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October 2000 Volume 2 Number
4
Presentations at the
9th Biennial Scientific Meeting of the
International Association for
Craniofacial Identification
Washington, DC
July 24–28, 2000
Part 3
The following abstracts
of the presentations are ordered alphabetically by authors' last
names.
Quality Standards
for Forensic Opinions on the
Identity of Living Offenders In Pictures
F. W. Rösing
Institut für Humangenetik und Anthropologie Universitatsklinikum
Ulm, Germany
The forensic identification
of persons in photographic documents follows established scientific
criteria and methods. The recognition of human faces, however,
is a highly developed, natural human skill. The widespread belief
that a professional forensic identification is as easily accomplished
as common facial recognition among individuals is problematic.
In response to the problems generated by this mistaken belief,
a group of university-based experts has formulated a set of quality
criteria for such identification opinions. The goal of these
criteria is the creation of an identification system that can
be peer-reviewed for expertise. The criteria are as follows:
- The main principle of photographic
identification is the assessment of detailed structures in a
slow and thorough process and with a gradation of the result,
as opposed to holistic, fast, and polarizing daily recognition.
- The country-specific judicial
basis must be considered.
- Photographic cameras are
recommended for surveillance equipment as video cameras have
too low a resolution. A surveillance camera should not be installed
too high above the scene because this reduces recognition of
the lower face. For an identification, comparison pictures of
the suspect should be made, preferably with the original security
camera. An identification should be performed by picture-to-picture
comparison and not by a picture-to-person comparison.
- The picture quality influences
recognition. This is an independent variable that must be assessed
in every extracted trait parallel to the assessment of the trait
itself.
- Identifying traits are morphological
structures that can be seen on the surveillance picture, particularly
those of the face and ears, but also of the thorax or hands,
or of stature and posture. Population frequencies are decisive
in the assessment of traits, and the possibility of a secondary
change of traits (e.g., through use of a mask or other means
of obfuscation) should be considered.
- The expert opinion may explain
the scientific bases of photographic identification. All traits
found must be described, preferably using established anthropological
nomenclature, but with due regard that the opinion should be
understood by non-experts. Partial expert commissions—for
example, of an ear-should not be accepted. All principles used
and assumptions made must be described through every step of
the identification process. The result of an expert opinion is
the identity probability.
- The identity probability
depends upon the number and rarity of the traits found. If traits
are independent from each other, the single probabilities are
multiplied according to the usual probabilistic rules; if the
traits are correlated, the covariance reduces probability. If
trait frequencies are not formally known, they should be estimated.
For the final probability result, a verbal formulation should
be given, possibly also a figure, together with the range.
- The principle of preselection
must be considered. The normal probability assessment depends
upon the assumption that a suspect is a chance draw from the
general population. If he or she has been found using the surveillance
photograph, this is not a chance draw. Then every suspect named
is similar to the offender. Consequently, the population-based
probability assessment can not be applied, but the demands for
rarity of traits increases, and traits that are normally not
included in the recognition of persons, such as the ear traits,
become important.
- As a general precaution,
the possibility that a close genetic relative might also be suspected
should be checked. He or she should be included in the identification
process.
- The scientific basis of
photographic identification is physical anthropology, which includes
as a subfield the morphology of living persons. The assessment
of external traits formerly used to diagnose paternity is particularly
useful as a basis. A medical doctor or criminalist might acquire
and develop the necessary knowledge and experience of physical
anthropology during work on scene or in the field.
Several procedural steps
are recommended for quality assurance, including regular determination
of the intra- and inter-observer error, the exchange of model
cases, consultation with colleagues before opinions are issued,
and the examination of new members.
References
Buhmann, D., Helmer, R. P.,
Jaeger, U., Jürgens, H. W., Knussmann, R., Rösing,
F. W., Schmidt, H.D., Szilvássy, J., and Ziegelmayer,
G. Standards für die anthropologische Identifikation lebeder
Personen auf Grund von Bilddokumenten. Grundlagen, Kriterien
und Verfahrensregeln für Gutachten, Anthrop Anz (1999)
57(2):185–191. (Also published in Dt. Autorecht
[April 1999], pp. 188–189; Kriminalistik [April 1999],
pp. 246–248; Neue Z. Strafrecht NStZ [1999] 5:230–232;
Rechtsmed [1999] 9:152–154.)
