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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 diametersgt;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.

The cranial casques of modern cassowaries (Casuarius) have long intrigued researchers; however, in-depth studies regarding their morphological variation are scarce. Through visual inspection, it has been recognized that casque variability exists between conspecifics. Understanding casque variation has both evolutionary and ecological importance. Although hypothesized to be targeted by selection, intraspecific casque variation has not been quantified previously. Through a large sample of C. casuarius (n = 103), we compared casque shape (lateral and rostral views) between sexes and between individuals from non-overlapping geographical regions using two-dimensional (2D) geometric morphometrics. We found no statistically significant differences between the casque shape of females and males and few substantial shape differences between individuals from different geographic areas. Much of the intraspecific variation within C. casuarius is due to casque asymmetries (77.5% rightward deviating, 20.7% leftward deviating, and 1.8% non-deviating from the midline; n = 111), which explain the high variability of southern cassowary casque shape, particularly from the rostral aspect. Finally, we discuss how our non-significant findings implicate social selection theory, and we identify the benefits of quantifying such variation for further elucidating casque function(s) and the social biology of cassowaries.

Domestication leads to phenotypic characteristics that have been described to be similar across species. However, this "domestication syndrome" has been subject to debate, related to a lack of evidence for certain characteristics in many species. Here we review diverse literature and provide new data on cranial shape changes due to domestication in the European rabbit (Oryctolagus cuniculus) as a preliminary case study, thus contributing novel evidence to the debate. We quantified cranial shape of 30 wild and domestic rabbits using micro-computed tomography scans and three-dimensional geometric morphometrics. The goal was to test (1) if the domesticates exhibit shorter and broader snouts, smaller teeth, and smaller braincases than their wild counterparts; (2) to what extent allometric scaling is responsible for cranial shape variation; (3) if there is evidence for more variation in the neural crest-derived parts of the cranium compared with those derived of the mesoderm, in accordance with the "neural crest hypothesis." Our own data are consistent with older literature records, suggesting that although there is evidence for some cranial characteristics of the "domestication syndrome" in rabbits, facial length is not reduced. In accordance with the "neural crest hypothesis," we found more shape variation in neural crest versus mesoderm-derived parts of the cranium. Within the domestic group, allometric scaling relationships of the snout, the braincase, and the teeth shed new light on ubiquitous patterns among related taxa. This study-albeit preliminary due to the limited sample size-adds to the growing evidence concerning nonuniform patterns associated with domestication.

From the appearance of the vertebrate head, the trigeminal system has played a role in behavioral and ecological adaptation. The trigeminal nerve is the primary cranial somatosensory nerve, also innervating the jaw muscles. In crocodylians, the trigeminal nerve plays a role in modulating the high bite force and unique integumentary sensation. In association with these behaviors, crocodylians are known for large trigeminal nerves, a high volume of trigeminal-innervated musculature, and densely packed, specialized sensory receptors. These innovations also occurred in concert with a restructuring of the lateral braincase wall. These morphologies have previously been investigated in phylogenetic and evolutionary contexts, but an ontogenetic, whole-system investigation of trigeminal tissue and associated musculature, cartilage, and bone is lacking, as is an understanding of developmental timing of morphologies significant to hypotheses of homology. Here, we use contrast-enhanced computed tomography imaging to provide description and analysis of the trigeminal system in an ontogenetic series of Alligator mississippiensis from embryonic to adult form. We explore growth rates and allometric relationships of structures and discuss the significance to hypotheses of homology. We find a high growth rate and allometric trajectory of the trigeminal nerve in comparison to other cranial nerves, likely associated with the large volume of trigeminal musculature and high densities of sensory receptors. We identify a similar trend in the pterygoideus dorsalis muscle, the highest contributor to bite force. We narrow ontogenetic timing of features related to the trigeminal topological paradigm and the undeveloped epipterygoid. Overall, we provide a basis for understanding trigeminal development in crocodylians, which upon comparison across reptiles will reveal ontogenetic origins of morphological variation.

