Standardization of Cephalograms Obtained From Various Imaging Systems

Objective To propose and validate a method for standardizing and printing cephalograms acquired from different imaging systems. Methods Validation of the proposed method was done using digital cephalograms, cone beam computed tomography (CBCT)-derived cephalograms, and direct measurements obtained from 3 dry human skulls. Each cephalogram was analyzed as-received and after standardization, using both manual and digital methods. 3-dimensional (3D) measurements were also computed from the CBCT images. After adequate blinding, 2 observers independently carried out all these measurements at 2 different times. Finally, the different cephalometric measurements of each skull were compared with the corresponding direct measurements (gold standard). Results The as-received digital cephalogram showed an inherent magnification of 33%, as determined from the calibration ruler. Compared to direct skull measurements, the as-received conventional and CBCT-derived cephalograms printed without standardization showed a reduction in measures of around 14% and 28%, respectively, whereas measurements obtained from cephalograms, which were standardized and printed by the proposed method, were comparable to direct measurements. Conclusions The findings of the validation study demonstrate the robustness of the proposed method in standardizing different cephalograms before printing.

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.

Common Patterns of Skull Bone Fusion and Their Potential to Discriminate Different Ontogenetic Stages in Extant Birds

The degree of sutural closure between bones generally allows for the classification of skeleton maturity in tetrapods. In mammals, the sutural closure of skull bones was previously used as proxy to evaluate the ontogenetic stage of single individuals. However, due to temporal variation, this process can be only applied among mammalian subclades, but not for all mammals in general. In contrast, the process of sutural closures in bird skulls could be a more reliable ontogenetic proxy for this clade as adult birds commonly show a generally high degree of bone fusion. To test this, we studied the process of sutural closure in ontogenetic series of 18 extant bird species regarding the presence of an ontogenetic signal and compared the results with changes in skull size and proportions. Univariate analyses indicate that bone fusion happens faster in altricial than in precocial birds. However, the use of PCoA and multivariate regressions reveal that the skull bone fusion follows a common pattern among birds and thus can be used as proxy to identify different ontogenetic stages. In general, the process of sutural closure spreads from posterior to anterior and from ventral to dorsal. In contrast, skull measurements reflect rather interspecific allometry than ontogeny. The used of bone fusion as proxy will help to better identify and compare different stages of maturation in birds, including historical material from osteological collections.

Morphometric analysis of the sella turcica in Northeastern Brazil

Introduction: The sella turcica is a structure of the median region of the sphenoid bone. Variations in its morphology are relevant as it is a region subjected to several surgical procedures, mainly related to the pituitary gland. Objective: To analyze the morphology of the sella turcica and its sexual dimorphism in Northeastern Brazil. Methods: Fifteen human skulls from the Federal University of Paraíba (UFPB) were used. The qualitative analysis was performed by classifying the shape of the sella turcica into three types: U, J and flattened. Morphometric data was collected and statistically analyzed to evaluate the relationship between sella morphometry and gender, and between sella and skull measurements. Values of p< 0.05) in the sella turcica length (STL) and skull length (SL), with male skulls being larger in both cases. The other linear measurements didn’t show differences between the sexes (p>0.05). There was a positive linear correlation between STL and SL, and a negative linear correlation between sella turcica width (STW) and sella turcica height (STH) and between STH and bitemporal width (BTW). Conclusion: The results point to important differences in the morphometric parameters evaluated with original findings for this population. Knowledge of the morphology of the sella is essential to plan safer surgical approaches in the pituitary gland or related anatomical structures.

Man’s measures. Piotr Mitzner and fundamental anthropological questions

The articles concerns various possibilities of interpreting Piotr Mitzner’s poem Jest miarąfrom the volume of poems I po kropce (2013). Three important interpretative contexts for Mitzner’s poem can be identifi ed: 1) different ways of understanding Protagoras’ maxim anthroposmetron consi-dered to be the „magnacharta of Western relativism” (G. Reale); 2) the theoretical and practical implications of the development of craniometry, with its connections to the physical and cultural anthropology of the 19th and 20th centuries (along with references to the ideological use of human skull measurements i.e. during the 2nd World War), the refl ection on human cognitive limitations. The formal aspects of Mitzner’s poem that are crucial for its analysis include repetitions, rhythm and graphic and sound arrangement as well as the construction of the implied subject.

