterior dental avulsion especially of upper incisor teeth;
- evidence of bone fossilisation (mineralisation) or encrustations;
- absence of postcontact diseases: dental caries, tuberculosis, leprosy.
- absence of dental repair eg fillings, bridges caps etc
4. Other Evidence.
- stratigraphy: soil horizons, soil lenses, vegetation and root development
associated with the burial site;
- radioactive carbon dates.
Birkby WH 1966 "An evaluation of race and sex identification from cranial measurements." AJPA 24:21-28
DiBennardo R & JV Taylor 1983 "Multiple discriminant function analysis of sex and race in the The cranial features of the Australian Aborigine have already been described. Aboriginal postcranial bones especially of tribal origin may display any of the following characteristics:
postcranial skeleton". AJPA 63:305-314
Giles E & O Elliot 1962. "Race identification from cranial measurements." JFS 7:147-157
Howells WW 1970 "Multivariate analysis for the identification of race from the crania." In Personal Identification in Mass Disasters. Smithsonian Institute, Washington D.C., 111-123.
Johnson DR, O'Higgins P, Moore WJ & TJ McAndrew 1989 "Determination of race and sex of the human skull by discriminant function analysis of linear and angular dimensions." For Sci Int., 41:41-53
Johnson DR, O'Higgins P, Moore WJ & TJ McAndrew 1990 "Determination of race and sex of the human skull by Discriminant Function Analysis of Linear and Angular Dimensions - An Appendix." For Sci Int., 45:1-3
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Thorne A & A Ross 1986 "The skeletal manual: A handbook for the identification of Aboriginal remains." Produced by the N.P.W.S. and the N.S.W. Police Aborigine Liason Unit