Case 3 -
An Overview of Forensic Biological Anthropology
Professor, Department of Archaeology
Simon Fraser University
Click on each slide thumbnail image for an enlarged view
The traditional role of forensic biological anthropologists
With the advent of forensic molecular biology providing the potential for unequivocal personal
identification, one can question the role of forensic biological anthropology. Actually, our
contribution to forensic science and to understanding the biology of human hard tissues continues
Forensic anthropologists, at least in North America, are trained in anthropology programs which still
emphasize human biology, in its broad sense of human physical variation in space and time, as well as
archaeology with an explicit concentration on human material culture and site formation processes. These
perspectives form an excellent foundation for further training and experience with a forensic focus.
Moreover, the historic academic pillars of socio-cultural and linguistic anthropology furnish the
traditionally trained forensic anthropologist with a useful perspective for participation in forensic
anthropology in foreign locales.
There are several excellent textbooks which teach detailed human osteology (e.g., White 2000) as well
as juvenile osteology (e.g., Scheuer and Black 2000). Recent books which emphasize forensic osteology
describe the contribution that we can make to human remains identification (e.g., Byers 2002) as well as
the determination of circumstances around death (Reichs 1998). Compilations of enthralling case
histories can be found in Maples (1994), Fairgrieve (1999) and Steadman (2003). The significance of
natural and unnatural processes that diminish or alter evidentiary quality over time, a field of
scientific enquiry termed taphonomy, is treated in important works by Haglund and Sorg (1997, 2002).
Finally, the emerging role of archaeology, particularly in the realm of mass graves and human rights, is
receiving considerable attention (e.g., Sterenberg and Cox nd). It may not be adequately appreciated
that most archaeologists are experts in the assessment of landscapes including botanical evidence (e.g.,
tree ring analysis) and the recognition, collection, and curation of material culture (e.g., perishable
substances like cloth, leather and paper). Thus forensic evidence is conceptually congenial to most
archaeologists (Hunter et al. 1996).
Despite these positive features, it is fair to observe that the training of forensic anthropologists
is very uneven. Most skeletal biologists who provide forensic expertise have specialties, usually
forming the basis of their graduate studies, which are not generally shared. For example, not all
forensic anthropologists are capable archaeologists; many have no knowledge of botanical and
entomological evidence, nor experience with cremated remains, gunshot wounds or facial reproduction, for
example. Thus, pathologists may have to ally themselves with several biological anthropologists to
obtain the necessary breadth of forensic expertise. However, most of us are experts in altered states of
bone (and teeth); a knowledge area that is not duplicated in other medical and forensic disciplines.
Forensic biological anthropologists can contribute significantly to the tasks of evidence recovery from
crime scenes, determination of elapsed time since death as well as circumstances around the time of
death. Finally, we can reconstruct a lot about a person’s life before they died to assist in the
task of identification.
Our role in evidence recovery from crime scenes
What are archaeologists doing at crime scenes? Simply, we are experienced in mapping objects within
sites and using such observations to reconstruct behaviors that created the site. Central to our
expertise is an understanding of site formation processes. Typically, in domestic situations, sites are
fresh and have had little opportunity to change. Sites that contain skeletonized remains are usually
months or years old before they are investigated. Also, the decay and scattering of remains in such
sites have often had a large and disseminated impact on the scene and its environs. Sites change over
time. Only archaeologists have an understanding of site transformation processes on this scale. Perhaps
the single most important event in forensic anthropology in the past ten years was the release of
satellite photographs by US Ambassador to the UN, Madeleine Albright, in 1995 showing areas of disturbed
ground at many locations in the former Yugoslavia thought to be mass graves of individuals murdered in
the conflicts which raged from 1992 onwards. The Serbian authority’s response was to rob these
graves and bury the commingled, decomposed remains in numerous clandestine secondary graves. The
detection, excavation and recovery of a mountain of physical evidence including thousands of bodies, fell
to a select group of archaeologists and scenes of crime officers (SOCO’s). From this experience
has emerged an increasingly sophisticated discipline of forensic archaeology (Skinner et al. 2003).
A myriad of major factors (e.g., carnivores and rodents) and minor factors (e.g., root acids)
seriously affect bones. The essential role of the forensic taphonomist is to distinguish natural
postmortem processes from unnatural perimortem processes in a rigorous exercise of differential
diagnosis. In this way the pathologist may be prevented from overdiagnosing damage to remains.
The sine qua non of archaeological method is the recording of spatial relationships based on the
fundamental principle that usually the older stuff tends to be at the bottom of a deposit. Experience
with this principle enables the archaeologist to recognize and record site disturbances, both natural
(e.g., rodent action, slumpage) and unnatural (re-visits by a perpetrator). It is important to
distinguish between simple two-dimensional mapping, typically using a grid system, familiar to many
evidence officers who deal with, for example, motor vehicle accidents and plane crashes versus
three-dimensional mapping which is essential for the archaeological reconstruction of spatio-temporal
relationships in buried remains. Another key concept in archaeology is “association”. In a
forensic context, the relationship among objects including deposits, is central to documenting the
significance of abnormal anatomical relationships due to disarticulation from dismemberment (e.g.,
CH-East Timor) as well as decompositional movement producing dissociation of skeletal elements (e.g.,
secondary mass grave sites). An interesting example of association is afforded by the abnormal
occurrence of a mass of fly pupae inside a cranium due to its having been breached by a fatal blunt
impact (case history (CH) to be presented).