Breeding of the Gull-billed Tern in the Sahara and an update on its distribution in Algeria

The taxonomic status of the gerbil Gerbillus amoenus in relation to Gerbillus nanus and the distribution range of these two species in Africa and/or Asia have long been debated and are not yet fully clarified. In our study, we identify two specimens of small gerbils that we captured in two localities of the south of Morocco, using morphometric and/or molecular tools. The body and skull measurements were not able to unambiguously discriminate between three closely related small gerbils (Gerbillus amoenus, Gerbillus nanus and Gerbillus henleyi). However, the cytochrome b gene analysis showed that our two specimens cluster unambiguously with haplotypes of G. amoenus. This represents the first genetic characterization of G. amoenus in Morocco. It confirms, based on mitochondrial DNA, that the previously described species living in Africa is indeed G. amoenus and not G. nanus, the latter species being present strictly in Asia.

Body Size and Bite Force of Stray and Feral Cats—Are Bigger or Older Cats Taking the Largest or More Difficult-to-Handle Prey?

As carnivorans rely heavily on their head and jaws for prey capture and handling, skull morphology and bite force can therefore reflect their ability to take larger or more difficult-to-handle prey. For 568 feral and stray cats (Felis catus), we recorded their demographics (sex and age), source location (feral or stray) and morphological measures (body mass, body condition); we estimated potential bite force from skull measurements for n = 268 of these cats, and quantified diet composition from stomach contents for n = 358. We compared skull measurements to estimate their bite force and determine how it varied with sex, age, body mass, body condition. Body mass had the strongest influence of bite force. In our sample, males were 36.2% heavier and had 20.0% greater estimated bite force (206.2 ± 44.7 Newtons, n = 168) than females (171.9 ± 29.3 Newtons, n = 120). However, cat age was the strongest predictor of the size of prey that they had taken, with older cats taking larger prey. The predictive power of this relationship was poor though (r2 < 0.038, p < 0.003), because even small cats ate large prey and some of the largest cats ate small prey, such as invertebrates. Cats are opportunistic, generalist carnivores taking a broad range of prey. Their ability to handle larger prey increases as the cats grow, increasing their jaw strength, and improving their hunting skills, but even the smallest cats in our sample had tackled and consumed large and potentially ‘dangerous’ prey that would likely have put up a defence.

Quantitative morphological characters of the skull suggest that Akodon oenos (Rodentia, Cricetidae, Sigmodontinae) is not a junior synonym of A. spegazzinii

Akodon oenos, a nominal form with type locality in northern Mendoza province, Argentina, has an intricate taxonomic history. Recently, it was considered a junior synonym of Akodon spegazzinii on the basis of morphological similarities of one individual captured in southern Mendoza with specimens belonging to the type series of A. oenos, plus the genetic similarity of that single specimen with representatives of A. spegazzinii. We compared specimens of the Akodon boliviensis species group recently captured in Mendoza with the type series of A. oenos and series of A. spegazzinii from northwestern Argentina. We conducted an analysis of molecular markers (cytochrome-b gene) and quantitative morphological studies (comparisons of skull measurements). Our results showed that: (1) all sequenced specimens of the A. boliviensis group from Mendoza form a monophyletic clade closely related to A. spegazzinii; (2) contrary to previous hypothesis, specimens of Akodon from Mendoza are morphologically distinctive in size and shape of the skull, from A. spegazzinii; and (3) within the A. boliviensis species group, specimens from Mendoza are distinctive. We argue that the synonymy of A. oenos under A. spegazzinii must await further studies, including molecular markers other than mitochondrial and samples of DNA sequences from topotypical specimens of A. oenos.

Accuracy of linear measurements obtained from stitched cone beam computed tomography images versus direct skull measurements

Background: To assess whether the linear measurements obtained from stitched cone beam computed tomography (CBCT) images were as accurate as the direct skull measurements. Methods: Nine dry human skulls were marked with gutta-percha at reference points to obtain Twenty-two linear measurements on each skull. Ten measurements in the cranio-caudal plane, two measurements in the antero-posterior plane, and ten measurements in the medio-lateral plane. CBCT linear measurements obtained using stitching software were measured and compared with direct skull measurements. Results: The absolute Dahlberg error between direct linear measurements and linear measurements on stitched CBCT images ranged from (0.07 mm to 0.41 mm). The relative Dahlberg error ranged from (0.2% to 1.8%). Moreover, Intra-class Correlation Coefficient (ICC) ranged from (0.97 to 1.0) indicating excellent agreement. Conclusion: Stitched CBCT linear measurements were highly comparable to the direct skull measurements using a digital caliper.