Jana Velemínská

Bone radiodensity is often reduced to global Hounsfield Unit (HU) summaries, although its spatial distribution may contain biologically relevant information. This study introduced a template-based framework for spatial radiodensity mapping of the adult human hyoid and tested whether spatial descriptors capture age- and sex-related variation better than whole-bone HU measures. Clinical head-and-neck CT scans from 300 adults, including 180 females and 120 males, were analyzed. Hyoids were segmented, normalized into a common anatomical template, and divided into 1500 supervoxels for spatial analysis. Scalar HU summaries were compared with PCA-based spatial descriptors, and regional effects were assessed using supervoxel-wise models with false-discovery-rate correction. The registered radiodensity maps showed spatial coherence, with neighboring supervoxels displaying more similar profiles than distant ones. In this cohort, spatial descriptors outperformed mean HU for age prediction, although performance remained limited (R² = 0.255). Sex classification was moderate (ROC AUC = 0.810; balanced accuracy = 0.725). After the spatial features were adjusted for native volume, sex-classification AUC fell to 0.671, and none of the 51 unadjusted regional sex associations survived volume adjustment. Age-related associations involved the hyoid body, the body–greater horn transition, and the proximal-to-mid greater horns. These findings demonstrate spatial coherence in the registered maps but show that the sex-related pattern is strongly size-dependent.

This study investigates the development of facial asymmetry in healthy right-handed adolescents and young adults. Using 3D imaging and analytical methods, it aims to summarize age-related changes in directional asymmetry (DA). The material consisted of four-year semi-longitudinal sample of 46 right-handed participants (24 males), aged 15–20 years. DA was analysed using geometric morphometrics, specifically polygonal mesh analysis and multivariate statistics on IA PC scores, which revealed no significant effect of sex or age group on facial DA. All differences and changes were of localized nature only. These include right-sided protrusion of the lateral forehead, nose, both lips, and chin area; left-sided protrusion of the orbital area. In terms of changes across age groups, in the older categories, the areas of asymmetry on the frontal face tended to shift and expand to the lower portion of the face. Areas on the lateral part of the face showed no significant asymmetries. We conclude that, although no influence of sex and age on global asymmetry was observed, both sexes exhibit a small degree of different localized changes across studied age groups. These partially different trends may point to overall localized manifestation of facial DA or high degree of its inter-individual variability.

The accurate individual identification of skeletal remains is indispensable in forensic contexts. The skull serves as an important source of information about the sex of human skeletal remains, and many different approaches have been published. High method success and reliability are prerequisites for the legal utilisation of results. However, the population specificity of variable sexual dimorphism typically reduce effectiveness. This study presents a verification of an innovative classification model using the exocranial surface across a multi-population sample. This sex estimation method proved to be highly reliable and accurate for Central European populations, achieving high accuracy rates for Czech (96%) and Slovak (92%) samples. The French sample had an accuracy of 90%, demonstrating the method’s effectiveness in Southern European contexts. Prediction using the combined data from these three populations achieved a cross-validation accuracy of 91.74%. When this classifier model was applied to Egyptian crania, the accuracy dropped to 82%, and when applied to crania from a Danish dataset to 80%. The reasons for the failure of the classifier are the smaller degree of sexual dimorphism among Danes, and the more distinct morphological differences in males and females among Egyptians. These lower accuracy rates indicate that the classifier’s reliability diminishes when applied to more diverse and geographically distant populations. The classifier does not work well when applied to a population other than that for which it was developed. The method is robust, and requires further refinement to achieve similar reliability across a broader range of populations.

In this study we tested classification performance of a sex estimation method from the mandible originally developed by Sella-Tunis et al. (2017) on a heterogeneous Israeli population. Mandibular linear dimensions were measured on 60 CT scans derived from the Czech living population. Classification performance of Israeli discriminant functions (DFs-IL) was analyzed in comparison with calculated Czech discriminant functions (DFs-CZ) while different posterior probability thresholds (currently discussed in the forensic literature) were employed. Our results comprehensively illustrate sensitivity of different discriminant functions to population differences in body size and degree of sexual dimorphism. We demonstrate that the error rate may be biased when presented per posterior probability threshold. DF-IL 1 showed least sensitivity to population origin and fulfilled criteria of sufficient classification performance when applied on the Czech sample with a minimum posterior probability threshold of 0.88 reaching overall accuracy ≥ 95%, zero sex bias, and 80% of classified individuals. The last parameter was higher in DF-CZ 1 which was the main difference between those two DFs suggesting relatively low dependance on population origin. As the use of population-specific methods is often prevented by complicated assessment of population origin, DF-IL 1 is a candidate for a sufficiently robust method that could be reliably applied outside the reference sample, and thus, its classification performance deserves further testing on more population samples.

Cluster analyzes of facial models of autistic patients aim to clarify whether it is possible to diagnose autism on the basis of facial features and further to stratify the autism spectrum disorder. We performed a cluster analysis of sets of 3D scans of ASD patients (116) and controls (157) using Euclidean and geodesic distances in order to recapitulate the published results on the Czech population. In the presented work, we show that the major factor determining the clustering structure and consequently also the correlation of resulting clusters with autism severity degree is body mass index corrected for age (BMIFA). After removing the BMIFA effect from the data in two independent ways, both the cluster structure and autism severity correlations disappeared. Despite the fact that the influence of body mass index (BMI) on facial dimensions was studied many times, this is the first time to our knowledge when BMI was incorporated into the faces clustering study and it thereby casts doubt on previous results. We also performed correlation analysis which showed that the only correction used in the existing clustering studies—dividing the facial distance by the average value within the face—is not eliminating correlation between facial distances and BMIFA within the facial cohort.

