Computerized x-ray tomography of fossil hominid skulls

X-ray Imaging Investigation on the Gilding Technique of an Ancient Egyptian Taweret Wooden Statuette

Diagnostic physical methods are increasingly applied to Cultural Heritage both for scientific investigations and conservation purposes. In particular, the X-ray imaging techniques of computed tomography (CT) and digital radiography (DR) are non-destructive investigation methods to study an object, being able to give information on its inner structure. In this paper, we present the results of the X-ray imaging study on an ancient Egyptian statuette (Late Period 722–30 BCE) belonging to the collection of Museo Egizio in Torino and representing an Egyptian goddess called Taweret, carved on wood and gilded with some colored details. Since few specific studies have been focused on materials and techniques used in Ancient Egypt for gilding, a detailed investigation was started in order to verify the technical features of the decoration in this sculpture. Specifically, DR and CT analyses have been performed at the Centro Conservazione e Restauro “La Venaria Reale” (CCR), with a new high resolution flat-panel detector, that allowed us to perform tomographic analysis reaching a final resolution better than the one achievable with the previous apparatus operating in the CCR.

DiceCT applied to fossilized hard tissues: A preliminary case study using a miocene bird

Iodine-based contrasting agents for computed tomography (CT) have been used for decades in medicine. Agents like Lugol's iodine enhance the contrasts between soft tissues and mineralized (skeletal) tissues. Because a recent study on extant avian heads showed that iodine-ethanol (I₂ E) is a better contrast enhancer overall than the standard Lugol's iodine, here, we tested if I₂ E could also enhance the CT contrasts of two fossilized skeletal tissues: bone and calcified cartilage. For this, we used a partial ankle joint from an extinct pheasant from the Late Miocene of Northwest China (Linxia Basin). The pre-staining CT scans showed no microstructural details of the sample. After being immersed into a solution of 1% I₂ E for 8 days and scanned a second time, the contrasts were drastically enhanced between the mineralized tissues (bony trabeculae and calcified cartilage) and the sediments and minerals inside vascular spaces. After three other staining-scanning cycles in 2%, 3%, and 6% I₂ E solutions, the best contrasts were obtained after immersion in 6% I₂ E for 7 days. Energy Dispersive Spectroscopy showed that iodine was preferentially absorbed by the mineralized tissues and the minerals in the vascular spaces, but not by the sediments. This method not only effectively increased the contrasts of two different fossilized skeletal tissues, it was also non-destructive and reversible because part of the fossil was successfully de-stained after a few days in pure ethanol. These preliminary results indicate that iodine-ethanol has the potential to be used widely in vertebrate paleontology to improve CT imaging of fossilized tissues.

MORPHOMUSEUM: AN ONLINE PLATFORM FOR PUBLICATION AND STORAGE OF VIRTUAL SPECIMENS

Since the early 1990s, methods for the acquisition of three-dimensional (3-D) data and computer-assisted techniques for the visualization of such data have grown increasingly popular among biologists, paleontologists, and paleoanthropologists. However, thus far no standardized repository for complex virtual models based on 3-D digital data of specimens has emerged, whereas the need for researchers to provide access to 3-D models of specimens as well as the pressure imposed on authors by scientific journals to make original 3-D morphological data publicly available have increased. MorphoMuseuM (M3) aims to fill this gap. M3 is both a peer-reviewed scientific journal (M3 Journal) and a virtual specimen repository (M3 Repository). All scientific articles and their associated 3-D models deposited in M3 go through a formal review process. Each published model is given a DOI and a unique identifier code, which should be cited by researchers using this model in their scientific publications. In this paper, we describe the place of M3 among other online repositories for 3-D data, and explain how the growing community of biologists working with 3-D data can benefit from using M3.

Computed tomography based forensic gender determination by measuring the size and volume of the maxillary sinuses

PURPOSE

Identification of human body or remains after death is a forensic procedure, which is difficult to perform and is mandatory by law and in compliance with social norms. Sexing the recovered human remains is an integral part of the identification process. Maxillary sinus can be used for gender determination as it remains intact even when the skull and other bones may be badly damaged in casualties where the body is incinerated. Computed tomography (CT) provides an excellent method for examining maxillary sinuses.

