Skull Characters Research Articles

Comparison of the impact of skull density ratio with alternative skull metrics on magnetic resonance-guided focused ultrasound thalamotomy for tremor.

One of the key metrics that is used to predict the likelihood of success of MR-guided focused ultrasound (MRgFUS) thalamotomy is the overall calvarial skull density ratio (SDR). However, this measure does not fully predict the sonication parameters that would be required or the technical success rates. The authors aimed to assess other skull characteristics that may also contribute to technical success. The authors retrospectively studied consecutive patients with essential tremor who were treated by MRgFUS at their center between 2017 and 2021. They evaluated the correlation between the different treatment parameters, particularly maximum power and energy delivered, with a range of patients' skull metrics and demographics. Machine learning algorithms were applied to investigate whether sonication parameters could be predicted from skull density metrics alone and whether including combined local transducer SDRs with overall calvarial SDR would increase model accuracy. A total of 62 patients were included in the study. The mean age was 77.1 (SD 9.2) years, and 78% of treatments (49/63) were performed in males. The mean SDR was 0.51 (SD 0.10). Among the evaluated metrics, SDR had the highest correlation with the maximum power used in treatment (ρ = -0.626, p < 0.001; proportion of local SDR values ≤ 0.8 group also had ρ = +0.626, p < 0.001) and maximum energy delivered (ρ = -0.680, p < 0.001). Machine learning algorithms achieved a moderate ability to predict maximum power and energy required from the local and overall SDRs (accuracy of approximately 80% for maximum power and approximately 55% for maximum energy), and high ability to predict average maximum temperature reached from the local and overall SDRs (approximately 95% accuracy). The authors compared a number of skull metrics against SDR and showed that SDR was one of the best indicators of treatment parameters when used alone. In addition, a number of other machine learning algorithms are proposed that may be explored to improve its accuracy when additional data are obtained. Additional metrics related to eventual sonication parameters should also be identified and explored.

Assessing the Taxonomic Status of the Gray Brocket Mazama simplicicornis argentina Lönnberg, 1919 (Artiodactyla: Cervidae).

Mazama simplicicornis argentina is the name that was given to describe a gray brocket collected by Lönberg in 1919 in the central Chaco region of Argentina. Subsequent authors, based on morphological similarities, considered this name to be a synonym for the species Subulo gouazoubira Fischer, 1814 from Paraguay. In the absence of genetic analyses to compare the Argentinian and Paraguayan gray brockets, we aimed to clarify the taxonomy of M. simplicicornis argentina through an integrative assessment using morphological, cytogenetical, and molecular data from its holotype and a current topotype. Qualitative skull features and cranio-morphometric results of M. simplicicornis argentina showed a great similarity with the S. gouazoubira neotype characters. The diploid chromosome number of M. simplicicornis argentina topotype corresponded with the karyotypical pattern of S. gouazoubira with 2n = 70 and FN = 70, showing a great similarity in all classic and molecular cytogenetic results and revealing the homologies between karyotypes. The phylogenetic analysis of mitochondrial genes used in this study (concatenated partial ND5 and Cytb gene) allocated the M. simplicicornis argentina specimens in the monophyletic clade of S. gouazoubira with a branch value of 100%. These results show that there is no discontinuity between the Argentinian and Paraguayan gray brockets. Therefore, the individuals originally described as M. simplicicornis argentina should be recognized as S. gouazoubira.

Size reduction and skull shape parallelism following the evolutionary forest-to-savanna transition in Platyrrhini monkeys.