The primary skill of the anthropologist is in recognizing and interpreting varying and altered states
of bone. Such alteration occurred both during the individual’s lifetime (e.g., innate traits of
ancestry, sex and stature; as well as acquired features such as robusticity or healed fractures); around
the time of death (e.g., gunshot wounds and cut marks); and, subsequently, due to various influences such
as cremation, (re)burial, decomposition, scavenging and weathering.
The method of killing and subsequent treatment of the dead by a perpetrator are very important in
determining circumstances surrounding death and to the ultimate determination of the cause and manner of
death. While legally and historically, the latter judgments are the province of the pathologist and
medical examiner/coroner, both the archaeologist and anthropologist often encounter evidence germane to
this question. The archaeologist is able to distinguish among the following site types: execution site,
surface disposal, primary grave, secondary grave, disturbed and looted grave, cremations and so on
(Jessee 2003). Cavalier and disrespectful disposal of bodies can be recorded archaeologically as can the
presence of ballistics. Dislocation of the neck due to unskillful hanging in East Timor created evidence
that could only be recorded at the time of excavation (CH). Conceivably one could try to preserve this
abnormal anatomical relationship until the body could be examined by a pathologist back in the morgue, as
is done in the case of ligatures by wrapping the forearms and hands in Saran Wrap around the wrists-a
novel, if routine, practice during the exhumation of Srebrenica victims by teams fielded by the
International Criminal Tribunal for the former Yugoslavia. In one homicide case here in British
Columbia, the police investigators encountered head hair distributed throughout the grave fill; an oddity
explained by the absence of the head which the perpetrator had removed at a second excavation weeks after
decomposition had started.
Archaeologists are familiar with keeping records of artifacts and so the creation of evidence catalogs
designed expressly for the purposes of maintaining a chain of custody, comes easily. Similarly,
archaeologists are trained in the recognition of botanical evidence that may bear upon the determination
of seasonality and elapsed time since death. Many have taken instruction in pollen analysis and
dendrochronology. An interesting application of the latter knowledge occurred in Serbia where transport
of bodies in large trucks down narrow wooded paths broke branches leaving a permanent record of its
timing as the trees healed their wounds.
Our role in identification
The first determination expected of the anthropologist is whether the bones are human or not. The
human skeleton is unique compared to other mammals by virtue of its adaptiveness for bipedal locomotion
combined with an enormously enlarged cranium coupled with a tiny dentition. Even small fragments of the
face, skull and postcranial skeleton bespeak these differences. Another unique human attribute is our
delayed maturation such that it takes us three or four times longer to grow up and ultimately die than it
should for our body size. The important forensic consequence of this physiological difference is that at
the histological level our bones are dominated by highly remodeled haversian bone. So it is usually
quite easy for an anatomist to recognize human bones, even in small pieces, unequivocally.
The core expertise of the human osteologist is to provide opinions as to ancestry, sex, stature and
age at death. While each of these remains an area of active research, as can be attested by any issue of
the forensic science journals, here I will emphasize only new advances or important perspectives that the
non-specialist should have on the anthropologist’s contribution.
The whole concept of ancestry determination in forensic anthropology has been severely critiqued in
recent years (e.g., Goodman 1995). There is frank recognition that while society recognizes bounded
categories (Black, White, Whatever), human beings belong to unbounded genetic clusters which grade more
or less imperceptibly into another with only the extremes being visibly different. Consequently,
biological attribution may bear little resemblance to social categorization. Complicating this picture
is the recent widespread mixing of populations drawn from all over the world. Investigative methods for
the anthropologist include morphological analysis, osteometrics and minor anatomical variants of the
skull and dentition. The interested pathologist can read the methods in Gill and Rhine 1990, Turner et
Sex attribution from just bones, including those of children, has been revolutionized by recognition
of the amelogenin gene (Slavkin 1997). Except in rare cases of the complete absence of cellular
structure (e.g., cremations), this is the preferred method. Of interest, however, are those not
infrequent cases in which cellular sex does not match with skeletal markers especially of the face. In
the author’s personal experience, undeniably female individuals had skeletons which looked rather
masculine (biker gang case, sex trade worker). One wonders why.
I suspect that stature determination from limb bone length is largely a waste of time. We know that,
approximately 80% of missing persons have statures falling within two standard errors of the predicted
value (Skinner 1988); so unless the bone is from an extraordinarily short or tall person, estimating
stature is not individualizing at all. With that said, osteometry of the limb bones continues to be
forensically useful in cases of limb asymmetry (e.g., in brachial plexus nerve damage at birth, or nerve
damage due to limb fracture in childhood).