Back to the index
Radiographic
Identification: Importance and Cases
F. W. Rösing,
R. Novak, T. Fleiter, R. Hausmann, and K. W. Alt
Institut für
Humangenetik und Anthropologie Universitatsklinikum
Ulm, Germany
The differential value of
the dentition in the identification of unknown skeletons has
been reevaluated in several recent studies. These studies included
a thorough check of existing dental records in which more than
one third of all single file entries were either wrong or missing
(Hausmann et al. 1997). Moreover, the publication of the dental
records of unknown recovered bodies yielded an identification
success rate of only five percent (Alt and Walz 1999). These
data challenge the widespread opinion that teeth have a decisive
value for human identifications and add new weight to the ancient
practitioner's rule of using every technique available for identification.
In northern countries, the
classic technique of radiology is used as an alternate means
of identification. For various diagnostic purposes a large portion
of the population has been X-rayed, and the films are normally
stored. Skull, thorax, spinal column, and pelvic girdle are the
skeletal regions most frequently used in comparisons, but the
clavicle, sternum, patella, and calcaneus are diagnostic as well
(see Case A, below). The strong individuality of the anatomical
structures depicted in these radiographs and the clear and direct
diagnostics of this technique are highly valued for identification
purposes.
Problems associated with
radiographic comparisons include:
- Low quality clinical films,
such as those revealing little antemortem evidence;
- Variability in the orientation
of skeletal remains between the clinical and postmortem images;
- The presence of overlapping
trabecular structures (Case B);
- The presence on ontogenetic
changes (Case C); and
- The digital storage of Roentgen
films, which allows the possibility of image manipulation and
a consequently drastic reduction in their value as forensic documents.
Case A: The Identifying Vertebra
A mummified body was found
hanging in a tree 11 years after death. A missing man was linked
to the body following analysis of age, sex, and stature, but
no dental records were available and impeding mummified tissues
made facial identification imprecise. Final identification was
achieved through analysis of radiographs showing identifying
traits in the lower vertebrae and sacroiliac fusion.
Case B: The Shredded Body
Parts of a fresh body were
found in a garbage processing plant
between the coarse and fine shredders. Sexing and aging of the
remains were difficult, and there were no remaining teeth. Portions
of the jaw were present, however, and identification was possible
using the trabeculae of the mandibular body.
Case C: Blurring Growth
The skeletonized body of
a young person was found in a forest approximately 18 months
after death. The sex, age, and stature of the skeleton were linked
to that of a missing girl for whom no dental records were available.
Identification, complicated by ontogenetic changes visible in
the elbow region, was accomplished through analysis of strongly
individual facial traits.
References
Hausmann, R., Liebler, M.,
and Schellmann, B. Dental records as an aid to identification:
Quantity and quality of dental documentation, Rechtsmedizin
(1997) 7(3):88.
Alt, K. W. and Walz, M. Dental
print media and their value if forensic odontology, Journal
of Forensic Odonto-Stomatology (1999) 17(1):5–9.
Preliminary
Study on Facial Soft Tissue Thicknesses by
Magnetic Resonance Imaging (MRI) on Northwest Indians
D. Sahni, I. Jit,
D. Sanjeev, P. Singh, S. Suri, and H. Kaur
Postgraduate Institute of Medical Education and Research
Chandigarh, India
It is not uncommon for the
police to need to identify the deceased from a skull. If data
on facial soft tissue thicknesses is available, a facial reconstruction
may be done. Work of this nature has been performed in Western
and Japanese populations (Rhine and Campbell 1980), but the methods
used lacked adequate reliability, and the data generated from
one population cannot be extrapolated to another population.
No work on this subject has been done in India, where previously
only the approximate age and sex of the skull (Jit 1979) and
sometimes the cause of death (Jit 1993) could be determined.
Lack of data for the Indian population resulted in the inability
to accurately reconstruct facial features from skeletal remains,
and, consequently, many murder cases could not be traced. It
is important to find out the facial soft tissue thicknesses in
various populations in India.
In Japan and Western countries,
the following methods have been used for measuring facial soft
tissue thicknesses:
- Needle depth probe method
on cadavers (His 1895; Kollman and Buchly 1898);
- Radiography, including computerized
tomography (CT) scan (Aulsebrook et al. 1996; George 1987; Philips
and Smuts 1996);
- Ultrasonography (Lebedinskaya
et al. 1993); and
- Magnetic resonance imaging
(MRI).
MRI offers several advantages.
