Investigating the impact of captivity and domestication on limb bone cortical morphology: an experimental approach using a wild boar model.

The lack of bone morphological markers associated with the human control of wild animals has prevented the documentation of incipient animal domestication in archaeology. Here, we assess whether direct environmental changes (i.e. mobility reduction) could immediately affect ontogenetic changes in long bone structure, providing a skeletal marker of early domestication. We relied on a wild boar experimental model, analysing 24 wild-born specimens raised in captivity from 6 months to 2 years old. The shaft cortical thickness of their humerus was measured using a 3D morphometric mapping approach and compared with 23 free-ranging wild boars and 22 pigs from different breeds, taking into account sex, mass and muscle force differences. In wild boars we found that captivity induced an increase in cortical bone volume and muscle force, and a topographic change of cortical thickness associated with muscular expression along a phenotypic trajectory that differed from the divergence induced by selective breeding. These results provide an experimental proof of concept that changes in locomotor behaviour and selective breeding might be inferred from long bones morphology in the fossil and archaeological record. These trends need to be explored in the archaeological record and further studies are required to explore the developmental changes behind these plastic responses.

Structure and composition of the Trinil femora: functional and taxonomic implications.

The original hominin femur (Femur I) and calotte discovered at Trinil, Java by Eugene Dubois in 1891/1892 played a key role in the early history of human paleontology by purportedly demonstrating the contemporaneity of archaic cranial form with modern human erect (bipedal) posture. On this basis, both specimens were subsequently assigned to Pithecanthropus erectus, later transferred to Homo erectus. However, chronological and phylogenetic links between the two have been questioned from the beginning. Four additional hominin partial femora (Femora II-V) from Trinil were subsequently described but have played a relatively minor part in evolutionary scenarios. Here we present the results of a new analysis of structural and density characteristics of the Trinil femora obtained using computed tomography. Trinil Femur I shows none of the characteristics typical of early Homo femora from elsewhere in Asia or Africa, including a relatively long neck, increased mediolateral bending rigidity of the mid-proximal shaft, or a low position of minimum mediolateral breath on the shaft. In contrast, Femora II-V all demonstrate features that are more consistent with this pattern. In addition, material density distributions within the specimens imply more recent and less complete fossilization of Femur I than Femora II-V. Thus, it is very likely that Trinil Femur I derives from a much more recent time period than the calotte, while the less famous and less complete Femora II-V may represent H. erectus at Trinil. The morphological variation within the Trinil femora can be attributed to broader changes in pelvic morphology occurring within the Homo lineage between the Early and late Middle Pleistocene.

Analysis of swallowing after partial frontolateral laryngectomy with epiglottic reconstruction for glottic cancer.

The aim of the study was to evaluate swallowing using a reproducible objective methodology and to seek preoperative factors that could influence swallowing outcomes in patients operated on for partial laryngectomy. Twenty-four patients who underwent partial frontolateral laryngectomy with epiglottic reconstruction for T1bN0 or T2N0 glottic carcinoma between 2008 and 2012 were retrospectively evaluated. Using fiberoptic endoscopic and videofluoroscopic evaluation, early (15 days postoperatively) and late (2 months postoperatively) scores were obtained for all patients to quantify their swallowing skills. Eighty-three percent of patients achieved at least partial oral feeding at time of hospital discharge and 87.5% achieved exclusive oral feeding within 2 months postoperatively. Early score was good or excellent in 50%, average in 4.2% and poor in 41.8%. Regarding late scores, 63% were classified as having a good or excellent late score, 7 patients (29%) were classified as "middle result" because their time to recover was longer (i.e. between 1 and 2 months postoperatively), and two patients had a poor late score. Finally, at last follow-up, only one patient was partially fed by gastrostomy (180 days after surgery). T stage (p = 0.04) was the only factor influencing early swallowing outcomes and length of hospital stay was longer for poor scores than for good late results (p = 0.02). Our findings show good outcomes in terms of postoperative swallowing. Objective assessment of deglutition is essential for a better understanding of the mechanisms of postoperative swallowing disorders and for patient selection.

Morphometric measurements and sexual dimorphism of the piriform aperture in adults.

PURPOSE: The aim of this study was to evaluate the dimensions (maximal width and length), the size and the shape of the PA and their sexual dimorphism. METHODS: Using 3D-CT scan reconstructions and landmarks positioning around the piriform aperture and on the face, a collective of 170 non-pathologic subjects (79 female, 91 male) from Marseille (France) was examined in classical and geometric morphometrics methods. RESULTS: The mean width of the piriform aperture was 24.00 mm in females and 25.32 mm in males, the mean length was 32.54 mm in females and 36.35 mm in males. The difference between males and females was significant, and our data correlates well with the previously data acquired from humans skulls. Facial measurements also showed a statistically significant dimorphism. In morphometric geometrics, the correlation between the centroïd size and PC1 in the shape space was weak, while this correlation was strong in the size and shape space. Visualization of shape differences was achieved on 2D wireframes. CONCLUSION: Shape and size analysis of the piriform aperture showed the existence of a significant sexual dimorphism. These results encourage us to go further with functional and imaging correlations.

Analysis of hyoid bone using 3D geometric morphometrics: an anatomical study and discussion of potential clinical implications.