A number of criteria for the assessment of biological sex, which are applied to living or recently deceased individuals, have been developed, such as genetic, chromosomal, gonadal, hormonal, and phenotypic criteria. Features of a metric and descriptive nature are used to assess the sex of skeletal materials. The diagnostic features of the skull are concentrated in the craniofacial region and around the eye sockets. The mandible is a diagnostically important part of the skull, on which a complex of features is visible. These features develop up to the third decade of life. The goal of the research was to assess the suitability of the parameters of the preangular notch, in other words, the length, height, and surface area for sex prediction applied to skeletal materials. The study included computed tomography images of the masticatory system of 194 patients, consisting of 83 females and 111 males, aged from 16 to 93 years. The three straight lines which correspond to the sides of the triangle representing the notch, in addition to its height, were determined and measured digitally. The receiver operating characteristic method was used to assess the usefulness of the studied features for the purposes of sex prediction. The sensitivity of the test ranged from 51.4% to 67% for the parameters of the preangular notch on the right-hand side, and from 44.4% to 80.2% on the left-hand side. The most reliable predictive models were obtained for two features (shown in the graphical abstract). However, when taking into account, the specificity and sensitivity of the tests presented here, only the length of side AB (a basal length of the notch) can be regarded as a feature that supports the assessment of sex on the basis of other diagnostic features of the mandible. The size and shape of the preangular notch should be treated as auxiliary features in the assessment of sex. For this reason, it is recommended that they should be applied simultaneously to the set of features described in the section on anthropological standards.

This study examined if the cranial measurements from Data Collection Procedures for Forensic Skeletal Material 2.0 are repeatable when measured in dry bones and MSCT images and if the virtual measurements correspond to the physical ones. The sample included 33 dry crania imaged by MSCT. Two observers measured dry bones, two placed landmarks on 2D and 3D MSCT reconstructions, and one conducted measurements/landmarking on both media. One of the observers for each media repeated the measurements. Technical and relative technical error of measurement (TEM and rTEM) and percentage differences were calculated to examine the repeatability of measurements and compare measuring modalities. Intraobserver rTEM was above 1.5% for six bone measurements: FOB, ZOB, OBB, NLH, DKB, MDH (1.51%–4.87%) and for seven MSCT measurements: OBH, FOB, OBB, MDH, NLB, ZOB, DKB (1.57%–5.55%). The interobserver rTEM was above the acceptable level (>2%) for 11 measurements: PAC, NLH, OBB, EKB, MAL, FOB, NLB, OBH, ZOB, DKB, and MDH (2.01%–9.34%). The percentage differences were not systematically larger for measurements taken by the same user on both modalities than those obtained by different users on the same modality. When physical and MSCT measurements were tested on sex classification standards, the proportion of crania classified as male or female did not significantly differ (p > 0.05). The study showed that physical and virtual cranial measurements could be interchangeable for developing or applying sex estimation standards. However, clarifications and adaptations are necessary for measurements of mastoid, nasal, and orbital regions that did not meet the standard criteria.

The aim of this study was to evaluate the in vivo performance of two different deproteinized bovine bone (DBB) grafting materials: DBBB (Bio-Oss®) and DBBL (Laddec®), for the regeneration of critically sized (8 mm) defects in rabbit's calvaria. Three round-shaped defects were surgically created in the calvaria of 13 New Zealand White rabbits proximal to the coronal suture in the parietal bone. Two of the defects were filled with one of the grafting materials while a third was left empty to serve as a negative control. Bone regeneration properties were evaluated at 4- and 8-weeks after implantation by means of histological and histomorphometrical analyses. Statistical analyses were performed through a mixed model analysis with fixed factors of time and material. Histological evaluation of the control group evidenced a lack of bridging bone formation across the defect sites at both evaluation time points. For the experimental groups, new bone formation was observed around the defect periphery and to progress radially inwards to the center of the defect site, regardless of the grafting material. Histomorphometric analyses at 4 weeks demonstrated higher amount of bone formation through the defect for DBBB group. However, at 8 weeks, DBBL and DBBB demonstrated osteoconductivity and low resorption rates with evidence of statistically similar bone regeneration through the complete boney defect. Finally, DBBB presented lower soft tissue migration within the defect when compared to DBBL at both evaluation time points. DBBB and DBBL presented similar bone regeneration performance and slow resorption rates. Although both materials promoted bone regeneration through the complete defect, DBBB presented lower soft tissue migration within the defects at 4- and 8-weeks.