There are strong physiological and behavioral differences that allow animals to live in forests versus savannas. For example, terrestrial forest-dwelling mammals tend to be small compared to species living in savannas. Robust capuchin monkeys (genus Sapajus) are widespread in tropical South America, occurring in both forest and savanna environments, with forest species considered basal in an evolutionary context. Whether or not skull shape and size variations are associated with variation in resource use remains unknown, particularly for the two species living in savanna (Sapajuslibidinosus and S. cay). Here we show that savanna species present convergent size and skull characteristics that may facilitate living in this new environment. Geometric morphometric methods were used to assess skull size and shape variation for 184 Sapajus specimens distributed across South America. We used phylogenetic generalized least squares to test size against environmental variables and multivariate morphological trajectories/partial least square analyses on the skull shape to detect shape differences in specimens between forest and savanna biomes. Our findings reveal Sapajus size reduction in the evolutionary transition from forest to savanna, a process related to increasing seasonality. Moreover, we found morphological parallelism in the skull (e.g., muzzle shortening) and (large) molars in the two savanna species, features that may facilitate the processing of harder food such as fallback resources. We associate these phenotypic differences to the evolutionary process of colonizing the savannas by primates (including early hominins), leading to morphological adaptations to tolerate stressful, seasonal environments, such as body size reduction and ingestion and mastication of tough foods.

Update: Assessing the evolutionary trajectory of the Apaporis caiman (Caiman crocodilus apaporiensis, Medem 1955) via mitochondrial molecular markers

Abstract The spectacled caiman (Caiman crocodilus) is currently considered to be a species complex due to the relatively high morphological and molecular diversity expressed across its range. One of the populations of interest, inhabiting the Apaporis River (Colombia), was described based on skull features as an incipient species (C. c. apaporiensis) and has been treated by some authors as a full species. Recent molecular work challenged this hypothesis, because relatively low mitochondrial molecular differentiation was found between the morphologically described Apaporis caiman and C. crocodilus (s.s.) Amazonian populations. Here, we present an update on the topic based on a larger molecular sample size and on analysis of expanded geometric morphometric data that include six newly collected skulls. Morphometric data support the existence of previously recognized morphotypes within the complex in Colombia and demonstrate that the newly collected material can be assigned to the classic Apaporis caiman morphotype. However, our expanded genetic analysis fails to find appreciable mitochondrial molecular divergence of the Apaporis caiman population from the C. c. crocodilus population (COI-CytB: Amazon Peru 0.17 ± 0.06%, CytB-only: Caquetá River Colombia 0.08 ± 0.07%). The Apaporis caiman is interpreted to be a phenotypically distinct member of the cis-Andean C. crocodilus metapopulation that has not yet achieved (or may not be undergoing at all) appreciable genetic differentiation. Thus, it should not be considered a fully independent evolutionary lineage, nor given full species rank.

The Precise Location of the Stylomastoid Foramen and Clinical Implication for Facial Nerve Block

Aim: We aimed to develop linear regression formulas for determining the precise localization of the stylomastoid foramen on the base of the morphometric features of the person’s own skull. &#x0D; Material and Method: The study was conducted on 22 stylomastoid foramina (11 skulls). The 10 parameters determined for the stylomastoid foramen were measured on the photographs taken from the skull base and the 17 parameters determined for the morphometric features of the skull were measured on the photographs taken from the anterior plane, lateral plane, and posterior plan using Image J measurement software. The data obtained were evaluated with SPSS 20.0 statistical software. &#x0D; Results: To determine the morphometric and topographic features of the stylomastoid foramen the equations have been developed such as; P1 (The distance between stylomastoid foramen and root of the zygomatic arch)=18.758+(0.472xP12)-(2.092x P16)+(0.831xP17)–(0.390xP18)–(0.101x P20); Adjusted R2=0.865, Standard Error of the Estimation=1.389. &#x0D; Conclusion: Mean values can give misleading information in determining the topographical relationship between the stylomastoid foramen and the surrounding anatomical structures. We have developed regression formulas that will estimate the accurate location of the stylomastoid foramen and the accurate distances between other surrounding anatomical structures, taking into account the morphometric characteristics of the person’s own skull.

Physiology: Woodpecker skulls are not shock absorbers

Woodpeckers are well-known for their audible percussive wood drilling. A new study shows that these birds benefit from their small size and key skull features to safely hammer at wood for insect food and nesting excavations.

