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July 1990
THE FORENSIC ANTHROPOLOGIST
By
Robert W. Mann, M.A.
and
Douglas H. Ubelaker, Ph.D.
Physical Anthropologists
Department of Anthropology
Smithsonian Institution, Washington, D.C.
In recent years, just as the investigation of a crime scene
has become more complex and sophisticated, so has the task of the
forensic anthropologist. Forensic anthropologists assist medical
and legal specialists to identify known or suspected human
remains.
The science of forensic anthropology includes archeological
excavation; examination of hair, insects, plant materials and
footprints; determination of elapsed time since death; facial
reproduction; photographic superimposition; detection of
anatomical variants; and analysis of past injury and medical
treatment. However, in practice, forensic anthropologists
primarily help to identify a decedent based on the available
evidence.
For example, when a skeleton found in a wooded area is
brought to a morgue or an anthropologist's laboratory for
examination, the first step is to determine whether the remains
are human, animal, or inorganic material. If human, an
anthropologist then attempts to estimate age at death, racial
affiliation, sex, and stature of the decedent.
If the skeleton shows evidence of prolonged burial or
is accompanied by coffin nails or arrow points, it usually
represents an historic or prehistoric burial rather than a recent
death. Construction crews frequently unearth such skeletons
during road or housing excavations. After combining all of the
evidence, the anthropologist determines the skeleton's possible
significance to medical and legal authorities.
Although the primary task of anthropologists is to establish
the identity of a decedent, increasingly they provide expert
opinion on the type and size of weapon(s) used and the number of
blows sustained by victims of violent crime. It should be noted,
however, that forensic pathologists or related experts in
forensic medicine determine the cause or manner of death, not the
forensic anthropologist.
Most anthropologists have advanced degrees in anthropology
and have examined hundreds of remains. They are also thoroughly
familiar with human anatomy and how it varies in different
populations. Some anthropologists may also have experience in
police science or medicine, as well as in serology, toxicology,
firearms and toolmarks identification, crime scene investigation,
handling of evidence, and photography. A limited number of
anthropologists deal with footprint analysis and species
identification of carrion insects in relation to estimating time
elapsed since death.
Perhaps the anthropologist's most valuable skill is
familiarity with subtle variations in the human skeleton.
Although most adult skeletons have the same number of bones
(206), no two skeletons are identical. Therefore, observations
of patterns or unique skeletal traits frequently lead to positive
identifications. The most frequently used method for
identification is to compare before- and after-death dental
photoimages. If such photoimages do not exist, or if they are
unavailable, then old skeletal injuries or anatomical skeletal
variants revealed in other photoimages may provide the
comparative evidence necessary to establish a positive
identification.
HYPOTHETICAL EXAMPLE
Suppose hunters find a partially clothed skeleton lying on
the ground in a heavily wooded area with much of its clothing
torn and scattered by carnivores. Law enforcement officers are
called to the scene, as is the medical examiner or nonphysician
coroner. The scene is photographed in detail, and the skeleton
is examined and photographed before being removed to the city
morgue.
At the morgue, the medical examiner examines the remains for
evidence of trauma, such as stab marks in the shirt, blunt trauma
to the skull and mandible, and broken bones. Photoimages and
photographs of the body show that no bullets or pellets having
been noted. Also, examination of the clothing reveals no wallet
or other personal identification.
The medical examiner determines through measurement of the
pubic area that the remains are those of a middle-aged adult
male. There is no evidence of facial or head hair to aid in
determining racial affiliation. From measurements taken at the
scene, the examiner roughly estimates the stature. Also, a
forensic odontologist is called in to take dental photoimages.
Although the decedent has a number of large dental cavities, he
shows no restorations or evidence of having seen a dentist. At
this point, the medical examiner requests assistance from a
forensic anthropologist, who conducts further study of the
remains in the laboratory.
The forensic anthropologist's examination confirms the
medical examiner's findings that the individual is a middle-aged
male. However, questions remain that the forensic anthropologist
must answer, such as:
. What is the individual's racial affiliation?
. What is the individual's age and stature?
. How long has the individual been dead?
. Is there any evidence of trauma or foul play at or near the
time of death?
. Are there any distinguishing skeletal traits that may aid in
establishing the identity?
. Is there any indication of post-mortem treatment or
alteration of the remains?
Racial Affiliation
The question of racial affiliation is difficult to answer
because, although racial classification has some biological
components, it is based primarily on social affiliation.
Nevertheless, some anatomical details, especially in the face,
often suggest the individual's race. In particular, white
individuals have narrower faces with high noses and prominent
chins. Black individuals have wider nasal openings and subnasal
grooves. American Indians and Asians have forward-projecting
cheekbones and specialized dental features.
Examination of this skeleton reveals traits consistent with
white racial affiliation. Further examination of the skull
produces a few strands of straight blonde hair. Microscopic
examination shows the hair to be consistent with that of a white
person.