Magnetic resonance imaging (MRI) is increasingly utilized as a radiation-free alternative to computed tomography (CT) for the diagnosis and treatment planning of musculoskeletal pathologies. MR imaging of hard tissues such as cortical bone remains challenging due to their low proton density and short transverse relaxation times, rendering bone tissues as nonspecific low signal structures on MR images obtained from most sequences. Developments in MR image acquisition and post-processing have opened the path for enhanced MR-based bone visualization aiming to provide a CT-like contrast and, as such, ease clinical interpretation. The purpose of this review is to provide an overview of studies comparing MR and CT imaging for diagnostic and treatment planning purposes in orthopedic care, with a special focus on selective bone visualization, bone segmentation, and three-dimensional (3D) modeling. This review discusses conventional gradient-echo derived techniques as well as dedicated short echo time acquisition techniques and post-processing techniques, including the generation of synthetic CT, in the context of 3D and specific bone visualization. Based on the reviewed literature, it may be concluded that the recent developments in MRI-based bone visualization are promising. MRI alone provides valuable information on both bone and soft tissues for a broad range of applications including diagnostics, 3D modeling, and treatment planning in multiple anatomical regions, including the skull, spine, shoulder, pelvis, and long bones. LEVEL OF EVIDENCE: 3 TECHNICAL EFFICACY: Stage 3.

CT is routinely used to detect cranial abnormalities in pediatric patients with head trauma or craniosynostosis. This study aimed to develop a deep learning method to synthesize pseudo-CT (pCT) images for MR high-resolution pediatric cranial bone imaging to eliminating ionizing radiation from CT.3D golden-angle stack-of-stars MRI were obtained from 44 pediatric participants. Two patch-based residual UNets were trained using paired MR and CT patches randomly selected from the whole head (NetWH) or in the vicinity of bone, fractures/sutures, or air (NetBA) to synthesize pCT. A third residual UNet was trained to generate a binary brain mask using only MRI. The pCT images from NetWH (pCTpCTMR high-resolution pediatric cranial bone imaging may facilitate the clinical translation of a radiation-free MR cranial bone imaging method for pediatric patients.

The process by which upper respiratory tract structures have changed over deep evolutionary time is, in part, reflected in the process of embryologic development. The nasopharynx in particular is a centrally located space bounded by components of the respiratory portion of the nasal cavity, cranial base, soft palate, and Eustachian tube. The development of these components can be understood both in terms of embryologic structures such as the branchial arches and paraxial mesoderm and through fossil evidence dating as far back as the earliest agnathan fish of the Cambrian Period. Understanding both the evolution and development of these structures has been an immeasurable benefit to the otolaryngologist seeking to model disease etiology of both common and rare conditions. This discussion is a primer for those who may be unfamiliar with the central importance of the nasopharynx both in terms of our evolutionary history and early embryological development of vital cranial and upper respiratory tract structures.

Major cell-to-cell signaling pathways, such as the fibroblast growth factors and their four receptors (FGF/FGFR), are conserved across a variety of animal forms. FGF/FGFRs are necessary to produce several "vertebrate-specific" structures, including the vertebrate head. Here, we examine the effects of the FGFR2 S252W mutation associated with Apert syndrome on patterns of cranial integration. Our data comprise micro-computed tomography images of newborn mouse skulls, bred to express the Fgfr2 S252W mutation exclusively in either neural crest or mesoderm-derived tissues, and mice that express the Fgfr2 S252W mutation ubiquitously.Procrustes-based methods and partial least squares analysis were used to analyze craniofacial integration patterns. We found that deviations in the direction and degree of integrated shape change across the mouse models used in our study were potentially driven by the modular variation generated by differing expression of the Fgfr2 mutation in cranial tissues.Our overall results demonstrate that covariation patterns can be biased by the spatial distribution and magnitude of variation produced by underlying developmental-genetic mechanisms that often impact the phenotype in disproportionate ways.