Flexible conservatism in the skull modularity of convergently evolved myrmecophagous placental mammals

BackgroundThe skull of placental mammals constitutes one of the best studied systems for phenotypic modularity. Several studies have found strong evidence for the conserved presence of two- and six-module architectures, while the strength of trait correlations (integration) has been associated with major developmental processes such as somatic growth, muscle-bone interactions, and tooth eruption. Among placentals, ant- and termite-eating (myrmecophagy) represents an exemplar case of dietary convergence, accompanied by the selection of several cranial morphofunctional traits such as rostrum elongation, tooth loss, and mastication loss. Despite such drastic functional modifications, the covariance patterns of the skull of convergently evolved myrmecophagous placentals are yet to be studied in order to assess the potential consequences of this dietary shift on cranial modularity.ResultsHere, we performed a landmark-based morphometric analysis of cranial covariance patterns in 13 species of myrmecophagous placentals. Our analyses reveal that most myrmecophagous species present skulls divided into six to seven modules (depending on the confirmatory method used), with architectures similar to those of non-myrmecophagous placentals (therian six modules). Within-module integration is also similar to what was previously described for other placentals, suggesting that most covariance-generating processes are conserved across the clade. Nevertheless, we show that extreme rostrum elongation and tooth loss in myrmecophagid anteaters have resulted in a shift in intermodule correlations in the proximal region of the rostrum. Namely, the naso-frontal and maxillo-palatine regions are strongly correlated with the oro-nasal module, suggesting an integrated rostrum conserved from pre-natal developmental processes. In contrast, the similarly toothless pangolins show a weaker correlation between the anterior rostral modules, resembling the pattern of toothed placentals.ConclusionsThese results reveal that despite some integration shifts related to extreme functional and morphological features of myrmecophagous skulls, cranial modular architectures have conserved the typical mammalian scheme.

Quasi-static compressive mechanical properties of multilayer micro-lattice biomaterials for skull repair

Current skull repair biomaterials used in clinical surgery face problems such as unmatched mechanical properties and poor biocompatibility. To overcome these problems, the multilayer micro-lattice biomaterials (MB) combining both suitable mechanical properties and biocompatibility are proposed based on skull structural characteristics. The quasi-static compressive mechanical properties of MB are studied experimentally, numerically and theoretically, which are verified by experimental results. The typical deformations, such as distinct shear zone and stress concentration of nodes, are observed. The strength and modulus of the above MB specimens are in the range of 86.72 ± 0.84 to 197.73 ± 0.74 MPa and 2.99 ± 0.13 to 7.56 ± 0.54 GPa, respectively. Simultaneously, the properties of MB with gradient design, including positive, negative and hybrid gradient are investigated by finite element (FE) simulation. The MB with hybrid gradient can better match the structural characteristics of skull. Since the designed MB has out-of-plane compression characteristics comparable to that of skull and suitable biological space for cell growth, it can be implanted into the human body to matched surrounding skull tissue well. The insight of MB combining with design constraints of biomaterials provides a novel method for designing/tuning skull repair biomaterials that might result in the optimized clinical skull surgery effect.

Record of a juvenile Omura's whale live stranded in Hainan Island: Evidence of a potential breeding ground in the South China Sea?

On January 12, 2011, a very young juvenile Bryde's-like baleen whale was found stranded alive on the east coast of Hainan Island, in the South China Sea. Unfortunately, it died the next morning. This baleen whale showed some unique external morphology and skull features of the Omura's whale (Balaenoptera omurai). Subsequently, it was genetically identified as an Omura's whale using two different mitochondrial DNA markers. This study documents the first confirmed live stranding of a juvenile Omura's whale on Hainan Island, China. Our findings expand the known distribution range of this species in Chinese waters and may indicate that waters around Hainan Island in the South China Sea could be a potential breeding ground for the Omura's whale.