Objectives: Facial directional asymmetry research, including age-related changes, is crucial for the evaluation of treatment of craniofacial malformations/trauma in orthodontics, facial surgery and forensic sciences. The aim was to describe facial directional asymmetry (DA) in different age categories of adults using 3D methods. According to our hypothesis, facialshape DA(1) depends on sex; (2) differs among age groups; and (3) has wider variability in older age.Material and methods: A cross-sectional sample of healthy Czech adults without craniofacial trauma or anomalies consisted of 300 3D facial models (151 females). The age-range in the study was between 20–80 years. The shape asymmetry of 28 3D landmarks was evaluated using geometric morphometrics and multivariate statistics.Results: The manifestation of DA was similar in both sexes and in each age category; however, there were some statistical differences. In contrast to the ideal symmetrical face, the mean asymmetrical faces tended to create a slightly bent “C” shape of the midline. Therefore, the upper face was rotated slightly clockwise and the lower face counter-clockwise. The right eye was located slightly higher, with the nasal tip and mandibular region tilting to the left. Sex differences in facial DA were significant before the age of 40. DA was more significant in the youngest males than in the oldest, while the women’s DA did not change.Conclusions: The DA patterns were similar in both sexes and in all age categories (a slightly bent C shape of the midline); however, some significant local differences between male age groups were found. A significantly more pronounced asymmetry compared to other age groups was found only in the youngest males from 20 to 40 years. Moreover, significant sexual dimorphism of DA rapidly decreased after middle age, likely caused by the same age-related changes of the face during aging.

Purpose To report atypical anatomical variation of an osseous suprascapular canal, and to elaborate on its clinical significance as a potential anatomical factor that could obscure a direct posterior surgical approach and suprascapular nerve block. Methods Osteological observational study of the scapula with emphasis on the suprascapular space. The pool of investigated sample size was collectively 768 specimens composed of 529 adult dry scapulae (240 paired, 289 un-paired), 54 children dry scapulae, 135 wet scapulae observed during cadaveric dissections, 47 retrospective 3D CT reconstructions, and 3 retrospective full sequence shoulder MRI. The two reported cases came from the 240 (120 skeleton) observed paired scapulae. Furthermore, the osseous suprascapular canal was examined by X-rays and its internal path was exposed by CT sections. A narrative review was conducted to investigate any relevant reports on the subject matter. Results Two left dry bone scapulae with unilateral osseous suprascapular canal were found. The incidence of this atypical morphology of an osseous canal is probably five cases reported in three studies including this cases study. Conclusions The reported cases aid in explaining additional possible anatomical factors that could lead to below threshold anesthetic effect in posterior suprascapular nerve block procedures. Therefore, it is more practical to visualize the suprascapular canal by some imaging method before attempting to blindly access the suprascapular nerve in nerve block or posterior surgical approach due to the rare potential existence of an ossified barrier hindering the procedure. Level of evidence V Basic Science Research.

Diploic veins (DV) run within the cranial diploe, where they leave channels that can be studied in osteological samples. This study investigates overall DV variability in human adults and the effects of sex, age, cranial dimensions, and dysmorphogenesis associated with craniosynostosis (CS). The morphology of macroscopic diploic channels was analyzed in a set of the qualitative and quantitative variables in computed tomography‐images of crania of anatomically normal and craniosynostotic adult individuals. Macroscopic diploic channels occur most frequently in the frontal and parietal bones, often with a bilaterally symmetrical pattern. DV‐features (especially DV‐pattern) are characterized by high individual diversity. On average, there are 5.4 ± 3.5 large macroscopic channels (with diameters >1 mm) per individual, with a mean diameter of 1.7 ± 0.4 mm. Age and sex have minor effects on DV, and cranial proportions significantly influence DV only in CS skulls. CS is associated with changes in the DV numbers, distributions, and diameters. Craniosynostotic skulls, especially brachycephalic skulls, generally present smaller DV diameters, and dolichocephalic skulls display increased number of frontal DV. CS, associated with altered cranial dimensions, suture imbalance, increased intracranial pressure, and with changes of the endocranial craniovascular system, significantly also affects the macroscopic morphology of DV in adults, in terms of both structural (topological redistribution) and functional factors. The research on craniovascular morphology and CS may be of interest in biological anthropology, paleopathology, medicine (e.g., surgical planning), but also in zoology and paleontology.

Age-at-death estimation of adult skeletal remains is a key part of biological profile estimation, yet it remains problematic for several reasons. One of them may be the subjective nature of the evaluation of age-related changes, or the fact that the human eye is unable to detect all the relevant surface changes. We have several aims: (1) to validate already existing computer models for age estimation; (2) to propose our own expert system based on computational approaches to eliminate the factor of subjectivity and to use the full potential of surface changes on an articulation area; and (3) to determine what age range the pubic symphysis is useful for age estimation. A sample of 483 3D representations of the pubic symphyseal surfaces from theossa coxaeof adult individuals coming from four European (two from Portugal, one from Switzerland and Greece) and one Asian (Thailand) identified skeletal collections was used. A validation of published algorithms showed very high error in our dataset—the Mean Absolute Error (MAE) ranged from 16.2 and 25.1 years. Two completely new approaches were proposed in this paper: SASS (Simple Automated Symphyseal Surface-based) and AANNESS (Advanced Automated Neural Network-grounded Extended Symphyseal Surface-based), whose MAE values are 11.7 and 10.6 years, respectively. Lastly, it was demonstrated that our models could estimate the age-at-death using the pubic symphysis over the entire adult age range. The proposed models offer objective age estimates with low estimation error (compared to traditional visual methods) and are able to estimate age using the pubic symphysis across the entire adult age range.