To study morphological evolution, it is necessary to combine information from multiple intersecting research fields. Here, we report on the structure of the bony and muscular elements of the craniomandibular complex of birds, highlighting its morphological architecture and complexity (or simplification) in the context of anatomical networks of the Band-winged Nightjar Systellura longirostris (Caprimulgiformes, Caprimulgidae). This species has skull osteology and jaw myology that departs from the general structural plan of the craniomandibular complex of Neornithes and is considered morphologically simple. Our goal is to test if its simplification is also reflected in its anatomical network, particularly in those parameters that measure complexity and to explore if the distribution of the networks in a phylomorphospace is conditioned by their evolutionary history or by convergence. Our results show that S. longirostris clusters with other Strisores and momotids and is segregated from the other bird species analyzed when plotted in the phylomorphospace, as a consequence of convergence in the network parameters. Systellura has a craniomandibular complex consisting of fewer muscles connecting more bones than the model species (e.g., the rock pigeon or the guira cuckoo). In this sense, Systellura is actually more complex regarding the number of integrative bony parts, while its craniomandibular complex is simpler. According to its anatomical network, Systellura also can be interpreted as less complex, particularly compared with other Strisores and taxa that reflect the general structure of the craniomandibular complex in Neornithes.

This contribution focuses on a 1928 multiauthor paper reporting the discovery of a child's skull at Devil's Tower cave on the Rock of Gibraltar. It was ground-breaking. Two of the lead authors, Dorothy Garrod and Dorothea Bate, were women, and it was one of the earliest reports of a fossil hominin to incorporate and integrate detailed information about its stratigraphic and environmental context.

The classical anatomist Drew Noden spearheaded craniofacial research, laying the foundation for our modern molecular understanding of development, evolution, and disorders of the craniofacial skeleton. His work revealed the origin of cephalic musculature and the role of cranial neural crest (CNC) in early formation and patterning of the head musculoskeletal structures. Much of modern cranial tendon research advances a foundation of knowledge that Noden built using classical quail-chick transplantation experiments. This elegant avian chimeric system involves grafting of donor quail cells into host chick embryos to identify the cell types they can form and their interactions with the surrounding tissues. In this review, we will give a brief background of vertebrate head formation and the impact of CNC on the patterning, development, and evolution of the head musculoskeletal attachments. Using the zebrafish as a model system, we will discuss examples of modifications of craniofacial structures in evolution with a special focus on the role of tendon and ligaments. Lastly, we will discuss pathologies in craniofacial tendons and the importance of understanding the molecular and cellular dynamics during craniofacial tendon development in human disease.

Brain and skull tissues interact through molecular signalling and mechanical forces during head development, leading to a strong correlation between the neurocranium and the external brain surface. Therefore, when brain tissue is unavailable, neurocranial endocasts are often used to approximate brain size and shape. Evolutionary changes in brain morphology may have resulted in secondary changes to neurocranial morphology, but the developmental and genetic processes underlying this relationship are not well understood. Using automated phenotyping methods, we quantified the genetic basis of endocast variation across large genetically varied populations of laboratory mice in two ways: (1) to determine the contributions of various genetic factors to neurocranial form and (2) to help clarify whether a neurocranial variation is based on genetic variation that primarily impacts bone development or on genetic variation that primarily impacts brain development, leading to secondary changes in bone morphology. Our results indicate that endocast size is highly heritable and is primarily determined by additive genetic factors. In addition, a non-additive inbreeding effect led to founder strains with lower neurocranial size, but relatively large brains compared to skull size; suggesting stronger canalization of brain size and/or a general allometric effect. Within an outbred sample of mice, we identified a locus on mouse chromosome 1 that is significantly associated with variation in several positively correlated endocast size measures. Because the protein-coding genes at this locus have been previously associated with brain development and not with bone development, we propose that genetic variation at this locus leads primarily to variation in brain volume that secondarily leads to changes in neurocranial globularity. We identify a strain-specific missense mutation within Akt3 that is a strong causal candidate for this genetic effect. Whilst it is not appropriate to generalize our hypothesis for this single locus to all other loci that also contribute to the complex trait of neurocranial skull morphology, our results further reveal the genetic basis of neurocranial variation and highlight the importance of the mechanical influence of brain growth in determining skull morphology.