A post-mortem computed tomography imaging method for predicting the anteroposterior and superoinferior positions of the Japanese adult eyeball in the orbit

: Predicting the position of the human eyeball is particularly difficult in facial approximation. While prediction methods for eyeball position based on skull features have been proposed in Caucasians, this study aimed to establish a method using anatomical landmarks on Mongoloid skulls. : Using post-mortem computed tomography (PMCT) images, we plotted landmarks on the skull and soft tissues of 146 Japanese adult cadavers and recorded the coordinates using CT image viewer software (OSIRIX MD, Pixmeo). We measured the distances between these landmarks and processed the data statistically in Microsoft Excel®>. : The results showed significant differences for many variables compared to previous guidelines and measurements, suggesting the need for a prediction method based on ancestry. We identified factors such as sex, body mass index, and age that influenced eyeball location. Next, we estimated the prediction standards of the globe position from the measurements obtained in this study and applied them to unidentified cadavers. The correlation coefficient was 0.737 in the anteroposterior direction and 0.291 in the superoinferior direction. The small correlation coefficient for eye protrusion was likely based on the lack of power, owing to the limited number of samples in the database. : Important factors in predicting facial features, such as sex, age, and ancestry, contributed to more accurate facial approximation. Future analyses using a larger database to establish more accurate prediction guidelines are necessary.

Unexpected cranial sexual dimorphism in the tragulid Dorcatherium naui based on material from the middle to late Miocene localities of Eppelsheim and Hammerschmiede (Germany).

Tragulids, chevrotains or mouse deer, were common faunal elements during the Miocene. During that time, Dorcatherium was the most abundant genus, with D. naui being the first described species. Besides their abundance, until recently only very limited cranial material was available for investigation. Here we present a redescription of the first complete skull of D. naui from the middle to late Miocene locality of Eppelsheim, Germany, based on micro-computed tomography. Furthermore, we present a description and comparison of two additional, new skulls of D. naui from the late Miocene hominid locality Hammerschmiede, Germany. Within Dorcatherium, so far, only three other complete skulls are known, all belonging to D. crassum. A comparison between the three skulls of D. naui and the already known skulls of D. crassum shows that these two species differ in morphological features of the skull, such as laterally facing orbitae, separation of supraorbital foramen from supraorbital groove by a bony bridge, well-developed parietal plateau, prominent nuchal tubercle, less-developed nuchal crests, and the presence of an occipital crest. Moreover, two different osteological morphotypes are present in the skulls of D. naui that can be interpreted as a previously unknown sexual dimorphism. Very similar features are observed in D. crassum, which can be likewise related to the same dimorphism. However, males of D. naui differ from males of D. crassum by the presence of frontoparietal bulges, which were probably used for sexual display and during male-male combats in males of D. naui. For the first time, sexual dimorphism in Dorcatherium is described based on skull characteristics, which are, so far, unknown from any other fossil or extant tragulid.

A new species of Tamiops (Rodentia, Sciuridae) from Sichuan, China.

During a small mammal survey in Wanglang National Natural Reserve, Sichuan, China in AugustOctober 2018, we collected four specimens of an Asiatic striped squirrel (genus Tamiops) that could not be assigned morphologically to any described species. Phylogenetic analyses of CYTB and nuDNA sequences strongly supported them in the genus Tamiops. The p-distances of CYTB between these individuals and other species of Tamiops ranged from 17.4 to 19.1%. Morphologically, they differed from their congeners, including T. maritimus, T. mcclellandii, T. rodolphii, and T. swinhoei by pelage, skull, and baculum characteristics. Based on the results of morphological comparisons and molecular analyses, we describe the four specimens as the new species Tamiops minshanica sp. nov.

