Sex determination of human crania using Mastoid triangle and Opisthion–Bimastoid triangle

The Relationship Between Craniocervical Morphology and the Presence and Level of Cervical Facet Joint Degeneration

OBJECTIVE

To investigate the relationship between craniocervical morphology and the presence and level of cervical facet joint degeneration (FJD).

METHODS

A total of 108 consecutive female patients aged 45-55 years who had undergone neck + brain CT angiography were included in this retrospective sectional study. Only patients of a certain age and of the same gender were included in order to eliminate the differences that create a disposition to the development of spinal degeneration. The presence of facet joint (FJ) arthritis (grade ≥2 degeneration in at least one affected facet joint) and the grade of the facet joint degeneration for each patient were recorded. A total of 20 lengths and 3 angles of craniocervical morphology were measured. The differences between the individuals with and without FJ arthritis were investigated with the independent-sample t test, and the relationship between the FJD grade and craniocervical morphology was investigated using the Spearman correlation test.

RESULTS

Individuals with FJ arthritis were found to have longer Grabb-Oakes measurement, shorter FM AP length, lower ADI, lower EOP thickness, higher clivus length, higher crista gall-ATS distance, lower CCA angle, lower distance between the C1 vertebra lateral masses, and higher BAI than those without FJ arthritis (P ˂ 0.05). Besides, we found that the FJD grade increased as the Grabb-Oakes measurement increased, ADI distance decreased, FM AP length decreased, EOP thickness decreased, clivus length increased, basal angle increased, distance between the C1 vertebra lateral masses decreased, and BAI increased (P ˂ 0.05).

CONCLUSIONS

Differences in craniocervical morphology are statistically associated with degenerative processes that result in degenerative changes in the facet joint. Therefore, some morphological changes in craniocervical anatomy cause changes in the momentum and distribution of the load on the facet joints, predisposing the patient to facet arthropathy and osteoarthritis.

Sex determination by Ct -scan analysis of the mastoid bone: A cross-sectional study

The mastoid bone, situated at the base of the skull and characterized by its compact structure in the petrous portion, being among the slowest-growing bones, has gained recognition as a valuable anthropological tool for sex determination. Thus, we have proposed to assess the reliability of the mastoid process in sex determination in a Tunisian population using CT-scan analysis. A cross-sectional study was conducted. CT scans forming the mastoid triangle were analyzed using a General Electric Bright Speed scanner. Nine measurements were taken by a single observer, ensuring reliability through intra- and inter-observer assessments. Normalization and statistical analyses, including logistic regression, were applied to identify sex-discriminating variables. The model's performance was evaluated using learning curves, cross-validation, and various metrics. The resulting logistic regression equation, coefficients, and intercept provided a predictive tool for sex determination. A total of 256 cranial CT scans (126 males, 130 females) were analyzed. Our study revealed that the mastoid region approach achieved an overall accuracy of 80.8 % in sex identification within the examined population. The method demonstrated a sensitivity of 78.9 % and specificity of 81.8 %. All investigated variables (AP, PM, AM, CMH, TMH, OSDmax, OCDmax, MA) exhibited discriminatory capabilities for sex determination, except for AIA. Notably, the most effective discriminators were AP, CMH, and OSDmax. Utilizing an ROC curve analysis to optimize mastoid variables for maximum sensitivity and specificity, we obtained excellent results, with an area under the curve reaching 91 %.

Sex Estimation From Measurements of the Mastoid Triangle and Volume of the Mastoid Air Cell System Using Classical and Machine Learning Methods: A Comparative Analysis

ABSTRACT

Previous studies on the sexual dimorphism of the mastoid triangle have typically focused on linear and area measurements. No studies in the literature have used mastoid air cell system volume measurements for direct anthropological or forensic sex determination. The aims of this study were to investigate the applicability of mastoid air cell system volume measurements and mastoid triangle measurements separately and combined for sex estimation, and to determine the accuracy of sex estimation rates using machine learning algorithms and discriminant function analysis of these data. On 200 computed tomography images, the distances constituting the edges of the mastoid triangle were measured, and the area was calculated using these measurements. A region-growing algorithm was used to determine the volume of the mastoid air cell system. The univariate sex determination accuracy was calculated for all parameters. Stepwise discriminant function analysis was performed for sex estimation. Multiple machine learning methods have also been used. All measurements of the mastoid triangle and volumes of the mastoid air cell system were higher in males than in females. The accurate sex estimation rate was determined to be 79.5% using stepwise discriminant function analysis and 88.5% using machine learning methods.

