Considerations for Post-processing Parameters in Mixed-Method 3D Analyses: A Mesolithic Mandibular Case Study

The production of three-dimensional (3D) digital meshes of surface and computed tomographic (CT) data has become widespread in morphometric analyses of anthropological and archaeological data. Given that processing methods are not standardized, this leaves questions regarding the comparability of processed and digitally curated 3D datasets. The goal of this study was to identify those processing parameters that result in the most consistent fit between CT-derived meshes and a 3D surface model of the same human mandible. Eight meshes, each using unique thresholding and smoothing parameters, were compared to assess whole-object deviations, deviations along curves, and deviations between specific anatomical features on the surface model when compared with the CT scans using a suite of comparison points. Based on calculated gap distances, the mesh that thresholded at “0” with an applied smoothing technique was found to deviate least from the surface model, although it is not the most biologically accurate. Results have implications for aggregated studies that employ multimodal 3D datasets, and caution is recommended for studies that enlist 3D data from websites and digital repositories, particularly if processing parameters are unknown or derived for studies with different research foci. La producción de mallas digitales tridimensionales (3D) de superficie e información tomográfica computarizada (TC) se ha generalizado en los analisis morfométricos de datos antropológicos y arqueológicos. Dado que los métodos de procesamiento no están estandarizados quedan dudas sobre la comparabilidad de conjuntos de datos 3D procesados y curados digitalmente. El objetivo de este estudio fue identificar los parámetros de procesamiento que tienen la compatibilidad más consistente entre mallas derivadas de TC y un modelo de superficie 3D de la misma mandibula humana. Fueron comparadas ocho mallas cada una con parámetros únicos de umbralización y suavizado, para evaluar las desviaciones de todo el objeto, las desviaciones a lo largo de las curvas y las desviaciones entre características anatómicas específicas en el modelo de superficie, en comparación con cada una de las tomografías computarizadas utilizando un conjunto de puntos de comparación. Con base en las distancias de separación calculadas, aunque no las más precisas desde el punto de vista biológico, se encontró que la malla con umbral en “0” con una técnica de suavizado aplicada se desvía menos de la superficie modelo. Los resultados tienen implicaciones para los estudios agregados que emplean conjuntos de datos 3D multimodales y se recomienda precaución para los estudios que incluyen datos 3D de sitios web y repositorios digitales, especialmente si los parámetros de procesamiento son desconocidos o derivados de estudios con diferentes focos de investigación

Variation in paranasal pneumatisation between Mid-Late Pleistocene hominins

There is considerable variation in mid-late Pleistocene hominin paranasal sinuses, and in some taxa distinctive craniofacial shape has been linked to sinus size. Extreme frontal sinus size has been reported in mid-Pleistocene specimens often classified as Homo heidelbergensis, and Neanderthal sinuses are said to be distinctively large, explaining diagnostic Neanderthal facial shape. Here, the sinuses of fossil hominins attributed to several mid-late Pleistocene taxa were compared to those of recent H. sapiens. The sinuses were investigated to clarify differences in the extent of pneumatisation within this group and the relationship between sinus size and craniofacial variation in hominins from this time period. Frontal and maxillary sinus volumes were measured from CT data, and geometric morphometric methods were used to identify and analyse shape variables associated with sinus volume. Some mid

Ecogeographic Patterns of Maxillary Sinus Variation Among Homo sapiens: Environmental Adaptation or Architectural By-product?

Ecogeographic patterns of modern human craniofacial diversity suggest external nasal structures reflect climatic adaptations for respiratory and thermoregulatory functions. Regarding internal structures, the maxillary sinus supposedly varies as a function of the nasal cavity while not contributing in respiratory function. Owing to conflicting results, this study reinvestigates that claim by evaluating maxillary sinus variation in a larger sample (n=200) spanning 11 ecogeographic regions. The surface-area-to-volume (SA:V) ratio (i.e., relative mucosal area) was collected in addition to sinus volume and linear dimensions. Pearson correlations show nasal cavity breadth and maxillary sinus volume are not significantly correlated, and individuals from cold, versus hot, climates exhibit larger volumes with lower surface-area-to-volume (SA:V) ratios. Individuals from high altitudes display a unique configuration with high SA:V ratios and large maxillary sinus volumes. Analyses of variance largely fail to find significant differences among the 11 samples. However, a canonical variate analysis of nasal and sinus dimensions indicates clear separations between the heat- and cold-adapted populations, as well as among the cold-adapted populations. Specifically, Arctic populations display smaller sinus volumes and lower SA:V ratios. Mantel tests indicate certain sinus dimensions depart from isolation-by-distance models. Results indicate that maxillary sinus form does not simply follow isolation-by-distance models and cannot simply be explained in terms of nasal cavity breadth or craniofacial architecture— suggesting that environmental pressures are directly acting on the sinus. Functional possibilities for the sinus include thermoregulatory functions among Arctic populations and/or nitric oxide production for high-altitude populations. Additional considerations and future lines of research are presented