Morphometric study of the ventricular indexes in healthy ovine BRAIN using MRI

BackgroundSheep (Ovis aries) have been largely used as animal models in a multitude of specialties in biomedical research. The similarity to human brain anatomy in terms of brain size, skull features, and gyrification index, gives to ovine as a large animal model a better translational value than small animal models in neuroscience. Despite this evidence and the availability of advanced imaging techniques, morphometric brain studies are lacking. We herein present the morphometric ovine brain indexes and anatomical measures developed by two observers in a double-blinded study and validated via an intra- and inter-observer analysis.ResultsFor this retrospective study, T1-weighted Magnetic Resonance Imaging (MRI) scans were performed at 1.5 T on 15 sheep, under general anaesthesia. The animals were female Ovis aries, in the age of 18-24 months. Two observers assessed the scans, twice time each. The statistical analysis of intra-observer and inter-observer agreement was obtained via the Bland-Altman plot and Spearman rank correlation test.The results are as follows (mean ± Standard deviation):Indexes: Bifrontal 0,338 ± 0,032 cm; Bicaudate 0,080 ± 0,012 cm; Evans’ 0,218 ± 0,035 cm; Ventricular 0,241 ± 0,039 cm; Huckman 1693 ± 0,174 cm; Cella Media 0,096 ± 0,037 cm; Third ventricle ratio 0,040 ± 0,007 cm.Anatomical measures: Fourth ventricle length 0,295 ± 0,073 cm; Fourth ventricle width 0,344 ± 0,074 cm; Left lateral ventricle 4175 ± 0,275 cm; Right lateral ventricle 4182 ± 0,269 cm; Frontal horn length 1795 ± 0,303 cm; Interventricular foramen left 1794 ± 0,301 cm; Interventricular foramen right 1,78 ± 0,317 cm.ConclusionsThe present study provides baseline values of linear indexes of the ventricles in the ovine models. The acquisition of these data contributes to filling the knowledge void on important anatomical and morphological features of the sheep brain.

Osteology of the cranium and Weberian apparatus of African catfish families (Teleostei: Ostariophysi: Siluriformes) with an assessment of Palaeogene genera

Although the vast majority of fossil catfish material is isolated elements such as fin spines, a number of fossil catfishes (Siluriformes) have been named based on articulated crania from Palaeogene formations of Africa. The fossil taxa from marine sediments have been assigned to the extant marine family Ariidae, or have been assumed to have washed into marine sediments from freshwater habitats. The ability to assess the relationships of these fossils without reference to the nature of the geological sediments may provide insight into the history of these families. Most of the taxonomic work on the 11 catfish families found in Africa has focused on soft-tissues or DNA, which is problematic for the fossil material. Here we provide osteological features to distinguish families of African catfishes; eight of the families that are likely to be found in fossiliferous deposits can be distinguished based on a combination of skull features including the morphology of the cranial fontanelle, mesethmoid, and dermal ornamentation. We reassess the familial placement of the Palaeogene catfishes. We find that †Eomacrones wilsoni, from the Palaeocene of Nigeria, belongs in Bagridae s.s. This confirms that bagrids were in Africa much earlier than the Miocene. Because this catfish comes from Palaeocene marine sediments, the biogeographic history of Bagridae needs to be reassessed to consider marine dispersal in this taxon.

Repeatability of a morphoscopic sex estimation technique for the mental eminence on micro-focus X-ray computed tomography models

• Scoring the mental eminence trait on virtual 3D models is challenging. • A personal affinity for assessing virtual 3D models of bone may play a role. • Scores 1 and 5 were easier to score on virtual 3D models than intermediate expressions. • A more detailed definition of the mental eminence trait could be useful. Walker's sex estimation method is based on five morphoscopic features of the human skull. This study aimed at testing the repeatability of one of the five traits, the mental eminence, visually on three-dimensional (3D) models, compared to the traditional, tactile scoring approach on bone. The sample comprised 105 mandibles from the Pretoria Bone Collection and their respective virtual 3D models, obtained from micro-focus X-ray computed tomography (micro-XCT) scans. Four observers independently scored the bones first, followed by the virtual 3D modality. Intra- and interobserver errors (interOE and intraOE) were performed with Fleiss’ and Cohen's Kappa, respectively. We calculated the intermodality agreement per observer with Wilcoxon Signed-Rank tests. The intraOE was moderate on bone (κ=0.448) and substantial on 3D (κ=0.799), while the Fleiss’ Kappa test for the interOE resulted in slight agreement both on bone (κ=0.163) and 3D (κ=0.169) irrespective of level of experience. All Wilcoxon Signed-Rank test P -values were significant. The application of the morphoscopic sex estimation for the mental eminence to micro-XCTs could be a matter of personal affinity as the level of experience did not play a role in the results. The expression of the mental eminence trait being population-specific, the individual's population affinity should be considered when sex is estimated in South African skeletons. It remains unclear whether the slight agreement between observers is due to the unreliability of the trait for sex estimation or whether the modalities are not easily interchangeable.