Estimation of sex from computed tomography images of skull measurements in an adult Turkish population

BACKGROUND

Nowadays, data on the anthropometric measurements of populations is needed in many areas, especially forensic and legal. Using various methods, researchers obtain various data such as race, sex, and age, and thus provide identification of the material used. Morphological or metric methods are often used for identification.

PURPOSE

To evaluate the usefulness of the results of skull measurements using computed tomography (CT) to determine sex in a Turkish population.

MATERIAL AND METHODS

We analyzed 300 male and 300 female CT images of Turkish individuals with an age range of 21-50 years. Maximum cranial length, maximum cranial breadth, bimastoid diameter, bizygomatic diameter, and bigonial breadth were measured by CT tomography. All data were subjected to discriminant function analyses for estimating sex. Intra-observer and inter-observer variances of the measurements were examined using intraclass correlation coefficient analysis.

RESULTS

Discriminant function analysis indicated that there was a significant difference between male and female with 88% accuracy. Discriminant function for estimation of sex was obtained with satisfactory accuracy rates for the parameters used.

CONCLUSION

This study confirms that skull measurements show sexual dimorphism in the Turkish population, and also suggests that it may be useful to use CT to assess skull anthropometric measurements.

Sex estimation from foramen magnum parameters in adult Turkish population: A computed tomography study

Identification of skeletal relics is crucial for medicolegal purposes. Sex estimation is one of the critical parts providing the identification of skeletal relics. In forensic practice, sex estimation requires multidisciplinary studies of such as forensic medicine, anatomy, dentistry and radiology. Recently, radiological studies on this subject have been increasing with the developing technology. The objective of this study is to examine the usage of radiological dimensions of foramen magnum for sex estimation in human skulls by developing discriminant functions in Turkish population. We analyzed 600 (300 males and 300 females) Computerized Tomography (CT) images of Turkish individuals aged between 21 and 50. Four measurements were obtained from CT images. All measurements in males were significantly greater than in females, and they provided the higher sex classification accuracy. The area of the foramen magnum calculated by Radinsky's formula was the best measurement for sex estimation with a 75% accuracy rate. In conclusion, the CT images of foramen magnum show sexual dimorphism in our population. To use population specific data would be the most appropriate approach for sex estimation.

Comparative analysis of four morphometric methods for sex estimation: A study conducted on human skulls

The pelvis and skull are the regions of the human skeleton that most clearly show sexual dimorphism, with the pelvis being superior to the skull for sex estimation owing to reproductive and hormonal factors. However, as many skeletons are found incomplete, it is important to be able to determine sex from analyzing the skull as well as the pelvis. This study was aimed at validating and evaluating the effectiveness of four morphometric methods for sex estimation using the human skull. One hundred human Brazilian skulls belonging to identified but unclaimed skeletons were used after all legal and administrative requirements for exhumation were satisfied. Four dimensions were analyzed: the facial triangle; the bimastoid triangle; the mastoid triangle; and finally, the occipital triangle. These dimensions were used to calculate the triangle areas. Descriptive analysis was used to verify the mean, standard deviation, and confidence interval of all variables and discriminant analysis with cross-validation was used to verify the percentage of correctness of the sex estimation methods. Individual analysis of the areas of the facial, right mastoid, left mastoid, bimastoid, and occipital triangles, and sum of the mastoid triangle areas, produced average accuracies of 63.0%, 81.8%, 77.8%, 71.4%, 64.0%, and 80.8%, respectively. Combinations of triangles resulted in higher mean accuracy percentages, with only 75.6% accuracy recorded when the left and right mastoid triangle areas were removed. All average values of analyzed triangles were higher in males than in females. Analyses of the cranial triangles were useful for sex estimation in the population studied.