MATERIALS AND METHODS

CT images were used to measure the mediolateral, superoinferior, and anteroposterior dimensions and the volume of the maxillary sinuses in 30 patients (15 males and 15 females) to investigate whether these parameters could be used to determine the gender of an individual for forensic identification. The t-test for independent samples was used to compare these values in males and females and the data were subjected to discriminative analysis using SPSS software.

RESULTS

Our method was able to predict the gender with an accuracy of 80.0% in males and 86.7% in females, with an overall accuracy rate of 83.3%.

CONCLUSION

The accuracy rate in this study was comparable, if not higher than many other methods that have been used to predict the gender of an individual from skeletal remains. The length, width, height, and volume of the maxillary sinuses together with other bones could be used for gender determination with a fair degree of accuracy when the whole skeleton is not available.

A virtual world of paleontology

Computer-aided visualization and analysis of fossils has revolutionized the study of extinct organisms. Novel techniques allow fossils to be characterized in three dimensions and in unprecedented detail. This has enabled paleontologists to gain important insights into their anatomy, development, and preservation. New protocols allow more objective reconstructions of fossil organisms, including soft tissues, from incomplete remains. The resulting digital reconstructions can be used in functional analyses, rigorously testing long-standing hypotheses regarding the paleobiology of extinct organisms. These approaches are transforming our understanding of long-studied fossil groups, and of the narratives of organismal and ecological evolution that have been built upon them.

Evaluation of frontal sinus and skull measurements using spiral CT scanning: an aid in unknown person identification

The present study was undertaken to test a simple system for the identification of unknown bodies using spiral CT images of frontal sinus and other skull measurements among selected Iraqi sample. Ninety patients (45 males and 45 females) with age range from 20 to 49 years were selected in this study. Three features and two groups of measurements of frontal sinus and three skull dimensions were obtained from the CT images. Three basic features were F (presence or absence of frontal sinus), S (septum) and S (scalloping). Measurements selected for the study were frontal sinus width, height and anteroposterior length. In addition to measurements of total width, the distance between the highest points of the two sinuses, the distance between the highest points of each sinus to its maximum lateral limit. Skull measurements included; maximum skull length, prostio-bregmatic height and maximum skull width. All data were subjected to a descriptive and discriminative analysis using the SPSS (Version 17.0). The pre-post comparison (number of discordant items) resulted in 95% accurately predicted perfect match for intra-examiner calibration and 90% accurately predicted perfect match for inter-examiners calibration and the result for one discordant item was 5% for intra-examiner calibration and 10% for inter-examiners calibration. The discriminative analysis showed that the ability of the frontal sinus to identify gender was 76.9%, adding the skull measurements to the frontal sinus measurements gave a higher overall classification accuracy for gender (85.9%). Frontal sinus measurements are valuable method in differentiating gender. Adding skull measurements to the frontal sinus measurements can significantly improve accuracy of gender determination using discriminant analysis. CT based films can provide valuable and precise measurements not only for frontal sinus but even for the whole skull that cannot be approached by other means.

New insights into mid-late Pleistocene fossil hominin paranasal sinus morphology

Mid-late Pleistocene fossil hominins such as Homo neanderthalensis and H. heidelbergensis are often described as having extensively pneumatized crania compared with modern humans. However, the significance of pneumatization in recognizing patterns of phyletic diversification and/or functional specialization has remained controversial. Here, we test the null hypothesis that the paranasal sinuses of fossil and extant humans and great apes can be understood as biological spandrels, i.e., their morphology reflects evolutionary, developmental, and functional constraints imposed onto the surrounding bones. Morphological description of well-preserved mid-late Pleistocene hominin specimens are contrasted with our comparative sample of modern humans and great apes. Results from a geometric morphometric analysis of the correlation between paranasal sinus and cranial dimensions show that the spandrel hypothesis cannot be refuted. However, visualizing specific features of the paranasal sinus system with methods of biomedical imaging and computer graphics reveals new aspects of patterns of growth and development of fossil hominins.

