U.S. Department of Justice

Federal Bureau of Investigation

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 1

The following abstracts of the presentations are ordered alphabetically by authors' last names.

To create an age-determination model for a Turkish population, 84 cases composed of 62 men and 22 women between the ages of 25 and 76 were studied. Cross sections (0.25 mm) of tooth dentin were prepared for appropriate evaluation of transparency. A computer was used for measuring the transparent areas of dentin to minimize error. Photographic images were taken at a scale of 1:1, and the searched images were transferred to a computer. Enlarged images of the cross sections were evaluated in CorelDraw™ and transferred to PhotoPaint™ as black-and-white images. Calculations were made using the Oran™ program to obtain exact results.

In a statistical analysis with the SPSS™ program, the transparent area of the dentin was shown to correlate strongly with age. Age and sex also showed a strong correlation, and there were no significant differences between men and women.

The incisors of the upper and lower jaws were compared with regard to mean values of real and estimated age. Scatter graphs showed a linear but inverse relationship. The increasing transparency of dentin with age and the consequent decrease in the ratio between the transparent area and the root area were expected results. A linear regression analysis was conducted to determine the ratio between age and the transparent area of the dentin. For each tooth, the mean difference between the real and the estimated ages was calculated with a 95 percent confidence interval.

The results of this study demonstrate that the age of unidentified skeletal remains can be determined from the teeth using the dentin transparency method with an error range between 4.5 and 6.5 years of age.

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The evaluation of morphological characteristics can aid in identifying suspects from a police database. Generally, seven facial characteristics—eyes, eyebrows, nose, lips, chin, ears, and the shape of the head—are used for identification purposes.

The aim of this study was to investigate observer variation in the interpretation of facial features of morphological classification as described by Vanezis (1996) with regard to photographs of adult Caucasian males.

Twenty-two dental students were used as observers. Each observer received oral information regarding basic facial morphology and classification. In addition, the main results of the scientific study mentioned above were reviewed. The observers evaluated and registered 25 facial features of one female adult Caucasian by visual inspection.

The results of the study indicated complete agreement among the observers with regard to the morphology of the eyebrow density. Virtually similar findings were found for eyebrow shape (n = 21) and external eyebrow ends (n = 19). Furthermore, approximately 80 percent agreement was noted among the observers in the registration of nasal alae, ear projection, chin projection, facial form, and lower lip thickness. The observers demonstrated the least agreement (approximately 40 percent) with regard to the malars and the nose tip shape. Similarly, variation among the observers in the registration of earlobes, eyebags, philthrum shape, upper lip notch, and chin features was found to be prevalent. The overall results indicate a high degree of variation among the observers regarding the perception of different facial features.

This study emphasizes the importance of law enforcement personnel's awareness of possible difficulties in accurately describing facial features and characteristics. In the field of forensic science this necessity is recognized through use of a second opinion to increase the accuracy of the work.

References

Vanezis, P., Lu, D., Cockburn, J., Gonzalez, A., McCombe, G., Trujillo, O., and Vanezis, M. Morphological classification of facial features in adult Caucasian males based on an assessment of photography of 50 subjects, Journal of Forensic Sciences (1996) 41(5):786–791.

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The first dentistry school, the Chirurgie Dentiste in Paris, was founded in the eighteenth century by the Frenchman Pierre Fauchard. His textbook Le Chirurgien Dentiste ou Traité des Dens, published in 1728, is still considered a milestone in the history of dentistry.

In Fauchard's lifetime, tin, gold, and lead were widely used as fillings for the treatment of dental caries. In the modern western world, tin is not used in dental practice. In unidentified corpses bearing metal fillings and in those bodies in which the length of time since death could play a legal role, use of nondestructive energy dispersive radiofluorescent spectrometry (EDXRF) techniques to determine the constituents of these fillings is a feasible option. The discovery of elements that are no longer in use today, such as tin or lead, combined with other methods of dating would allow insight into deaths occurring in earlier centuries.

Prince Wilhelm Heinrich von Nassau Saarbruecken lived in the southwestern area of Germany. He died in 1768 as a result of a stroke and was buried in the palace church in Saarbruecken.

Recently the body was exhumed and examined. Several teeth, including Tooth 26 on the buccal side, were filled with a silvery matte substance macroscopically resembling amalgam. Tooth 26 was extracted for further investigation. Rastelectronmicroscopy of the buccal side revealed that there was a gap of 2–3 mm between the tooth and filling. Using EDXRF, the filling was determined to be composed of approximately 96 percent tin.

