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Virtual anthropology (VA) is based on applying anthropological methods currently used to analyse bones to 3D models of human remains. While great advances have been made in this endeavour in the past decade, several interrogations concerning how reliable these models are and what their proper use should be remain unanswered. In this research, a fundamental assumption of VA has been investigated: if the way we perceive and apply an anthropological method is truly similar when looking at bones macroscopically and through various 3D media. In order to answer, 10 skulls of known age and sex were scanned using a computed tomography (CT) scanner and a 3D surface scanner. Two observers separately applied a defined staging method to eight suture sites on these skulls, first looking at the bone macroscopically, then at the 3D surface scan, and finally on the CT scan. Two rounds of observation were carried out by each observer. Intra- and inter-observer error were evaluated, and two sample t-tests used to evaluate if the different types of medium used yielded significantly different observations. The results show a high degree of inter-observer error, and that data obtained from 3D surface scans differ from macroscopic observation (confidence level 95%, P ≤ 0.05). CT scans, in these settings, yielded results comparable to those obtained through macroscopic observations. These results offer many possibilities for future research, including indications on the kind of anthropological methods and anatomical landmarks that might be reliably transferable to the virtual environment. All current methods used in traditional anthropology should be tested, and if they prove unreliable, new techniques to analyse bones from virtual models should be developed. Large discrepancies between observation on dry bones and computer-generated 3D models (surface scans or CT scans) could lead to the re-evaluation of the suitability of traditional anthropological methods for application on 3D models. This preliminary study evaluates whether macroscopic, 3D surface scans, and CT scans viewings generate different observations. The results indicate that the data are not always coherent across all three media of observation. Explanations include the aspect given to the bone by the 3D software, differences between handling bones in real life versus on a computer, and level of expertise of the observers. [ABSTRACT FROM AUTHOR]

Three-dimensional surface scanning (3DSS) and multi-detector computed tomography (MDCT) are two techniques that are used in legal medicine for digitalizing objects, a body or body parts such as bones. While these techniques are more and more commonly employed, surprisingly little information is known about the quality rendering of digitalized three-dimensional (3D) models provided by each of them. This paper presents findings related to the measurement precision of 3D models obtained through observation of a study case, where a fractured skull reconstructed by an anthropologist was digitalized using both post-mortem imaging methods. Computed tomography (CT) scans were performed using an 8-row MDCT unit with two different slice thicknesses. The variability of 3D CT models superimposition allowed to assess the reproducibility and robustness of this digitalization technique. Furthermore, two 3D surface scans were done using a professional high resolution 3D digitizer. The comparison of 3D CT-scans with 3D surface scans by superimposition demonstrated several regions with significant differences in topology (average difference between +1.45 and -1.22 mm). When comparing the reproducibility between these two digitalizing techniques, it appeared that MDCT 3D models led in general to greater variability for measurement precision between scanned surfaces. Also, the reproducibility was better achieved with the 3D surface digitizer, showing 3D models with fewer and less pronounced differences (from +0.32 to -0.31 mm). These experiments suggest that MDCT provides less reproducible body models than 3D surface scanning. But further studies must be undertaken in order to corroborate this first impression, and possibly explain the reason for these findings.