The aim of this study was to obtain a quantitative anatomical description of the hyoid bone using modern 3D reconstruction tools and to discuss potential applications of the knowledge in clinical practice. The study was conducted on 88 intact hyoid bones taken from cadavers during forensic autopsies (group 1) and on 92 bones from CT scan images of living adult subjects (group 2). Three-dimensional reconstructions were created from CT scan images using Amira 5.3.3® software. An anatomical and anthropological study of hyoid bones was carried out using metric and morphological analyses. Groups 1 and 2 were compared to evaluate the influence of muscle traction on hyoid bone shape. Characteristics of the hyoid bone were highly heterogeneous and were closely linked with the sex, height, and weight of the individuals. Length and width were significantly greater in men than in women (39.08 vs. 32.50 mm, p = 0.033 and 42.29 vs. 38.61 mm, p = 0.003), whereas the angle between the greater horns was larger in females (44.09 vs. 38.78, p = 0.007). There was a significant positive correlation between the height (Pearson coefficient correlation r = 0.533, p = 0.01) and weight (r = 0.497, p = 0.01) of subjects and the length of the hyoid bone. Significant metric differences were shown between group 1 and group 2. This very reproducible methodology is important because it may lead to clinical studies in, e.g., head and neck cancer or sleep apnea. Such studies are ongoing in our research program.

Structural analysis of the Kresna 11 Homo erectus femoral shaft (Sangiran, Java).

The biomechanical characterization of lower limb long bones in the chrono-ecogeographically diverse species Homo erectus is a fundamental step for assessing evolutionary changes in locomotor mode and body shape that occurred within the genus Homo. However, the samples available for the Early and earlier Middle Pleistocene are small and widely scattered in time and space, thus limiting our understanding of the nature and polarity of morphological trends. Compared to the African fossil record, loading histories based on detailed biomechanical assessment of diaphyseal strength in Indonesian H. erectus lower limb long bones have not been assessed. By using a microtomographic record (µCT), we performed a quantitative analysis of the biomechanical properties and structural organization of Kresna 11, a late Early Pleistocene adult H. erectus femoral shaft from the Sangiran Dome, Central Java. Relative to the modern human condition, Kresna 11 shows the predominant mediolateral cortical thickening (hypertrophy) and the distal displacement of the minimum diaphyseal breadth characteristic of early Homo femora, associated nonetheless with relatively modest cortical thickness within the mid-proximal portion. Synthetic functional imaging of the shaft through the planar representation of its inner structure has revealed distal thickening of the medial cortex, a feature previously unreported in H. erectus. The increase in relative mediolateral bending strength observed in Kresna 11 supports the hypothesis that, rather than simply reflecting differences in patterns of locomotor loading, biomechanical properties of the femoral shaft in archaic Homo are strongly influenced by body shape, i.e., variations in pelvic breadth and femoral neck length.

A three-dimensional axis for the study of femoral neck orientation.

A common problem in the quantification of the orientation of the femoral neck is the difficulty to determine its true axis; however, this axis is typically estimated visually only. Moreover, the orientation of the femoral neck is commonly analysed using angles that are dependent on anatomical planes of reference and only quantify the orientation in two dimensions. The purpose of this study is to establish a method to determine the three-dimensional orientation of the femoral neck using a three-dimensional model. An accurate determination of the femoral neck axis requires a reconsideration of the complex architecture of the proximal femur. The morphology of the femoral neck results from both the medial and arcuate trabecular systems, and the asymmetry of the cortical bone. Given these considerations, two alternative models, in addition to the cylindrical one frequently assumed, were tested. The surface geometry of the femoral neck was subsequently used to fit one cylinder, two cylinders and successive cross-sectional ellipses. The model based on successive ellipses provided a significantly smaller average deviation than the two other models (P < 0.001) and reduced the observer-induced measurement error. Comparisons with traditional measurements and analyses on a sample of 91 femora were also performed to assess the validity of the model based on successive ellipses. This study provides a semi-automatic and accurate method for the determination of the functional three-dimensional femoral neck orientation avoiding the use of a reference plane. This innovative method has important implications for future studies that aim to document and understand the change in the orientation of the femoral neck associated with the acquisition of a bipedal gait in humans. Moreover, the precise determination of the three-dimensional orientation has implications in current research involved in developing clinical applications in diagnosis, hip surgery and rehabilitation.

Technical note: Morphometric maps of long bone shafts and dental roots for imaging topographic thickness variation.

Qualitative and quantitative characterization through functional imaging of mineralized tissues is of potential value in the study of the odontoskeletal remains. This technique, widely developed in the medical field, allows the bi-dimensional, planar representation of some local morphometric properties, i.e., topographic thickness variation, of a three-dimensional object, such as a long bone shaft. Nonetheless, the use of morphometric maps is still limited in (paleo)anthropology, and their feasibility has not been adequately tested on fossil specimens. Using high-resolution microtomographic images, here we apply bi-dimensional virtual "unrolling" and synthetic thickness mapping techniques to compare cortical bone topographic variation across the shaft in a modern and a fossil human adult femur (the Magdalenian from Chancelade). We also test, for the first time, the possibility to virtually unroll and assess for dentine thickness variation in modern and fossil (the Neanderthal child from Roc de Marsal) human deciduous tooth roots. The analyses demonstrate the feasibility of using two-dimensional morphometric maps for the synthetic functional imaging and comparative biomechanical interpretation of cortical bone thickness variation in extant and fossil specimens and show the interest of using this technique also for the subtle characterization of root architecture and dentine topography. More specifically, our preliminary results support the use of virtual cartography as a tool for assessing to what extent internal root morphology is capable of responding to loading and directional stresses and strains in a predictable way.