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The difficulties in identifying a subject from photographs are due largely to the poor quality of the photographs and are increased by distortion in the edge area. An additional problem arises when taking multiple repeat photographs, especially when the subject is uncooperative. Even under perfect conditions there are many practically unavoidable problems when preparing photographs of the suspect.

The following question has been raised within the framework of a series of tests: What effect do choice of camera, distance of the subject from the camera, and the exact 3D spatial position of the head have on the preparation of photographs?

The following conclusions can be drawn from the results of testing:

• No significant distortion occurs when the distances between the object and the test person are 1.5 mm or greater using objectives larger than 70 mm.
  
  
• Edge distortions in wide-angle photographs have an insignificant effect on small sections of the photograph.
  
  
• In preparing photographs, exact estimation of the spatial position of the head is difficult.
  
  
• Small differences between the spatial head position at the scene of the crime and in new photographic takes are of little significance in the descriptive comparison of morphological characteristics.
  
  
• Depending on the spatial angle, small differences in head position when evaluating metric size relationships can either play an important role or be of virtually no importance.
  
  
• Using a computer-aided comparison of the head, contour lines in one photograph can be compared to those in a second, even with an axis deviation of approximately 180 degrees.
  
  
• Expert advice concerning morphological characteristics using a "find edges" filter should only be used when the spatial head position in the photographs is identical.
  
  

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Photographing a suspect in order to morphologically compare a culprit's facial characteristics can lead to considerable difficulties. Some disadvantages to this method, such as edge distortions due to the camera objective and small distances between the subject and the object, can be eliminated through compensations or avoidance.

Differences in the spatial position of the head are much more difficult to approximate. In particular, small differences in the spatial head position are rarely avoidable when a suspect is uncooperative. As a result, direct metric comparison of individual characteristics can be difficult or even impossible. This study addresses the question of whether or not a 3D laser-scanning representation of a suspect's head is suitable for reducing or removing this source of error in morphological comparisons.

Using the 3D laser scanner camera Minolta VI 700 (Minolta Europe GmbH, Ahrensburg, Germany) and the program Vivid™, two or more photographs were taken of a test person.

The resulting 3D image of the test person's head was freely rotatable on the monitor in all three axes. Subsequently, this image was compared with that of the culprit on the monitor. By means of rotation, the 3D image of the suspect could be adjusted to match, almost exactly, the culprit's head position.

The following initial conclusions can be made from the test results:

• The development of a 3D image is adequate for an expert opinion.
  
  
• The 3D laser scanner image can be placed directly on the monitor in order to compare morphological characteristics with those of the culprit's photograph.
  
  
• Deviation from the axes of the position of the head can be corrected in a short time using a computer of adequate performance.
  
  
• Metric comparisons of individual characteristics can be subsequently performed.
  
  
• The results can be reproduced.

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Various methods for the identification of skeletal remains are used by law enforcement. Photosuperimposition and facial reconstruction techniques were performed in the unsolved murder case selected for this study. In addition to these techniques, the antemortem craniography was compared to the postmortem craniography. At the conclusion of the study, a successful identification was reached and, as a result, suspects linked to the victim were identified and apprehended.

Current facial approximation ideology often considers facial profile to be a series of discrete anatomical landmarks joined together in some way. Fourier analysis offers opportunities for a more holistic approach to thinking about the nature and relationships of the features of the face. In using Fourier harmonic analysis as a tool in facial approximation, it is hoped that it will be possible to biomathematically infer facial profiles in the saggital plane from given skeletal templates. The success and application of such a technique may add confidence limits to current methods of facial approximation.

It has been established that various facial reconstruction methods can produce substantially different results. Adding to this uncertainty, it has been shown there may be wide variation among each forensic artist's individual interpretations, techniques, and results. How these similarities and differences are to be measured and compared remains problematic, but this is a problem that must be solved if the forensic community and the courts are to have faith in the results of the work of the forensic artist. The ability to measure and compare results between artists will also assist in the establishment of general principles and guidelines for newcomers to the science of forensic art and establish a basis for quality assurance in future developments.