It allows multiple planes for study, thus allowing accurate measurements
perpendicular to the area of interest. A greater number of anatomical
points can be studied accurately using MRI as compared to CT
scans. The soft tissue details are much better on MRI as compared
to CT scans. In the present preliminary study, measurements of
soft tissue thicknesses by MRI were taken at 29 fixed anatomical
points in 30 male and 30 female northwest Indian adults. The
following sections were taken into consideration to measure the
tissue thicknesses at various anatomical points in the MRI:
- Sagittal section studies
included supraglabella, glabella, nasion, end of nasal (rhinion),
midphiltrum, upper lip margin, lower lip margin, chin lip fold,
mental eminence, beneath chin, vertex, inion, and opisthocranion.
- Parasagittal section at
the level of mid-orbit studies included frontal eminence, supraorbital,
and infraorbital on both sides.
- Coronal section studies
included right porion, left porion, right gonion, and left gonion.
- Transverse section studies
included right zygion, left zygion, right outer canthus, left
outer canthus, right supra M2, and left supra M2.
- The additional eight landmarks
measured were not studied by other authors.
Mean values of the measurements
show that in the northwest Indian population, the measurements
are quite different from that described in European populations
(Rhine and Campbell 1980). Differences were particularly noted
in the landmarks at glabella, nasion, midphiltrum, mental eminence,
supraorbital, infraorbital, and zygion.
References
Aulsebrook, W. A., Becker,
P. J., and Iscan, M. Y. Facial soft tissue thicknesses in the
adult male Zulu, Forensic Science International (1996)
79:83–102.
George, R. M. The lateral
craniographic method of facial reconstruction, Journal of
Forensic Sciences (1987) 32:1305–1330.
His, W. Johann Sebastian
Bach's Gebeine und Anlitz nebst Bemerkungen uber Dessen Bilder,
Abhandlung durch Mathematik und Physik (1895) 22:380–420.
Jit, I. The House of Skeletons
case, Journal of the Anatomical Society of India (1979)
28:106–116.
Jit, I. Case report: Dr.
Mela Ram's murder case in Chandigarh, Journal of the Indian
Academy of Forensic Medicine (1993) 14:11–14.
Kollmann, J. and Buchly,
W. Die Persistenz der Rassen und die Reconstruction der Physiognomie
Praehistorischer Schadel, Archiv fur Anthropologie (1898)
25:329–359.
Lebedinskaya, G. V., Balueva,
T. S., and Vaselovskaya, V. S. Principles of facial reconstruction.
In: Forensic Analysis of the Skull: Cranio Facial Analysis,
Reconstruction and Identification. Eds. M. Y. Iscan and R.
P. Helmer. Wiley-Liss, New York, 1993, pp.183–198.
Phillips, V. M. and Smuts,
N. A. Facial reconstruction: Utilization of computerized tomography
to measure facial tissue thicknesses in a mixed racial population,
Forensic Science International (1996) 83:51–59.
Rhine, J. S. and Campbell,
H. R. Thickness of facial tissues in the American Blacks, Journal
of Forensic Sciences (1980) 25:847–858.
Back to the index
Variation
of the Glabella Profile by
Roentogenographic Cephalometry in Northeast Asians
R. Sakashita,
N. Inoue, and T. Kamegai
Kumamoto University
Kumamoto, Japan
There are many variations
of the glabella profile used to identify persons and racial origin.
Among the Japanese, two major facial types are hypothesized:
the Jomon type with prominent glabella and the Yayoi type with
flat glabella (Hanihara 1999). This study was conducted to test
this hypothesis and also to discover the range of variation in
northeast Asians.
Materials and Methods
A total of 812 male crania,
comprised of the following, were used:
- 18 Japanese groups from
the northeastern to the southern islands of Japan, from the Jomon
period (8000–3000 YBP) to the present, housed at the University
of Tokyo, Kyoto University, Kyushu University, and Nagasaki University;
- 1 Korean group housed at
Kyoto University; and
- 2 Chinese groups from the
northeast to the root of the Yellow River, from 7000 YBP to 1800
YBP, housed at the Chinese Academy of Social Science.
X-rays of all possible cases
were used. To clarify the shape of the glabella, seven angular
measurements and seven linear measurements (Inoue et al. 1997)
were made. The significant difference among group means was tested
using GLM and Tukey's procedures. Fast-cluster was used to classify
the samples into two groups: the prominent glabella group and
the flat glabella group.