Hyperostosis in Combination With Low Skull Density Ratio: A Potential Contraindication for Magnetic Resonance Imaging-Guided Focused Ultrasound Thalamotomy.

Since its approval in treating a number of movement disorders, magnetic resonance imaging–guided focused ultrasound (MRgFUS) has been adopted rapidly as one of the standard treatment modalities internationally. However, the efficiency of the energy delivered by the ultrasonic waves is largely determined by the highly variable bone morphology and density characteristics of the skull. One of the widely accepted indices used to facilitate patient selection is the skull density ratio (SDR). Earlier literature suggested that an SDR of less than 0.4 would be unfavorable for MRgFUS treatment. Some prior studies have excluded patients with hyperostosis. However, there is little published data regarding the impact of other skull features such as hyperostosis on treatment success. We present the case of a 66-year-old man with medically refractory essential tremor who had an SDR of 0.38 and extensive hyperostosis frontalis interna and underwent attempted MRgFUS thalamotomy treatment. However, intraoperatively the treatment was unsuccessful in generating sufficiently elevated temperature to create a lesion of the usual desired volume, and as expected, there was minimal clinical improvement. For comparison, we also summarize a case series of 4 other patients with an SDR of less than 0.4 who had successful outcomes. We believe that SDR should not be used as the only means of selecting patients for MRgFUS. Instead, important factors such as hyperostosis should be taken into consideration for patient selection and pretreatment counseling.

The History of Neuroscience 4: What is the Mechanism of the Brain? Localization Theory versus Holistic Theory

Luigi Galvani exposed the nerves of the frog leg and demonstrated twitching of the attached muscles by electrical stimulation. He could also elicit twitching of the corresponding muscles by simple metallic tapping of the nerve. Giovanni Aldini performed a theatrical demonstration of reanimation of a dead body by electrical stimulation, which also supported this view. At the start of the 19th century, Franz Joseph Gall and Johann Spurzheim proposed that the brain could be divided functionally into many parts. They also argued that the functional dominance of each individual human produced different patterns of brain development, resulting in different skull features. The basic idea that the brain was not one functional unit, but a collection of many anatomical units with different functions, was remarkable. A holistic view of brain function was reemphasized by Marie-Jean-Pierre Flourens. Flourens, who deeply believed in laboratory science, found no apparent functional changes after ablation or electrical stimulation of parts of the brain, mainly in birds. Through these experiments, Flourens harshly rebuked the idea of phrenology. Beyond this anti-phrenological role, Flourens conducted important experiments revealing the functions of the cerebellum, pons, and semicircular canals. The first widely accepted localized human brain function was language. Paul Broca presented his famous case who had developed motor aphasia with a left inferior frontal focal lesion. Eduard Hitzig and Gustav Fritsch performed an important experiment in which they identified the motor cortex of the dog brain. Finally, the excitability of the human cerebral cortex was confirmed by Roberts Bartholow. Key words: Electricity; Brain function; Phrenology.

Patient-specific effects on sonication heating efficiency during magnetic resonance-guided focused ultrasound thalamotomy.

During magnetic resonance-guided focused ultrasound (MRgFUS) thalamotomy for refractory tremor, high temperatures must be achieved and sustained for tissue necrosis. We assessed the impact of both patient-specific as well as procedure-related factors on the efficiency of acoustic energy transfer, or heating efficiency (HE). Retrospective analysis of 92 consecutive patients (857 sonications) with essential tremor or tremor-dominant Parkinson's disease treated at a single institution. Temperature elevations at the target were measured for each sonication with MR thermometry. HE of each sonication was defined as the ratio of peak temperature elevation and the delivered energy. HE was analyzed with respect to patient skull features (area, thickness, skull density ratio [SDR]), computed from CT scans, as well as demographic and clinical variables (age, sex, diagnosis, and duration of symptoms). Across the full range of sonication energies that can be delivered with current devices (up to 36kJ), average sonication HE was diminished in patients with lower SDR. In individual subjects, there was a progressive loss in HE as sonication energy was titrated up throughout the course of treatment, with a more rapid decline in patients with higher SDR. This energy-dependent loss in HE was not related to procedural factors, namely, the number of previous sonications, or the cumulative energy deposited during previous sonications. In contrast to SDR, neither skull area nor thickness was an independent predictor of average HE or the rate of its decline with increasing energies. In 11% of patients, all of whom with SDR<0.45, sonication HE fell below the threshold to reach 54°C even with delivery of maximum energy. In contrast, temperatures 50°C could be obtained in all but one patient. SDR is predictive of sonication HE, and determines patient-specific limits on the magnitude of temperature elevation that can be achieved with current devices. These data inform strategies for predictable lesioning in MRgFUS thalamotomy.