The use of Fourier harmonic analysis as a biometric tool to quantify facial shape and form can reveal differences in the harmonic series descriptive of the face among ethnic groups on a population, but not individual, basis. It also has been found to provide data that can be used to reliably predict certain anatomical and soft tissue morphologies on an individual basis. For comparisons between soft and hard tissue profiles, any Fourier analysis relies heavily upon the establishment of a strictly reproducible experimental protocol. This has proved difficult to develop, largely because of the need to be able to apply any method to the wide variation in anatomy encountered between different subjects. It has been found that the methods developed have needed constant refinement of the definitions used in their protocols and are very sensitive to seemingly small differences in the face, such as lips apart or lips together and the contribution of the teeth to the individual profile. This in turn has imposed the need for great care and consistency of method in the computer generation of facial profiles and their matching skeletal silhouette from the original source material that comprises lateral skull radiographs.

Preliminary results involving comparative Fourier analysis of hard and soft tissue indicate, in most cases, that there is a stronger, positive correlation evident between soft and hard tissue Fourier harmonic profiles of the same individual than in nonmatched hard and soft tissue pairs. Just as important and of more concern, however, positive correlations have been found to be inconclusive in specific instances. Individuals with very similar skeletal profile characteristics but distinctly different soft tissue facial profiles and individuals whose underlying skeletal profile characteristics are not simply reflected in their faces have questioned the potential contribution of Fourier analysis to predictions of facial profile from the silhouette of the underlying skull. This also draws into question the capability of any other predictive strategy to derive the face from the skull using objective criteria.

It is possible that such implications may be related to the capacity of Fourier analysis to provide highly accurate shape description but still present the results in an indiscriminant way or in a format that is currently unintelligible for research purposes. Though tedious in nature, tackling the problem of applying biometric methods to the analysis of facial approximation techniques remains an essential prerequisite for quality assurance and the justification of faith in the fidelity of the results of the artist. The use of Fourier analysis, either independently or in conjunction with other quantitative methods, may or may not be validated as the most appropriate method for the quantification of human facial shape and form. However, the results thus far have shown clearly that the static relationship of the face to the skull may be highly variable, even unpredictable. This should be a cause of serious concern for the forensic artist at the present time.

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The surface of the lips is characterized by patterns of fissures and grooves that are genetically determined and remain substantially unchanged throughout life. As unique to the individual as palatal rugae patterns and fingerprints, they are therefore useful as a form of personal identification. There is, however, no established method of recording lip prints, either experimentally or forensically. This poster demonstrates a simple method for obtaining lip prints of high quality for analysis.

During the visual identification of a human body, morphological characteristics such as tattoos, scars, and fractures are important criteria of examination. These and other morphological characteristics may occur in conjunction or in concert with bone deformation. During a facial reconstruction, cranial characteristics may be associated with morphological characteristics of the individual, facilitating the identification process.

A facial reconstruction of an unidentified skull was conducted using the Desbois–Mallet–Perrot Method. During this reconstruction, it became apparent that the left orbital socket was positioned lower than the right socket; the left eye and its eyelid were reconstructed at a lower position than the right eye to reflect this anatomical characteristic. The discovery of this anomaly and the resultant facial reconstruction enabled the police to identify the body quickly, demonstrating that facial reconstructions can be made more efficient when existing morphological characteristics are highlighted.

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Between 1989 and 1999, 30 facial reconstructions were conducted for identification purposes according to the Desbois–Mallet–Perrot Method, a technique founded on the work of M. M. Glerassimov. Prior to the facial reconstructions, there were no clues to the identities of the deceased persons. Ten identifications were made from the 30 facial reconstructions.

The sequential steps of facial reconstruction are as follows:

• The head is sent by the police to the laboratory.
  
  
• The skull is cleaned.
  
  
• A mold of the skull is made.
  
  
• A model of the skull is made, and the face is reconstructed on this model.
  
  
• The reconstructed faces are returned to the police, who proceed with the identification investigation.

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In forensic science, facial reconstructions are used to stimulate public interest as a last resort when unidentifiable craniofacial remains are recovered. It is a common misconception that facial reconstruction will produce an exact likeness: A resemblance is the best that can be achieved. Variables such as obesity, age, ethnicity, and sex of the individual can ultimately be estimated only from the skeleton. Any individual skull could, in principle, generate a multiplicity of facial reconstructions, all being equally valid outcomes.

Research at the University of Sheffield is aimed at developing a computer system for facial reconstruction that will be accurate, rapid, repeatable, accessible, and flexible. Average tissue-depth measurements collected from a small number of landmark sites on the face are being eliminated in favor of volume data collection from magnetic resonance imaging (MRI) equipment. Virtual reality modeling language (VRML) and the Internet are being used to increase the versatility and accessibility of facial reconstructions.