Results and Discussion
The means of all measurements
among groups were found to be significantly different by GLM
(p < 0.0001). The distance from the nasion to the tangent
line of nasal bone at the nasion was greater among Japanese groups
(M = 5.5–11.9 mm) than among Chinese and Korean groups
(2.2– 5.2 mm), with the exception of Japanese groups from
the Yayoi and Kofun periods (2200–1500 YBP, 3.1–5.9
mm). The distance from the nasion to glabella-metopion was greater
among the eastern Japanese groups in the Jomon period and the
upper Yellow River (8.7–9.7 mm) than among groups from the
Kofim period (4.8–7.7 mm), other groups of the Yellow River,
and Korea (6.8–7.7 mm). The tangent of frontal bone at the
nasion to glabella-metopion was acute among the eastern Jomonese
and wide among groups in the Yayoi and Kofun period.
In the Jomon period, most
samples from the northeast and east were classified into the
prominent glabella group; however, the rate was reduced in the
west. In the Yayoi period, more than 70 percent of samples in
Kyushu were classified into the flat group; in the southern island,
63.6 percent were classified into the prominent glabella group.
In the Kofun period, most Japanese samples were classified into
the flat groups. In the Medieval period, almost 60 percent of
samples were classified into the prominent glabella group. More
than 70 percent of the Chinese groups were classified into the
flat groups; however, in the upper Yellow River, the rate was
reduced to 30 percent. All Korean samples (n = 10) were
classified into the flat group.
Compared to Chinese groups,
in which the majority of samples were classified into the flat
group with few exceptions, there were variations among Japanese
samples. The shape of the glabella would be affected by the pressure
of the frontal sinus, which might be affected by the environment.
It was suggested from this result that the shape would not be
related to the environmental temperature or moisture. The variation
in Japanese glabella shape fits the hypothesis of a migration
of people with a paddy-rice agriculture from Korea to eastern
Japan at the time of the Yayoi period. However, it is uncertain
why there were the flat glabella groups in Kyushu in the Jomon
period.
References
Hanihara, K. Jomonese face
and Yayoi face (in Japanese). In: Scientific Approach to the
Face. Eds. Baba, H. and Kanawawa, E. Newton, Tokyo, 1999,
pp. 68–85.
Inoue, N. Materials and methods
of investigation. In: Tooth and Facial Morphology of Ancient
Chinese Skulls. Eds. Inoue, N. et al. Therapeia, Tokyo, 1997,
pp. 17–34.
Back
to the index
Identification
of Sex From the Quantification of the Mandibular Size and Shape
Through Use of
New Developments in the Elliptic Fourier Method
M. Schmittbuhl
and P. Mangin
Institut Universitaire de Medecine Legale
Lausanne, Switzerland
M. Perrier
Policlinique Medicale Universitaire
Lausanne, Switzerland
Sex identification has been
investigated in nearly every part of the skeleton. However, data
dealing with sexual dimorphism of the mandible remains relatively
rare in the literature. The few existing studies attempted to
study the sexual dimorphism of the mandible using classical metric
measurements and revealed a sex identification accuracy ranging
from 75 percent to 84 percent. At the present time, none of them
takes into account the complete shape of the mandible with regard
to the differentiation of sex.
The aim of the present study
was to examine the sexual dimorphism of the mandible from the
quantification of its shape using new developments in the elliptic
Fourier method. The sample consisted of a series of 138 lateral
views of toothed mandibles (77 males, 61 females) from individuals
of known sex aged 20 and older. The outline of the mandible was
automatically extracted by image analysis procedures and characterized
by an ordered series of harmonics. Each harmonic was described
by four new parameters termed elliptic descriptors. A characterization
of the shape of the mandible was possible with great precision
using elliptical Fourier analysis. The study of the shape alone
indicated that the average accuracy of sex determination was
86.44 percent. The study of both size and shape revealed that
the average accuracy of sex determination was 95.24 percent.
The superiority of the present
results compared to those obtained by previous studies can be
explained by the fact that conventional morphometric methods
based on linear measurements provide only partial shape information
of the mandibular outline. From the study of the morphological
contributions of the elliptical descriptors, the present analysis
revealed that sex differences could be explained by both size
and shape differences in the mandible, with differences in shape
focusing principally on the ramus, the condyle, and the robustness
of the mandibular body. The present method, which relies on elliptical
descriptors, allows a precise characterization of the sexual
dimorphism of the mandible for the first time and should constitute
an interesting approach for an accurate sexing of fragmented
skeletal material.