Investigating the sex-related geometric variation of the human cranium

Accurate sexing methods are of great importance in forensic anthropology since sex assessment is among the principal tasks when examining human skeletal remains. The present study explores a novel approach in assessing the most accurate metric traits of the human cranium for sex estimation based on 80 ectocranial landmarks from 176 modern individuals of known age and sex from the Athens Collection. The purpose of the study is to identify those distance and angle measurements that can be most effectively used in sex assessment. Three-dimensional landmark coordinates were digitized with a Microscribe 3DX and analyzed in GNU Octave. An iterative linear discriminant analysis of all possible combinations of landmarks was performed for each unique set of the 3160 distances and 246,480 angles. Cross-validated correct classification as well as multivariate DFA on top performing variables reported 13 craniometric distances with over 85% classification accuracy, 7 angles over 78%, as well as certain multivariate combinations yielding over 95%. Linear regression of these variables with the centroid size was used to assess their relation to the size of the cranium. In contrast to the use of generalized procrustes analysis (GPA) and principal component analysis (PCA), which constitute the common analytical work flow for such data, our method, although computational intensive, produced easily applicable discriminant functions of high accuracy, while at the same time explored the maximum of cranial variability.

Panel 2: Anatomy (Eustachian Tube, Middle Ear, and Mastoid-Anatomy, Physiology, Pathophysiology, and Pathogenesis)

Objective In this report, we review the recent literature (ie, past 4 years) to identify advances in our understanding of the middle ear-mastoid-eustachian tube system. We use this review to determine whether the short-term goals elaborated in the last report were achieved, and we propose updated goals to guide future otitis media research. Data Sources PubMed, Web of Science, Medline. Review Methods The panel topic was subdivided, and each contributor performed a literature search within the given time frame. The keywords searched included middle ear, eustachian tube, and mastoid for their intersection with anatomy, physiology, pathophysiology, and pathology. Preliminary reports from each panel member were consolidated and discussed when the panel met on June 11, 2015. At that meeting, the progress was evaluated and new short-term goals proposed. Conclusions Progress was made on 13 of the 20 short-term goals proposed in 2011. Significant advances were made in the characterization of middle ear gas exchange pathways, modeling eustachian tube function, and preliminary testing of treatments for eustachian tube dysfunction. Implications for Practice In the future, imaging technologies should be developed to noninvasively assess middle ear/eustachian tube structure and physiology with respect to their role in otitis media pathogenesis. The new data derived from these structure/function experiments should be integrated into computational models that can then be used to develop specific hypotheses concerning otitis media pathogenesis and persistence. Finally, rigorous studies on medical or surgical treatments for eustachian tube dysfunction should be undertaken.

Evaluating sexual dimorphism in the human mastoid process: A viewpoint on the methodology

The mastoid process is one of the most sexually dimorphic features in the human skull, and is therefore often used to identify the sex of skeletons. Numerous techniques for assessing variation in the size and shape of the mastoid process have been proposed and implemented in osteological research, but its complex form still presents difficulties for consistent and effective analysis. In this article, we compare the different techniques and variables that have been used to define, measure, and visually score sexual dimorphism in the mastoid process. We argue that the current protocols fail to capture the full morphological range of this bony projection, and suggest ways of improving and standardizing them, regarding both traditional and 3D-based approaches.

Morphologic Variations of Clinically Normal Mallei and Incudes

Objectives:

Various features and shapes of malleus and incus are reported. Partially or unaddressed are their bilateral symmetry, correlation with otitis media, and concordance of features and shapes. Such information may contribute to the understanding of malleus and incus ontogeny and the installation and function of implantable middle ear devices. We sought to address the following hypotheses: (1) a cranium’s malleus and incus have bilateral symmetry, with respect to their features and shapes; (2) features and shapes of malleus and incus are unrelated to the mastoid size indicator of childhood otitis media; and (3) an ear’s malleus and incus have concordant features and shapes (ie, the presence or absence of a feature or shape of a malleus or incus is associated with the presence or absence of another feature or shape in that ear’s malleus or incus).

Methods:

Postmortem material-analysis prevalence study of 41 adult crania without clinical otitis media. Mastoid sizes were assessed radiographically.

Results:

Most mallei had lateral processes and inflected manubrium tips. Most incudes had concave superior borders of their short processes, non-notched inferior borders of their short processes, and anteriorly curved anterior edges of their long processes. Only 1 feature, absence of the lateral process of the malleus, was suggested to have a relationship to small mastoid size. Concordance was not found for any shape or feature of the malleus or incus.

Conclusion:

Clinically normal mallei and incudes have feature and shape variations that are mostly bilaterally symmetric.