A quantitative method for the evaluation of three-dimensional structure of temporal bone pneumatization

Temporal bone pneumatization has been included in lists of characters used in phylogenetic analyses of human evolution. While studies suggest that the extent of pneumatization has decreased over the course of human evolution, little is known about the processes underlying these changes or their significance. In short, reasons for the observed reduction and the potential reorganization within pneumatized spaces are unknown. Technological limitations have limited previous analyses of pneumatization in extant and fossil species to qualitative observations of the extent of temporal bone pneumatization. In this paper, we introduce a novel application of quantitative methods developed for the study of trabecular bone to the analysis of pneumatized spaces of the temporal bone. This method utilizes high-resolution X-ray computed tomography (HRXCT) images and quantitative software to estimate three-dimensional parameters (bone volume fractions, anisotropy, and trabecular thickness) of bone structure within defined units of pneumatized spaces. We apply this approach in an analysis of temporal bones of diverse but related primate species, Gorilla gorilla, Pan troglodytes, Homo sapiens, and Papio hamadryas anubis, to illustrate the potential of these methods. In demonstrating the utility of these methods, we show that there are interspecific differences in the bone structure of pneumatized spaces, perhaps reflecting changes in the localized growth dynamics, location of muscle attachments, encephalization, or basicranial flexion.

Pleistocene human remains and conservation treatments: the case of a mandible from Atapuerca (Spain)

Research on human evolution depends in many cases on the study of fossil remains that have been treated by conservators. Conservation is a discipline with its own principles and methods. Its goal is not only long-term preservation, but also information recovery and the facilitation of research. Therefore, specialists in conservation propose and carry out the interventions, while research requirements must act as a guide in many steps of the process. In this article, we present an example of a strict conservation methodology applied to a human mandible from the Pleistocene site of Gran Dolina (Sierra de Atapuerca, Spain). An extensive diagnostic examination before the intervention included a computer tomography (CT) scan and stereoscopic light microscopy. This paper describes both the intervention and the mechanical preparation in detail. Finally, the intervention is discussed, as well as general conservation techniques. The compiled details show how this interdisciplinary work allowed retention of both the integrity of the specimen and its information. In conclusion, the development of a suitable method of conservation requires collaboration among all the specialists involved in the study of fossil remains.

Determination of gender by measuring the size of the maxillary sinuses in computerized tomography scans

BACKGROUND

Identification of corpses is a difficult forensic procedure and it is mandated by laws and social rules. Comparison of ante mortem and post-mortem medical records, such as dental documents, plays an important role in the identification of corpses. However, typical identification methods may be inconclusive, especially when certain extreme post-mortem changes have developed. Gender has long been determined from the skull, the pelvis and the long bones with an epiphysis and a metaphysis in unknown skeletons. The aim of this study was to investigate whether the width, the length and the height of the maxillary sinuses could be used for determination of gender.

MATERIALS AND METHODS

The width, the length and the height of the maxillary sinuses were measured in 127 adult patients who were admitted to the Department of Radiology for computed tomography scans of their sinuses. Of 127 patients, 62 (48.8%) were females and 65 (51.2%) were males. The width, the length and the height of the maxillary sinuses were measured in Computerized Tomography scans (Hitachi Radix Turbo computed tomography) when the patients were in prone position without sedation or contrast medium. The data were subjected to a discriminative analysis using the SPSS package program (Version 11.5).

RESULTS

The discriminative analysis showed that the accuracy of maxillary sinus measurements-i.e. the ability of the maxillary sinus size to identify gender-was 69.4% in females and 69.2% in males.

CONCLUSION

Computerized Tomography measurements of maxillary sinuses may be useful to support gender determination in forensic medicine; however, with a relatively low-accuracy rate (less than 70%).