Research on data collection from the MRI and prototype VRML interpolation models simulating obesity, aging, and ethnicity is described. Some strengths and weaknesses of the models and the potential for application of these models in forensic science and human rights abuse investigations are discussed.

References

Evison, M. P. and Green, M. A. Presenting three-dimensional forensic facial simulations on the Internet using VMRL, Journal of Forensic Sciences (1999) 44:1216–1220.

Green, M. A. and Evison, M. P. Interpolating between computerised three-dimensional forensic facial simulations, Journal of Forensic Sciences (1999) 44:1221–1225.

Tyrrell, A. J., Evison, M. P., Chamberlain, A. T., and Green, M. A. Forensic three-dimensional facial reconstruction: Historical review and contemporary developments, Journal of Forensic Sciences (1997) 42:653–661.

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Skeletal remains cases received at the FBI Laboratory with the request for anthropological examinations often include a request for a facial reproduction. These examinations are conducted by a team consisting of an anthropologist from the Smithsonian Institution, artists in the Investigative and Prosecutive Graphic Unit of the FBI Laboratory, and an anthropologist from the Trace Evidence Unit of the FBI Laboratory.

A variety of examinations can be conducted on skeletal remains and associated collected evidence, which can add a tremendous amount of information to the case. X-rays and DNA analysis of the skeletal remains can aid in identification. Examination of clothing found with the remains can provide information concerning possible sources of such items, as well as information regarding the size of the clothing and any damage present, such as stab holes. Debris found on clothing, weapons, and other associated items can help in identifying possible suspects if the remains are a result of a crime.

In conclusion, the examination of skeletal remains and associated items can provide information beyond the possible identity of the individual. This information can be developed and can aid in determining, among other things, whether the individual represented by the remains died of natural causes as opposed to a criminal act.

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Variability in the shape of the anatomical structures of the skull, especially with regard to the sella turcica, nasal sinuses, mastoid processes, and frontal sinuses, provides the basis for the identification of unknown persons or skeletal remains. The frontal sinuses provide the most accurate method of identification because of the wide shape variations and uniqueness shown in comparative skull radiographs. The conclusions from these identifications can be compared to the individuality of fingerprints.

Seven morphological features of the frontal sinus region (Yoshino et al. 1987)—area size, bilateral asymmetry, unilateral superiority, outline of the left upper board, outline of the right upper board, partial septa, and supraorbital cell—were evaluated during this study. Through this evaluation, every frontal sinus was assigned a seven-digit number representing the quantitative/qualitative values of these anatomical features.

There have been positive identifications of unknown skeletal remains as well as identity exclusions of missing persons in casework conducted by Lithuania's osteological laboratory. This article presents three cases describing the forensic frontal sinus identification of unknown skeletal remains and missing persons.

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Cephalometry, the measurement of the head and face, is a centuries-old science developed by anatomists, anthropologists, artists, maxillofacial surgeons, and others interested in facial esthetics. The subdiscipline of graphic facial analysis (GFA) is the quantitative assessment of the relationships of facial features as determined by specific indices and angles. For example, a nose may be judged to be long with reference to total facial length, the mouth to be wide relative to facial width, the mandible to be prognathic as determined by the mandibulo-facial angle, and so on. An understanding of GFA is essential for composite drawings, forensic facial approximations, and photographic comparisons and seems to be an innate gift among caricaturists.

In this presentation,14 indices and 6 angles for assessing the basic facial relations of the Caucasoid face (more cephalometric data is available for white Europeans and their descendants than for Negroid and Mongoloid populations) will be illustrated. Several cases of photographic comparisons will also be shown to demonstrate the validity of the method.

To clarify whether sex dimorphisms of the petrous portion of the temporal bone can be used for the differentiation of male and female human remains, 410 petrous portions were morphognostically and morphometrically examined. Significant sex dimorphisms were observed. Discriminate functions could be applied to classify approximately two thirds of all petrous portions correctly. Morphognostically, a typical female temporal bone was characterized as gnarled, with more strongly profiled fine structures; the cross section of the porus acusticus internus was round. In contrast, a typical male temporal bone had a less strongly profiled, smooth surface and an oval porus in cross section.