Computer
Techniques for Comparing Antemortem and Postmortem Dental Radiographs
Using
Digitized and Digital Images
D. R. Senn, P.
Brumit, M. White, and M. E. Alder
Center for Education and Research in Forensics
University of Texas Health Science Center
San Antonio, Texas
Dentists are taught from
the beginning of their training to recognize anatomical, pathological,
and restorative features in dental radiographs. This skill, when
cultivated over years, helps forensic dentists to make comparisons
of features in dental radiographs to assist in determining identities.
Computer techniques allow direct visual comparison by overlaying
one image on another, decreasing the necessity for subjective
judgments and enhancing scientific objectivity. These techniques
also facilitate demonstration to nondentists in an "easy-to-see"
manner and may be useful in trial settings to demonstrate identifications
to triers of fact. This presentation demonstrates two objectively
reproducible computer techniques that facilitate direct comparisons
between antemortem and postmortem radiographs.
Antemortem radiographs are currently most often received as films.
With the rapid growth of the use of digital radiography in dental
offices, the day may come when most antemortem radiographic information
will be digital. Comparisons in which the only antemortem radiographic
information available was in the form of digitized images received
by E-mail have already been made. The advantages of digital versus
film radiography have already been documented in publications,
and in forensic examinations these advantages are substantial.
Digital radiographs were
acquired using a Schick CDR digital dental unit with a size 2
sensor. Digitized film images were acquired from standard dental
radiographic films using an Epson Expression 636 flatbed scanner
with transparency scanner. Digital or digitized film antemortem
and postmortem radiographs were opened in Adobe Photoshop 5.0
using a Dell Dimension XPS R400 computer with a 400-megahertz
Pentium II processor. Using the Twain acquire feature in Adobe
Photoshop and adjusting the scanning resolution to match that
of the digital images, films were imported. Using landmarks in
restorations or anatomical features, the measure tool, and commands
from the toolbar, it was possible to assure that the features
to be compared in both images were compatible in size.
Using the Image>Adjust
commands and the Magic Wand tool, individual restorations in
the postmortem image were depicted as either solid volume or
hollow volume images. These images were transferred to the antemortem
image. Using the Edit>Transform>Rotate commands and the
Move tool, the postmortem image was aligned in the same orientation
as the antemortem and the direct comparison accomplished.
The transparency overlay
comparison technique allows the overlay of transparent images
of postmortem radiographs over nontransparent antemortem images.
The transparency factor can be adjusted to allow a fade-in, fade-out
comparison, and the transparent image can be moved onto or away
from the underlying antemortem image. This presentation demonstrates
both methods from start to finish and handouts supply step-by-step
instructions.
As in earlier nondigital
methods, exposing the postmortem radiographs in the same or similar
orientations used in the antemortem is essential. Cases with
metal restorations are best suited to the hollow volume technique.
The transparency overlay method works well in cases with or without
restorations. Both methods seem complicated when described but
become intuitive when practiced. Postmortem radiographs made
on "John Doe" cases may not be suitable for these techniques
if subsequently acquired antemortem radiographs were not exposed
in the same orientations.
Direct computer comparison
of antemortem and postmortem digital or digitized radiographs
allows for direct and objective comparison instead of indirect
or side-by-side subjective comparison. These techniques allow
the investigator to illustrate more scientifically reproducible
comparisons. The techniques are used as teaching techniques for
postdoctoral forensic dentistry students and facilitate dental
identification demonstrations to medical examiners and coroners.
They may be useful tools in the courtroom to illustrate identifications
to judges and juries or help to verify identity in disputed identity
cases.
Back to the index
Significance
of Hereditary Factors in
Forensic Ear Identification
S. A. Sholl and
P. Vanezis
University of Glasgow
Glasgow, Scotland
There has been relatively
little speculation as to the potential of ears as a means of
identification, and this possibly is due to the fact that there
are so many other ways to identify an individual (Pertson 1987;
Moenssens et al. 1995; Tilley and Ford 1996). Several attempts,
notably by Alphonse Bertillon in 1862 and Alfred Iannarelli in
the 1940s (Iannarelli 1964 and 1989), have been made to establish
a classification system for the ear with varying success. Generally
speaking, criteria are prioritized by sex and race, followed
by measurements of the dimensions of the ear and the relationship
between various anatomical and anthropometric landmarks.