Cranial base morphology and temporal bone pneumatization in Asian Homo erectus

The external morphological features of the temporal bone are used frequently to determine taxonomic affinities of fossils of the genus Homo. Temporal bone pneumatization has been widely studied in great apes and in early hominids. However, this feature is rarely examined in the later hominids, particularly in Asian Homo erectus. We provide a comparative morphological and quantitative analysis of Asian Homo erectus from the sites of Ngandong, Sambungmacan, and Zhoukoudian, and of Neandertals and anatomically modern Homo sapiens in order to discuss causes and modalities of temporal bone pneumatization during hominid evolution. The evolution of temporal bone pneumatization in the genus Homo is more complex than previously described. Indeed, the Zhoukoudian fossils have a unique pattern of temporal bone pneumatization, whereas Ngandong and Sambungmacan fossils, as well as the Neandertals, more closely resemble the modern human pattern. Moreover, these Chinese fossils are characterized by a wide midvault and a relatively narrow occipital bone. Our results support the point of view that cell development does not play an active role in determining cranial base morphology. Instead, pneumatization is related to available space and to temporal bone morphology, and its development is related to correlated morphology and the relative disposition of the bones and cerebral lobes. Because variation in pneumatization is extensive within the same species, the phyletic implications of pneumatization are limited in the taxa considered here.

CT-based description and phyletic evaluation of the archaic human calvarium from Ceprano, Italy

The discovery in 1994, of a fossilized human calvarium near Ceprano, Italy, dated about 800-900 thousand years before present, opened a new page for the study of human evolution in Europe. It extended the continental fossil record over the boundary between Early and Middle Pleistocene for the first time and revealed the cranial morphology of humans that where probably ancestral to both Neanderthals and modern Homo sapiens. A tomographic analysis of the Italian specimen is reported here in order to describe size and shape, vascular traces, and other features of the endocranium, as well as some relevant ectocranial traits (particularly of the frontal region). Our results show that the Ceprano calvarium displays plesiomorphies shared by early Homo taxa, involving a general archaic phenotype. At the same time, the presence of some derived features suggests a phylogenetic relationship with the populations referred to the subsequent polymorphic species H. heidelbergensis. The morphology of the supraorbital structures is different from the double-arched browridge of the African H. ergaster, while its superior shape shows similarities with African Middle Pleistocene specimens (Bodo, Kabwe). In contrast, the relationship between supraorbital torus and frontal squama points to an archaic pattern of the relationship between face and vault, associated to moderately narrow frontal lobes and limited development of the upper parietal areas. Despite a nonderived endocranial shape, the increase of cranial capacity (related to a general endocranial widening) and the probable absence of a clear occipital projection also suggest an evolutionary independence from the Asian H. erectus lineage. This analysis therefore supports the conclusion that the Ceprano calvarium represents the best available candidate for the ancestral phenotype of the cranial variation observed among Middle Pleistocene fossil samples in Africa and Europe. Nevertheless, a proper taxonomic interpretation of this crucial specimen remains puzzling.

Internal cranial features of the Mojokerto child fossil (East Java, Indonesia)

The island of Java, Indonesia, has produced a remarkable number of fossil hominid remains. One of the earliest specimens was found in Perning and consists of an almost complete calvaria belonging to a juvenile individual, known as the Mojokerto child (Perning I). Using computed tomography, this study details its endocranial features. The specimen is still filled with sediment, but its inner surface is well preserved, and we were able to reconstruct its endocranial features electronically. The Mojokerto endocast is the only cerebral evidence available for such a young Homo erectus individual. We provide an analytical description, make comparisons with endocasts of other fossil hominids and modern humans, and discuss its individual age and taxonomic affinities. The ontogenetic pattern indicated by the Mojokerto child suggests that the growth and development of the Homo erectus brain was different from that of modern humans. The earliest stages of development, as characterized by this individual, correspond to important supero-inferior expansion, and relative rounding of the cerebrum. The following stages differ from that of modern humans by marked antero-posterior flattening of the brain and particularly antero-posterior development of the frontal lobes, resulting in the adult H. erectus morphology.