The Effects of Cranial Orientation on Forensic Frontal Sinus Identification as Assessed by Outline Analyses

The utility of frontal sinuses for personal identification is widely recognized, but potential factors affecting its reliability remain uncertain. Deviations in cranial position between antemortem and postmortem radiographs may affect sinus appearance. This study investigates how slight deviations in orientations affect sinus size and outline shape and potentially impact identification. Frontal sinus models were created from CT scans of 21 individuals and digitally oriented to represent three clinically relevant radiographic views. From each standard view, model orientations were deviated at 5° intervals in horizontal, vertical, and diagonal (e.g., left-up) directions (27 orientations per individual). For each orientation, sinus dimensions were obtained, and outline shape was assessed by elliptical Fourier analyses and principal component (PC) analyses. Wilcoxon sign rank tests indicated that sinus breadth remained relatively stable (p > 0.05), while sinus height was significantly affected with vertical deviations (p < 0.006). Mann–Whitney U tests on Euclidean distances from the PC scores indicated consistently lower intra- versus inter-individual distances (p < 0.05). Two of the three orientations maintained perfect (100%) outline identification matches, while the third had a 98% match rate. Smaller and/or discontinuous sinuses were most problematic, and although match rates are high, practitioners should be aware of possible alterations in sinus variables when conducting frontal sinus identifications

The Effects of Cranial Orientation on Forensic Frontal Sinus Identification as Assessed by Outline Analyses

The utility of frontal sinuses for personal identification is widely recognized, but potential factors affecting its reliability remain uncertain. Deviations in cranial position between antemortem and postmortem radiographs may affect sinus appearance. This study investigates how slight deviations in orientations affect sinus size and outline shape and potentially impact identification. Frontal sinus models were created from CT scans of 21 individuals and digitally oriented to represent three clinically relevant radiographic views. From each standard view, model orientations were deviated at 5° intervals in horizontal, vertical, and diagonal (e.g., left-up) directions (27 orientations per individual). For each orientation, sinus dimensions were obtained, and outline shape was assessed by elliptical Fourier analyses and principal component (PC) analyses. Wilcoxon sign rank tests indicated that sinus breadth remained relatively stable (p > 0.05), while sinus height was significantly affected with vertical deviations (p p < 0.05). Two of the three orientations maintained perfect (100%) outline identification matches, while the third had a 98% match rate. Smaller and/or discontinuous sinuses were most problematic, and although match rates are high, practitioners should be aware of possible alterations in sinus variables when conducting frontal sinus identifications

A preliminary 3D computed tomography study of the human maxillary sinus and nasal cavity

Despite centuries of investigation, the function of the maxillary sinus (MS) and underlying patterns governing its form remain elusive. In this study, we articulate a methodology for collecting volumetric data for the MS and nasal cavity (NC) from computed tomography (CT) scans and report details for a small sample of 39 dried human crania of known ecogeographic provenience useful for assessing variation in MS size and shape. We use scaling analyses to preliminarily test the hypothesis that volumes of the nasal cavity (NCV) and maxillary sinus (MSV) are inversely correlated such that the NC covaries with size of the face, whereas the MS "fills in" the leftover space [proposed by Shea: Am J Phys Anthropol 47 (1977):289-300]. Against expectation, MSV is not significantly correlated with NCV or any cranial size variable. NCV, on the other hand, scales isometrically with facial size. The results of this pilot study suggest that NCV covaries with facial size, but that the MS does not simply fill in the leftover space in the face. The role, if any, of the MSs in midfacial function and architecture remains unclear. Larger sample sizes, additional environmental variables, and assessment of MS and NC shape are necessary to resolve this issue

Frontal sinus ontogeny and covariation with bone structures in a modern human population : base de datos

Fil: Ventrice, Fernando. Laboratorio de Neuroimágenes. Departamento de Imágenes. Instituto de Investigaciones Neurológicas Raúl Carrea. FLENI. Buenos Aires; ArgentinaFil: Sardi, Marina Laura. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Antropología; ArgentinaFil: Joosten, Germán G.. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Antropología; ArgentinaFil: Pandiani, Cynthia D.. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Antropología; ArgentinaFil: Gould, María Mercedes. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Antropología; ArgentinaFil: Anzelmo, Marisol. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Antropología; Argentin