Age and Stature
Usually, examination of the pubic bone, sacroiliac joint,
amount of dental wear, cranium, arthritic changes in the spine,
and microscopic studies of bones and teeth narrows the age
estimate given by the anthropologist. After examining the
skeleton, these indicators suggest that the man was between 35
and 45 years of age at the time of death.
Estimation of stature can be narrowed by measuring one or
more complete long bones, preferably a femur or tibia. If
stature estimates are based on incomplete long bones, less
confidence can be placed in them. This measurement of the
maximum length of the bone can then be plugged into a formula
based on race and sex to produce an estimate. In this case the
individual's stature was estimated at 5'7'' to 5'9'' with a mean
stature of 5'8.''
Time Interval Since Death
Estimating the time interval since death can be extremely
difficult. For the most part, such an estimate is based on the
amount and condition of soft tissue, such as muscle, skin, and
ligaments present, the preservation of the bones, extent of
associated plant root growth, odor, and any carnivore and insect
activity. However, many other variables must also be considered,
including the temperature at the time of death, penetrating
wounds, humidity/aridity, soil acidity, and water retention. The
longer the time since death, the more difficult it is to
determine the time interval since death. In this hypothetical
example, the anthropologist determined that the individual died
6 to 9 months previously, based largely on the condition of the
soft tissue and the amount of root growth in the individual's
clothing.
Evidence of Trauma
After the dirt and forest debris were removed from the bones
using water and a soft brush, a number of faint cuts became
visible in the left ribs and the mid-back. The number of
discrete cuts in three ribs and in one vertebra suggest that this
male was stabbed a minimum of three times. No additional
evidence of trauma was noted.
Distinguishing Skeletal Traits
Further examination revealed that the male sustained a
fracture above his right eye and upper jaw bone at least several
years before death. The individual also had a severely deviated
nasal septum and presented evidence of a severe chronic nasal
infection. This observation is noteworthy because if he sought
medical help for the fractures or sinus condition, photoimages
may have been taken that would provide an excellent opportunity
for positive identification.
POST-EXAMINATION PROCEDURES
After the forensic anthropologist completes the
examination, the medical examiner provides all information
obtained from the skeleton to the law enforcement officials
investigating the case. The information is then entered in the
National Crime Information Center (NCIC).
In this hypothetical case, after several months, a search
failed to locate a missing person matching this description.
Therefore, the medical examiner and the detectives returned to
the forensic anthropologist to request that a facial
reproduction be attempted.
Two approaches are available to an anthropologist in
reconstructing facial appearance during life. First, the
anthropologist could work with a composite artist experienced in
rendering sketches based on information supplied by eyewitnesses.
Or, the anthropologist could call in a specialist in
three-dimensional facial reproduction, a technique in which the
head is constructed in clay directly over the skull and mandible
or over good casts of them. Because of limited funds, and
because an experienced composite artist is available on staff,
the forensic anthropologist and artist worked together to produce
a drawing of the person represented by the skeletal remains.
This drawing was then made available to the public via the local
media.
Shortly thereafter, two unrelated men who had seen the image
on television came forward because they thought that it might be
a relative. Medical and dental records for both individuals
could not be located, but facial photographs taken within the
last 2 years were available.
Using new techniques of photographic superimposition and
comparison, the forensic anthropologist excluded one of the
individuals outright. However, frontal photoimages of the second
individual taken 3 years before death showed the individual was
treated for facial injuries sustained in a motor vehicle
accident. The configuration of the frontal sinuses on the
photoimages matched exactly the photoimages of the recovered
skull, thereby positively identifying the victim.
VALUE OF FORENSIC ANTHROPOLOGY
A forensic anthropologist makes significant contributions to
an investigation. The greatest of these could well be the
anthropologist's intensive training and experience in
distinguishing between human and nonhuman remains, determining
age at death, racial affiliation, sex, stature, elapsed time
since death, skeletal trauma, post-mortem damage and alteration
of the skeleton, and establishing positive identification based
on skeletal and dental evidence. Such information can be
obtained from complete bodies or those partially destroyed by
burning, air crashes, intentional mutilation and dismemberment,
explosions, or other mass disasters. In fact, a forensic
anthropologist is now an integral member of most mass disaster
teams.
Through their anthropological training, most forensic
anthropologists have knowledge of excavation techniques and
mapping that are invaluable in recovering evidence.
Consequently, the forensic anthropologist should participate in
the investigation of the crime scene and, especially, in the
recovery of human skeletal remains.
CONCLUSION
Many forensic anthropologists offer their services to law
enforcement agencies, coroners, and medical examiners. However,
if a law enforcement agency does not have access to a forensic
anthropologist, experienced experts can be found in many of the
larger universities, in anthropology museums throughout the
United States, and in some medical examiner's offices. It should
be noted, however, that not all physical anthropologists are
qualified to practice forensic anthropology. A list of board
certified forensic anthropologists can be obtained from the
American Academy of Forensic Sciences. Forensic anthropologists
have much to contribute to law enforcement and would welcome
the opportunity to assist in the successful resolution of an
investigation.