A study was undertaken to
ascertain whether there is any significant association between
ear characteristics in same-sex or opposite-sex members of the
same family. Two-dimensional digital images of left and right
ears are used to compare the configurations of four preselected
anatomical points: the intertragic notch, the tragus, the antitragus,
and the malchus. The malchus refers to the point on a 2D image
of the ear where the curve of the antihelix intersects with the
curve of the helix root. It has been named "malchus"
after the servant mentioned in the Gospel of John whose ear Peter
cut off (John 18:10). A method was devised to standardize the
digital images to the extent that any differences in the angles
at which they are taken have no influence on the configuration
being studied. Anatomical points are identified and analyzed
using software designed by the University of Glasgow.
Preliminary analysis using
this ear configuration indicates a physiological relationship
between female members of the same family, but it indicates no
relationship between male members of the same family or between
male and female members.
References
Iannarelli, A. V. Iannarelli
System of Ear Identification. Foundation, New York, 1964.
Iannarelli, A. V. Forensic
Identification Series: Ear Identification. Paramont, California,
1989, p. 5.
Moenssens, A. A., Starrs,
J. E., Henderson, C. E., and Inbau, F. E. Scientific Evidence
in Criminal Cases (4th ed.). Foundation, New York, 1995,
Chapter 9.
Pertson, W. J. Ear, lip and
nose prints: Another means of identification, RCMP Gazette
(1987) 49(9):7–15.
Tilley, N. and Ford, A. Forensic
science and crime investigation. In: Crime Detection and Prevention
Series Paper 73. Home Office, London, 1996.
Do Resemblance
Ratings Measure a
Facial Approximation's Accuracy?
C. N. Stephan
Department of Anatomical Sciences
University of Adelaide
Adelaide, Australia
Facial approximation is a
method used to build a deceased person's face from his or her
skull to indicate their facial appearance before death. In forensic
science, facial approximation is used to promote recognition
of a deceased person in an attempt to generate leads that may
aid the process of identifying skeletal remains.
Because forensic facial approximation
is used to promote recognition, an accurate forensic facial approximation
should be easily recognized as the person to whom the skull belonged—the
target individual. However, attempts to assess the accuracy of
forensic facial approximations have commonly been made by resemblance
ratings of the similarity between a facial approximation and
the corresponding target individual.
This study tests the validity
of using such resemblance ratings to assess the accuracy of forensic
facial approximation. Results of the study indicate that there
is no statistically significant difference between resemblance
ratings of facial approximations to target individuals and resemblance
ratings of facial approximations to individuals incorrectly identified
as target individuals.
It is concluded that a resemblance
rating of a facial approximation to an individual does not indicate
the facial approximation's accuracy because a nontarget individual
may receive a resemblance rating equal to or greater than the
target individual.
Digital
3D Reconstruction of Skulls From
Fragments Using Streifenlichttopometrie (SLT) and a Special DNA
Method
J. Subke, M. Zeller,
H. D. Wehner, and H. Wolf
Institute of Legal Medicine
University of Tuebingen
Tuebingen, Germany
This project aims to develop
a method of 3D reconstruction of skulls from fragmented skeletal
remains using Streifenlichttopometrie (SLT) as a digital high-resolution
3D documentation method and a special DNA method applicable for
use on bones up to Neolithic age for fragment differentiation.
In cases involving more than
one victim, the fragmented skeletal remains are first differentiated
by the Zeller method for the extraction of DNA from skeletal
material up to Neolithic age. Isolated and concentrated DNA can
be submitted to the PCR of nuclear STR-loci and of the mitochondrial
D-loop sequence. Through STRs and mtDNA analysis, the skeletal
remains are classified and a possible kinship can be characterized.
In the second step of the
reconstruction, the classified fragments of the skull are digitally
documented in 3D by Streifenlichttopometrie (SLT), a method introduced
by Subke in 1998 as a new 3D photorealistic color documentation
for forensic medicine. SLT is an adaptable, optical 3D measurement
system, which allows the fast (1000,000 point/sec.), high-resolution(<
1 mm) measurement of surfaces and includes the natural color.
In the third step the skull
is digitally restored from the fragments documented in 3D. With
the help of an efficient algorithm of the visualization software,
the exact matching of neighboring fragments is possible. A reference
skull with anatomical landmarks is used to support the exact
positioning of the fragments. The reconstruction of missing fragments
is achieved by means of surface interpolation, the symmetrical
properties of the skull, and a skull database in order to complete
the reconstruction.
The application of SLT provides
the following advantages to digital 3D reconstructions:
- Fast 3D measurement,
- Submillimeter resolution,
and
- Storing of geometry and
color.