Virtual study of the endocranial morphology of the matrix-filled cranium from Eliye Springs, Kenya

This paper provides the first endocranial description of the matrix-filled archaic Homo sapiens cranium from Eliye Springs, Kenya. Using CT-based 3D reconstruction, the virtually cleaned endocranial surface allowed for the assessment of more than 30 metrical and nonmetrical features, most of which are considered of phylogenetic importance. The VOXEL-MAN program used was most valuable in describing and analyzing the morphological conditions. Since many of the features have not been widely or virtually studied, a small sample of late Pleistocene/early Holocene skulls from East Africa was similarly analyzed for insight into recent variation. The comparisons between Eliye Springs and the modern African specimens showed that the endocranial morphology of this probably later Middle Pleistocene hominid falls into, or close to, the modern ranges of variation for most features. This study also addresses the problems of variation and phylogenetic significance of many of the features, and highlights the need for basic studies on the variability and relevance of such endocranial traits in human evolution.

Virtual anthropology (VA): a call for glasnost in paleoanthropology

The adventurous scientist, with a hat protecting him from the fierce sun as he travels from one remote place to another, hunting for fossils of our ancestors, has been a part of the romantic imagination associated with anthropological research in the 20th Century. This picture of the paleoanthropologist still retains a grain of truth. Indeed, many new sites were discovered under troublesome conditions in the recent past and have added substantial information about our origins. But on another front, probably less sensational but no less important, are contributions stemming from the analysis of the already discovered fossils. With the latter, a rapid evolution in anthropologic research took place concurrently with advances in computer technology. After ambitious activities by a handful of researchers in some specialized laboratories, a methodologic inventory evolved to extract critical information about fossilized specimens, most of it preserved in the largely inaccessible interior as unrevealed anatomic structures. Many methodologies have become established but, for various reasons, access to both the actual and the digitized fossils is still limited. It is time for more transparency, for a glasnost in paleoanthropology. Herein are presented some answers to the question of how a high-tech approach to anthropology can be integrated into a predominantly conservative field of research, and what are the main challenges for development in the future.

Re-creating ancient hominid virtual endocasts by CT-scanning

Probably the first radiographic study of human fossils, that by D. Gorganovic-Kramberger on Neandertal remains from Krapina, Croatia, was published in 1906, only 11 years after Röntgen announced the discovery of X-rays. Many subsequent studies on fossil hominids used regular clinical diagnostic radiological apparatus, as depicted in Atlas of Radiographs of Early Man by M.F. Skinner and G.H. Sperber (1982). Some specimens such as crania filled with heavily calcified matrix proved intractable. Ordinary radiographs of such specimens usually failed to reveal endocranial structure, as fossilized bone and calcified endocast were approximately equally radio-opaque. Thus, neither endocranial volume nor structural details were detectable. The only invasive method that could have been employed involved mechanical removal of the solid matrix, but this entailed hazards to the cranial vault and the destruction of the natural endocranial cast. In 1983--1984, G.C. Conroy and M. Vannier utilized recent advances in high-resolution computed tomography to produce non-invasive, intracranial capacity measurements of matrix-filled fossil skulls. They tried the method on two fossil mammal skulls filled with hard sandstone matrix (1984, Science 26:456-458), and then successfully applied it to a South African, matrix-filled cranium of the ancient hominid (hominin) species, Australopithecus africanus from Makapansgat (Conroy et al. 1990, Science 247:838-841). Details of the morphology of the endocranial surface of the braincase were revealed, including the pattern of venous sinus drainage in the posterior cranial fossa. A group based in St. Louis, Vienna, Paris, Rome, and Johannesburg has taken such studies further. Beautiful "virtual endocasts" have been produced on a large male specimen of A. africanus from Sterkfontein, South Africa, and the endocranial capacity has been determined (1998). The methods make it possible to re-create "virtual endocasts" of ancient hominids.