Determination of age at death is the thing anthropologists do best (although not very well). It is
our most active area of research because of our wish to reconstruct accurately the demographics of
ancient skeletal populations. Most of our age markers have correlations with real age of 0.8 or worse
which really means we can only slot the missing person into one of two categories (young vs. old adult).
Two observations give me hope. Firstly, when one has multiple age indicators (e.g., medial clavicle,
pubic symphysis, auricular surface, vertebral centrum surface, root translucency, joint lipping, tooth
loss), the age at death estimates (usually given as a 10 year range) almost always have been shown to
include the actual age (personal experience working with Srebrenica individuals). Secondly, recent work
strongly suggests that cementum increments on tooth roots are indeed annual (Wittfer-Backhofen et al. on
line) with a correlation between predicted and actual age of 0.97. This is very encouraging.
Forensic cases form a mortality cohort which differs biologically (and socially) from the general
population; for unexplored reasons, they tend to have been socially and nutritionally marginalized from
early on in life such that their developmental environment is less than optimum. Thus it is important
for the death investigator to keep in mind that in forensic work one will encounter negative skeletal and
dental conditions more commonly. Thus, we have observed osteopenia of facial bones in children drawn
from recent immigrant populations to Canada (the marker of this is localized hypoplasia of the primary
canine tooth) (Skinner et al. 1994), markedly pinched or cleft palates (CH-SS case), dental crowding, as
well as lines of disturbed growth in the enamel (CH-Skinner and Anderson 1991) and frank enamel
hypoplasia (CH-SC). Distinctively negative hard tissue sequelae may help identify someone or may provide
evidence of chronic child abuse or neglect prior to death of a child.
Our role in determining elapsed time since death
Few forensic anthropologists feel comfortable with estimating elapsed time since death from
decompositional changes, except crudely and rather uselessly. But the forensic archaeologist can play a
very useful role in recognizing and recovering botanical evidence including severed tree roots, for
example, or pollen which can show seasonality or exotic origin. We have learned in Canada to defer to
the essential expertise of the forensic entomologist in deaths less than a year or two old.
Our role in determination of manner and cause of death
Most osteologists are entirely comfortable with the recognition of postmortem damage to bones;
so-called taphonomic changes. Typically, this is due to animal chewing and gnawing (CH-Stanley Park
case). More problematic is the recognition of antemortem bone changes that occurred a few weeks or
months before death(CH-Knox Mountain) and distinguishing these subtly remodeled bone changes from
unremodeled perimortem events. The impact of perimortem trauma on bones is an active research area in
human skeletal biology; so pathologists could draw useful expertise from this quarter. For example,
crack intersections forming a “T” permit the sequencing of blunt impacts to a skull (CH).
The complexities of disintegrating joint integrity in the upper cervical region can be revealed by
examination of repeated machete blows to the neck (CH). Bone is a remarkably useful medium for recording
faint striations that can be linked back to the cutting edges of particular axes (CH). One of our
students has recently undertaken a study of oral gunshot wounds to determine if bilateral fracture of
mandibular coronoid processes could be also produced by carnivore chewing. The answer is
‘no’ (Puskas 2003). Interestingly, a British pathologist colleague has observed that
American anthropologists have more experience with GSW’s than do British pathologists. In another
case from East Timor the investigators mistakenly at first diagnosed a protruding piece of metal in the
wrist as an electrode from some kind of torture apparatus when in actuality it was a defense wound from
clipped nail shot in a homemade shotgun (CH).
It is important to create and maintain a functional link between anthropologists and forensic
pathologists. In my experience this has not been easy. The bridge between these two intellectual
communities is often the medical examiner’s office whose staff changes frequently and
communications are lost. Also, it seems pathologists change posts remarkably often, while tenured
anthropologists tend to be restrained by golden handcuffs.
Forensic anthropologists are experts in bone; but we have to be able to see it. I am curious how
often forensic pathologists decide not to engage an anthropologist in examination of remains simply
because of the time it would take (a few days) to render the flesh from the bones. We have found that
the use of instant, two-component spray glues will allow complete reconstruction of a multiply shattered
cranium in less than an hour; greatly enabling the pathologist’s reconstruction of entrance, exit
and number of GSW’s.
We have found in mass grave work that the responsibility for examination of the dentition and any
dental work is relegated all too often to the more or less reluctant pathologist and, typically, the
ultra-keen ingenue anthropologist who can hardly wait to get at the teeth. Even though many pathologists
and anthropologists have considerable experience with the mouth and the teeth, we believe that this
aspect of forensic science, particularly as it occurs in an international context, is sufficiently
complex and important that only richly experienced forensic odontology specialists augmented with local
knowledge are equipped to meet the challenge (Skinner and Alempijevic 2003).
Another area in which we feel anthropologists fail to recognize evidence in skeletonized remains is
bone marrow that may contain drug or chemical residues. Many such substances can be found in bone marrow
months or even years after death (Raikos et al. 2001) and significantly bone marrow is second only to
blood as a proxy tissue to determine toxicity. This area needs further research.
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