In combination with the Zeller
method of DNA extraction, which allows the differentiation of
bones up to Neolithic age, the SLT method is not only effective
for the identification of recent cases, but also for cases of
anthropological and archaeological interest.
Back
to the index
Effect
of Various Facial Heights in an
Edentulous Skull With Special Reference to
Police Artist Reproduction
M. Taister and
J. A. DiZinno
Federal Bureau of Investigation
Washington, DC
H. Borrman and
G. E. Carlsson
Göteborg University
Göteborg, Sweden
When a skull from a deceased,
unknown individual is found by the police, the teeth are usually
present in the jaws, which facilitates identification. For a
skull of an edentulous subject, facial reproduction is much more
difficult because it is not possible to determine the facial
height. This issue has received little attention in the forensic
literature. Facial height is closely related to the vertical
dimension of occlusion (the height of the bite when the teeth
are biting together). The aim of this experiment is to illustrate
the effect of variation in facial height on a police artist's
facial reproduction of an edentulous skull.
The true facial height values
for any edentulous person are unknown. For an edentulous skull,
three sets of occlusal rims (devices used for the determination
of vertical and horizontal jaw relations in the fabrication of
complete dentures) with different vertical dimensions were constructed
in a dental laboratory. These rims produced three different facial
heights on which the police artist based the facial reproduction.
One set provided a facial height that was determined according
to average dental and facial measurements and related to the
skull dimensions of this case. The other two sets of rims were
designed to establish one lower and one higher facial height
than the first with an assumed average dimension.
The three reproductions will
be demonstrated and discussed with regard to the effect of varying
vertical dimension of occlusion on the police artist's facial
reconstruction of an edentulous person.
Gross
Morphological and Visual Examination Versus
DNA Technology: Who Do You Trust?
K. T. Taylor
Facial Images
Austin, Texas
D. M. Glassman
Southwest Texas State University
San Marcos, Texas
This case study examines
the issue of placing total trust in an established scientific
methodology even though gross morphological and visual assessment
indicate contrary findings.
In August 1997, forensic
artist Karen Taylor was asked by the San Antonio, Texas, Police
Department to prepare 2D facial reconstruction drawings from
a skull found in the backyard of a San Antonio residence. Taylor
was told that the wife of the man who lived at the residence
had been missing for several months but had been ruled out as
a match to the skull by DNA analysis.
In addition to the skull,
mandible, and fragmentary postcranial elements, a clump of human
hair was recovered at the scene. Preliminary examination of the
compressed mass indicated that it was composed of diverse hairs
of various lengths, colors, and textures. Lacking reliable hair
information, the reconstructions were prepared with an intentionally
generic hairstyle and color to allow for viewer interpretation.
Taylor developed both frontal and lateral projections of approximate
facial appearance in life with some input from skeletal biologist
Dr. Gentry Steele of Texas A&M University, who was involved
in the recovery at the scene. The drawings were distributed to
the news media in late August, but no responses resulted in the
identification of the remains.
In September 1997, forensic
anthropologist David M. Glassman was asked to examine the same
skeletal material found at the San Antonio residence. The condition
of the skull was excellent and complete except for a dissected
region of the occipital and two teeth, which were extracted for
DNA analyses. The postcranial material was comprised of several
hundred highly fragmentary pieces. The fragmentation was determined
to be the result of perimortem sharp and crushing trauma over
all areas from the neck to the feet.
Osteologic analysis of the
cranium and mandible revealed a female adult of European ancestry.
The postcranial fragments were sorted by bone element wherever
possible. All identifiable fragments were compared for duplication
to assess the MNI statistic. No instances of duplication were
observed. The fragments were relatively consistent in age and
sex morphology, resulting in a conclusion that the remains represented
a single individual. Portions of three cervical vertebrae including
the atlas, axis, and C3 were available to match with each other
and with the occipital condyles of the cranium. Consistency of
articulation was found. The osteologic exam concluded that there
was no indication that the remains represented more than one
individual.
In November 1997, Taylor
viewed a segment of the television program, Unsolved Mysteries,
which profiled the San Antonio case and included a photograph
of the missing wife. Taylor, who was unaware of Glassman's findings
and had not previously seen photographs of the wife, was startled
by the morphological resemblance of the wife to the reconstructions.
She inquired whether the missing woman possibly had a sister.
Upon learning that she did not, Taylor did rudimentary overlay
comparisons of the skull with photographs of the missing woman.
