Frontal sinus variation has been used in forensic anthropology to aid in positive identification since the 1920s. As radiographic technology has evolved, so has the quality and quantity of data that radiologists and anthropologists can collect during an individual’s lifetime. This has led to new methodology when comparing antemortem and postmortem radiographic images. The current study aims to look at frontal sinus morphology and dimensional variations on computed tomography (CT) scans, as these are currently the most commonly collected images showing the frontal sinus in its entirety used in clinics in the United States. This study assessed 307 individuals for the morphological analysis and 325 individuals in the dimensional analysis. These individuals represented females and males from Asian, African, European, and Latin American derived groups. It is hypothesized that frontal sinus shape variations will cluster based on assigned sex and population affinities. Similarly, it is hypothesized that dimensional variation, specifically the maximum height, maximum width, and maximum depth, will show statistically significant clustering based on assigned sex and population affinities. The frontal sinus outlines from the CT images were transferred into SHAPE v1.3 in order to run an elliptical Fourier analysis. The dimensional data was measured directly from the images using a MicroDicom viewer. All of the statistical analyses, including Pearson’s Chi-squared and ANOVA tests, were run in R studio. Results indicated that morphologically there is no statistically significant clustering based on assigned sex or population affinity. However, there was statistically significant clustering dimensionally when tested against both assigned sex and population affinity using an ANOVA, indicating that the interactive effects of sexual dimorphism and population affinity influence the dimensions but not the shape of the frontal sinus. These results add to the foundational knowledge that practitioners have surrounding frontal sinus indicating that assigned sex and population affinity have impact on the approximate dimensions of this structure while these variables do not have a statistically significant effect on morphological variation. The results also speak to the idiosyncratic nature of the frontal sinus and bolster confidence using morphological variations as a mean to individuate.

Assigned sex estimation via the greater sciatic notch (GSN) is traditionally performed via physical/visual examination and ordinal scoring; however, this relies on the subjective assessment of morphology for typological classification which may not be reflective of human variation. Three-dimensional (3D) photogrammetry may offer a technologically advanced, low cost, and more objective alternative to assess the complex curvature of anatomical landmarks. This research explores the accuracy of photogrammetry derived 3D models by comparing digital measurements to those obtained from the skeletal elements and to streamline the application of curvature analysis for the estimation of assigned sex from the GSN. This study utilizes the left and right os coxae from 15 skeletal individuals (5 females, 10 males) from the Boston University Chobanian & Avedisian School of Medicine. A Fujifilm X-Pro2 and Fujifilm 35 mm prime lens captured 123 images per element, which were processed in Meshroom by AliceVision® to create a 3D textured mesh. The mesh was exported into Blender for cleanup, scaling, measurement, and curvature analysis. The measurements were between 96.54% and 99.94% consistent across methods and observations. The consistency between digital metric observations increased by an average of 0.07% when compared to the consistency of the dry bone measurements. Additionally, curvature analysis of the GSN correctly estimated the assigned sex of all os coxae in the sample. This study demonstrates that photogrammetry is an accurate and reliable method for the digitization of remains that enables analytical techniques to better capture skeletal variation compared to traditional methods.