Virtual anthropology: the digital evolution in anthropological sciences

The discovery and explanation of differences among organisms is a major concern for evolutionary and systematic biologists. In physical anthropology, the discrimination of taxa and the qualitative and quantitative description of ontogenetic or evolutionary change require, of course, the analysis of morphological features. Since the 1960s, a remarkable amount of fossil material was excavated, some of it still awaiting a detailed first analysis, some of it requiring re-examination by more developed methods. While the fossil record grew continuously, a revolution in anthropological research took place with advances in computer technology in the 1980s: a handful of innovative researchers working in specialized anthropology laboratories or medical departments developed the methodological inventory needed to extract critical information from subjects in vivo and from fossilized remains. A considerable part of this information is preserved in the physically heretofore inaccessible interior of anatomical structures. Virtual Anthropology (VA) is a means of making them visible and measurable. Thus, VA also allows access to 'hidden' landmarks; in addition, the large number of semilandmarks accessible on the form enhances the power of Geometric Morphometrics analysis. Furthermore, the density information in volume data allows manipulations such as segmentation, impossible with the real, physical object. Moreover, metric body measurements generally, and cranial measurements specifically, are also an important source of information for the analysis of the ontogenetic development of the skeletal system, and--last but not least--for clinical use (e.g., operation planning, operation simulation, prosthetics). Thus, there developed a fruitful interdisciplinary cooperation between statistics, medicine, and physical anthropology.

Using diagnostic radiology in human evolutionary studies

This paper reviews the application of medical imaging and associated computer graphics techniques to the study of human evolutionary history, with an emphasis on basic concepts and on the advantages and limitations of each method. Following a short discussion of plain film radiography and pluridirectional tomography, the principles of computed tomography (CT) and magnetic resonance imaging (MRI) and their role in the investigation of extant and fossil morphology are considered in more detail. The second half of the paper deals with techniques of 3-dimensional visualisation based on CT and MRI and with quantitative analysis of digital images.

Investigating human evolutionary history

We rely on fossils for the interpretation of more than 95% of our evolutionary history. Fieldwork resulting in the recovery of fresh fossil evidence is an important component of reconstructing human evolutionary history, but advances can also be made by extracting additional evidence for the existing fossil record, and by improving the methods used to interpret the fossil evidence. This review shows how information from imaging and dental microstructure has contributed to improving our understanding of the hominin fossil record. It also surveys recent advances in the use of the fossil record for phylogenetic inference.

A new reconstruction of the Le Moustier 1 skull and investigation of internal structures using 3-D-muCT data

Using the non-destructive technique of 3-D micro computed tomography (3-D-microCT), we present a new, virtual reconstruction of the Le Moustier 1 Neandertal skull. This new reconstruction corrects defects found in earlier reconstruction attempts by repositioning misaligned cranial fragments, addressing the problem of asymmetry caused by pressure during the fossilization process, and placing the basioccipital in its proper anatomical position. Metric comparisons between Le Moustier 1 and juvenile and adult Neandertals demonstrate that facial height proceeded at a faster rate of growth than facial prognathism at the beginning of the adolescent period. They also confirm the anterior placement of the basioccipital. A compound painted to match the colour of the fossilized bone was used in previous reconstruction attempts and the aim of this analysis was to remove the false material to reveal to what extent the fossilized bone was preserved. The areas with the most artificial material and glue include the palate, areas around the mandibular teeth, the left frontal, and parts of the right parietal and temporal bones. The microCT data were also used to examine internal structures of the skull including the frontal sinus and the labyrinth of the inner ear. An investigation of the frontal sinus reveals morphology similar to that found in adult Neandertals, although the structure does not extend to mid-orbit. The dimension of the radius of curvature of the lateral semicircular canal falls within one standard deviation, and the anterior and posterior canals within two standard deviations, of the published Neandertal mean. As in other Neandertals, the posterior semicircular canal is in an inferior position relative to the plane of the lateral canal.