Morphometric characteristics of skull and face parameters in fetuses and newborns

Modern science has a significant number of diagnostic methods: craniological, anatomical, ultrasound, radiological. The development of new research methods, such as ultrasound and X-ray methods (magnetic resonance imaging), forms the concept of ultrasound and X-ray norms at different stages of human development. Now it is important to study the anatomical variability of people, morphometric characteristics, relationships of organs, anatomical structures, their parts at all stages of human development. The purpose of the work is to establish normative morphometric parameters of the skull and face in fetuses and newborns, followed by construction of mathematical models. The study was performed on 57 preparations of human fetuses 4-10 months and 7 newborns using adequate anatomical methods: macropreparation, topographic anatomical sections, computed tomography, craniometry. The main parameters of the facial and cerebral skull were measured with the help of a centimeter tape, a thick, sliding compass and a caliper. Statistical analysis of the obtained data was performed using a licensed program RStudio. It is established that according to the graphs of the average values of the parameters of the skull and face, there are two periods of accelerated and two periods of slow development. For transverse skull length, face width and skull height, two periods of accelerated development from the 6th to the 8th month of fetal development and from the 9th month of fetal development to the neonatal period and two periods of delayed development from the 5th to the 6th months and from the 8th to the 9th month of fetal development were revealed. For the total height of the face – periods of accelerated development – from the 4th to the 6th month of fetal development and from the 7th to the 9th month of fetal development, periods of delayed development – from the 6th to the 7th month of fetal development and from the 9th month of fetal development to the neonatal period. On the basis of arithmetic mean data of transverse skull length, face width, skull height, total face height, models for predicting normative morphometric parameters in fetuses and newborns are constructed. The constructed models will serve as a norm for the subsequent determination of certain morphometric deviations to establish variants of the structure and malformations of the skull and face. Thus, our systematized data on the features of spatio-temporal transformations of morphometric parameters of transverse skull length, face width, skull height, total face height with subsequent construction of mathematical models will contribute to the individualization of the norm, improvement of early diagnosis methods and development of new methods for surgical correction of congenital defects of the skull and face.

Alvarezsaurid osteology: new data on cranial anatomy

ABSTRACT Alvarezsaurs were a group of theropod dinosaurs found in Asia, North America, South America and Europe during Jurassic and Cretaceous periods. In spite of being known by several specimens, diverse aspects of their anatomy remain poorly known. The aim of the present paper is to describe and analyse some points of the neuroanatomy of a newly collected alvarezsaurid specimen. A partial skeleton of an indeterminate Late Cretaceous alvarezsaurid theropod (HGM L08-59) from the collection of Henan Geological Museum in Zhengzhou, China, preserved a partial skull that allows to study some aspects of braincase anatomy. Anatomical features observed in HGM L08-59 and other alvarezsaurs indicate that members of this clade exhibited a notably enhanced somatosensory control during locomotion. The study of skull material of HGM L08-59 as well as that of other alvarezsaur skulls, sheds some doubts on the phylogenetic position of supposed Jurassic alvarezsaurs from China (i.e., Haplocheirus, Aorun and Shishugounykus). Further, some skull features of Haplocheirus are reminiscent to those of ornithomimosaurs and are dissimilar to alvarezsaurs. A comprehensive phylogenetic analysis will shed light on this complex topic that is highly relevant on discussions about early radiation of coelurosaurian theropods.