Two different facial photographs indicated a disturbingly favorable
but unscientific comparison, in light of the DNA findings.
The initial DNA testing of
the skull, teeth, and postcranial samples indicated the possibility
of three or more individuals, with the DNA of the wife reportedly
found in the fragments but not in the skull. This led to a prolonged
investigation focused on discovering the identity of the additional
victims. Ultimately, the skull and the fragmentary remains were
retested by the Armed Forces Institute of Pathology and proven
to be those of the missing wife.
Anatomical
Facial Sculpting With Clay and Computers:
A Case Report—Triumph for DNA
R. G. Taylor and
J. G. Clement
School of Dental Science, University of Melbourne
Melbourne, Australia
The discovery of skeletonized
or decomposed human remains creates major problems for investigators
attempting to identify a victim. Often there are no clues to
the identity of the deceased, and despite thorough investigations
by the police, the remains are not claimed. When these traditional
methods fail, an anatomical 3D facial approximation of the deceased
may be attempted. A thorough anthropological examination is carried
out to estimate the sex, age, and race of the unknown individual
using skeletal and dental features. If the facial skeleton is
damaged or incomplete, a preliminary reconstruction of the bony
skeleton will be required. The dentition and/or dentures (or
lack of them in this case) should be closely examined, as they
can provide valuable clues to the articulation of the mandible
in the maxillary fossae. It is also possible to note loss of
vertical height from the face caused by excessive wear of the
occlusal surfaces. Bone loss from the maxillary and mandibular
ridges, abnormal posturing of the mandible, and lack of soft
tissue support of the lips may occur, especially in the wearers
of old dentures. Some of the most prominent features of the face
are reliably inferred from the skeleton when sculpting, but others
are not. The tip of the nose, the shape of the eyebrows, and
the size and shape of the lips and ears are difficult to deduce.
Any manual alteration to these features is at best a matter of
trial and error, not to mention time-consuming. Enhancement through
use of a computer and its associated software can easily overcome
this problem. Stored images with slight variations allow comparison
without alteration to the original. The final result is a humanized
image that can be easily manipulated to create alternate likenesses,
such as an unshaven or bearded face.
A
Disaster Victim Identification Training Kit for
Odontologists and Scene Investigators
R. G. Taylor,
P. J. G. Craig, and J. G. Clement
University of Melbourne, Australia
Melbourne, Australia
J. Ceddia
Monash University, Australia
Melbourne, Australia
V. Winship
Victorian Institute of Forensic Medicine
Melbourne, Australia
As part of a program for
increased preparedness to combat and mitigate the effects of
mass disaster on the Australian community, the inaugural National
Disaster Victim Identification Workshop was hosted in February
1997 by Emergency Management Australia at Mt. Macedon, Victoria.
It was decided during the workshop that each State in Australia
would be responsible for preparing resources sufficient to train
personnel for any type of disaster resulting in the deaths of
up to 50 people.
The forensic odontology group
at the Victorian Institute of Forensic Medicine and School of
Dental Science, University of Melbourne, were provided subsequent
support by the National Institute of Forensic Science (NIFS)
to produce a set of anatomically faithful replicas of skeletal
remains for the training of odontologists and other scene personnel.
The training set was derived
from six original sets of human cranial remains that were carefully
selected to provide a range of ages and ethnic traits. Replicas
of the original remains and modifications of them were made using
a silicone rubber split mold technique. Final replicas were made
in pigmented methyl (colored methacrylate) to provide a realistic
appearance. Partial remains were fashioned from broken pieces
of larger replicas. A variety of dental treatments were performed
on natural teeth substituted in the replicas. Odontograms for
all treatments were constructed and entered into a custom-built
computer software package specifically designed to handle dental
data in large fatality situations.
The software 'DAVID' (Disaster
And Victim IDentification), which includes the replicas and odontograms,
is available on CD-ROM and is also downloadable from the World
Wide Web at the following URL:
http://www.ct.monash.edu.au/~jceddia/david/DAVID.HTM
Radiographs of the replicas
are also supplied.
The entire package is available
for hire from the NIFS by police, emergency services, universities,
and institutes of pathology in all states and territories of
Australia. It is intended for use by local odontologists for
the training of colleagues less experienced in disaster victim
identification and can be used as a large table-top exercise
or in field situations where it can be combined with animal carcasses
and clothing to give greater realism.
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FORENSIC SCIENCE COMMUNICATIONS OCTOBER 2000 VOLUME
2 NUMBER 4 |