Computed tomographic measurements of the nasal sinuses and frontal bone in mummy-heads artificially deformed in infancy

The purpose of the present study was to ascertain whether artificial skull deformation, carried out during infancy, has an effect on the pneumatization of the frontal and maxillary sinuses and on the osseous structure of the frontal bone. Thus, two normal and 12 artificially deformed adult human skulls (12 males, two females) from the collection of pre-Columbian Peruvian skeletons and mummies in the Institute of Anthropology and Human Genetics (University of Munich) were investigated by computed tomography. These skulls had been excavated from four sites on the Peruvian coast: Las Trancas, Cahuachi. Pacatnamu, and Estaqueria. The volumes of the maxillary sinuses varied from 5.18 mL to 17.19 mL. Those of the frontal sinuses varied from zero to 6.21 mL. The artificial deformation of the skull, which occurred during infancy, had no influence on the size of the maxillary and frontal sinuses. There was also no difference in the average bone thickness of the os frontale; however, artificial deformation in infancy had an influence on the bone structure, resulting in a tremendous rarefication of the diploe of the frontal bones. Based on these findings we conclude that the various types of skull deformation instituted in infancy seem to exert no inhibitory effect on the pneumatization of either the frontal or maxillary sinuses.

A comparative study of stereolithographically modelled skulls of Petralona and Broken Hill: implications for future studies of middle Pleistocene hominid evolution

Computer generated three-dimensional stereolithographic models of middle Pleistocene skulls from Petralona and Broken Hill are described and compared. The anterior cranial fossae of these models are also compared with that of another middle Pleistocene skull, Arago 21. Stereolithographic modelling reproduces not only the outer surfaces of skulls, but also features within the substance of the bones, and details of the internal braincase. The skulls of Petralona and, to a somewhat lesser degree, Broken Hill are extremely pneumatized. Previously undescribed features associated with pneumatization are detailed, along with their possible functional significance, polarity, and potential for understanding hominid cranial variation. Petralona and Broken Hill also exhibit a dramatic suite of cerebral features that is probably related to extensive pneumatization of the skull, namely frontal lobes that are tilted and located behind rather than over the orbits, laterally flared temporal lobes, marked occipital projection, and basal location of the cerebellum. Comparison of the anterior cranial fossae of Petralona, Broken Hill, and Arago 21 suggests that external resemblance of skulls may not always correlate with endocranial similarity. We believe that stereolithographic reconstructions have the potential for helping to resolve difficult questions about the origins of Neanderthal and anatomically modern people.

Quantified comparison of frontal sinus patterns by means of computed tomography

The observation of frontal sinus patterning is a well-established technique of personal identification in forensic anthropology. Variations in size, shape, symmetry, border outline, and the presence and number of septa and cells are compared using antemortem and postmortem radiographs. Traditionally, a standard frontal view is utilized. Computed tomography produces contiguous radiographic images of the cranium at predetermined increments. Multiple comparisons of the sinus configuration can therefore be made at different levels. The use of different 'window' settings (attenuation coefficient ranges) for the production of CT scans is discussed. A scoring system is described for the precise and quantified comparison of frontal sinuses in antemortem to postmortem CT scans. The application of these procedures to actual cases is described.

Structural analysis of the mandible by quantitative computed tomography

The study presents quantitative computed tomography (QCT) as a noninvasive method for analyzing the inner bone structure. Randomly selected mandibles from the osteological collection of the "Drago Perović" Institute of Anatomy, School of Medicine, Zagreb were CT-scanned in five bone areas. Analyzing the densitometry curve in two horizontal levels the relation between the compact and spongy bone and the total amount of bone substance in each area were determined. The smallest bone quantity was found in the area of the neck and angle of the mandible, the areas of most frequent bone fractures. The alveolar part of the bone, apart from the area of the angle, was considerably less thick than the base of the mandible. The compact bone was predominant in all CT-scans.

Three-dimensional computed tomography of the mummy Wenuhotep

Computed tomography allows cross-sectional imaging of anthropological as well as clinical subjects. Recently, technical innovations have made three-dimensional reconstruction of these images feasible. We performed two-dimensional and three-dimensional computed tomography of a Late Period Egyptian mummy to reexamine findings seen on previous radiographic studies and to evaluate the usefulness of these techniques in paleopathology. Two-dimensional images provided excellent anatomic detail. There was graphic depiction of the mummification process that corroborated information previously obtained from Egyptological studies. Three-dimensional reconstruction provided images of facial features as if the mummy had been unwrapped. Three-dimensional computed tomography is a useful method of nondestructively evaluating paleopathological remains, and it may yield information not obtainable by any other means.