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The diagnosis of gender using the skull is based mainly on morphological characteristics. The differential expression of these characteristics is described in the relevant literature almost identically (Acsádi and Nemeskéri 1970; Bass 1987; Ferembach et al. 1979; Graw et al. 1999; Hoyme and Iscan 1989; Krogman 1962; Novotny et al.1993; Stewart 1948, 1952). These descriptions date back to the eighteenth century and arise from observations of a small series of investigations (Broca 1975; Ecker 1866).

To clarify the significance attributed to the 17 primarily morphological characteristics used in sex differentiation from a current point of view, a collection of 137 forensically recent adult skulls from southwestern Germany was investigated (92 male skulls: 44.6 ± 14.7 years; 45 female skulls: 47.7 ± 19.2 years). A test group (n = 91; 58 male skulls: 43.9 ± 13.0 years; 33 female skulls: 46.5 ± 20.4 years) and a control group (n = 46; 34 male skulls: 45.7 ± 17.3 years; 12 female skulls: 50.9 ± 16.1 years) were chosen by random sampling.

The examination of the morphological characteristics of the test group revealed that, in principle, sex could be differentiated from such characteristics. The variability of the individual morphological characteristics, however, caused them to be of varying degrees of importance in the diagnosis. Only five traits could be attributed with a probability of 70–80 percent and were regarded as sufficiently reliable: the glabella, arcus superciliaris, processus mastoideus, crista supramastoidea, and mandibula (overall impression). By combining these five traits in the analysis, the gender of approximately 91 percent of the skulls could be correctly determined.

References

Acsádi, G. and Nemeskéri, J. History of Human Life Span and Mortality. Akadémiai Kiadó, Budapest,1970.

Bass, W. M. Human Osteology: A Laboratory and Field Manual. Missouri Archaeological Society, Columbia, Missouri, 1987.

Broca, P. Instructions Craniologiques et Craniometriques. Mém d 1 soc d'anthrop de Paris.TII 2.Serie, 1875.

Ecker, A. Ueber eine charakteristische Eigenthümlichkeit in der Form des weiblichen Schadels, Archiv fur Anthropologie (1866) 1:81–88.

Ferembach, D., Schwidetzky, I., and Stloukal, M. Empfehlungen für die Alters-und Geschlechtsdiagnose am Skelett, Homo (1979) 30:1–32.

Graw, M., Czarnetzki, A., and Haffner, H. T. The form of the supraorbital margin as a criterion in identification of sex from the skull: Investigations based on modern human skulls, American Journal of Physical Anthropology (1999) 108:91–96.

Hoyme, L. and Iscan, M. Y. Determination of sex and race: Accuracy and assumptions. In: Reconstruction of Life from the Skeleton. Liss, New York, 1989, pp. 53–93.

Krogman, W. M. The Human Skeleton in Forensic Medicine. Thomas, Springfield, Illinois,1962.

Novotny, V., Iscan, M.Y., and Loth, S. R. Morphologic and osteometric assessment of age, sex, and race from the skull. In: Forensic Analysis of the Skull. Wiley, New York, 1993, pp. 71–88.

Stewart, T. D. Medico-legal aspects of the skeleton: Age, sex, race and stature, American Journal of Physical Anthropology (1948) 6:315–321.

Stewart, T. D. Hrdlicka's Practical Anthropometrie. Wistar, Philadelphia, 1952.

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A popular science program on German television reported on the appearance and fate of human prehistoric and historic mummies and skeletons.

Several plastic facial reconstructions, recently created for various German museums, were presented. The program demonstrated that the reconstructed faces closely resembled those of the historic and prehistoric deceased. Facial reconstructions was done in a blind trial before the camera. A CT-model of the skull of a living person was provided for the facial reconstruction. The results of the experiment are presented.

On an evening in 1957, a 23-year-old Norwegian man was stopped by the police because he had no light on his bike. A few minutes before the young man was stopped, the body of a 16-year-old girl was found in a cellar nearby. On her breast was a deep bite mark. The forensic odontologist determined that the bite marks on the body of the girl matched the bite pattern of the young man. He was sentenced to life in jail but was released after more than 16 years in prison. During this time, he continued to profess his innocence.

Recently, new examinations of the formaldehyde-preserved breast have thrown new light upon the case. It was proven that the young man sentenced for the crime was in actuality not guilty: The bite marks on the breast did not match his bite pattern. The guilty person has not been found.

This case demonstrates the use of an individual's teeth as a form of facial identification.

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FORENSIC SCIENCE COMMUNICATIONS     OCTOBER 2000   VOLUME 2   NUMBER 4