Currently, there is no consensus whether there is a single or multiple postnatal stem cell population(s) that contribute to skeletal homeostasis and post-natal bone formation. A known population of cells that express Prx1 contributes to post-natal bone formation. Prx1 expression also connotes calvaria and appendicular tissues during embryonic development. A transgenic tamoxifen inducible Prx1 reporter mouse was used for lineage tracking, to characterize the post-natal contribution of Prx1 expressing cells in skeletal homeostasis and bone formation. Under homeostatic conditions Prx1 labeling gave rise to a transient yet rapid turnover cell population at the periosteal and endosteal surfaces, along muscle fibers, and within the medial layers of vessels both within the muscle and marrow compartments of the appendicular skeleton. Fracture and ectopic bone formation of both fore and hind limbs showed recruitment and expansion of Prx1-derived cells in newly formed bone tissues. Prx1 labeled cells were limited or absent at axial skeletal sites during both homeostasis and after induction of bone formation. Lastly, Prx1-derived cells differentiated into multiple cell lineages including vascular smooth muscle, adipose, cartilage, and bone cells. These results show that Prx1 expression retained its embryonic tissue specification and connotes a stem/progenitor cell populations of mesenchymal tissue progenitors.

Xenopus laevis is a widely used model organism in the fields of genetics and development, and more recently evolution. At present, the most widely used staging table for X. laevis is based primarily on external features and does not describe the corresponding skull development in detail. Here, we describe skull development in X. laevis, complete with labeled figures, for each relevant stage in the most widely used staging table.We find skull development in X. laevis is, for the most part, distinct at each of the previously established stages based on external anatomy. However, variation does exist in the timing of onset of ossification of certain bones in the skull, which results in a range of stages where a skull element first ossifies. The overall sequence of ossification is less variable than the timing of ossification onset.While events in skull development vary somewhat between specimens, and in comparison, to external events, this staging table is useful in showing both when bones first appear and for documenting the range of temporal variance in X. laevis skull development more accurately than previously done. Furthermore, when only skull data are available, the approximate stage of a specimen can now be determined.

BACKGROUND: Absence of Golgi microtubule-associated protein 210 (GMAP210), encoded by the TRIP11 gene, results in achondrogenesis. Although TRIP11 is thought to be specifically required for chondrogenesis, human fetuses with the mutation of TRIP11 also display bony skull defects where chondrocytes are usually not present. This raises an important question of how TRIP11 functions in bony skull development. RESULTS: We disrupted Trip11 in neural crest-derived cell populations, which are critical for developing skull in mice. In Trip11 mutant skulls, expression levels of ER stress markers were increased compared to controls. Morphological analysis of electron microscopy data revealed swollen ER in Trip11 mutant skulls. Unexpectedly, we also found that Golgi stress increased in Trip11 mutant skulls, suggesting that both ER and Golgi stress-induced cell death may lead to osteopenia-like phenotypes in Trip11 mutant skulls. These data suggest that Trip11 plays pivotal roles in the regulation of ER and Golgi stress, which are critical for osteogenic cell survival. CONCLUSION: We have recently reported that the molecular complex of ciliary protein and GMAP210 is required for collagen trafficking. In this paper, we further characterized the important role of Trip11 being possibly involved in the regulation of ER and Golgi stress during skull development.

The temporomandibular joint is the direct interface between the mandible and the cranium and is critical for transmitting joint reaction forces and determining mandibular range of motion. As a consequence, understanding variation in the morphology of this joint and how it relates to other aspects of craniofacial form is important for better understanding masticatory function. Here, we present a detailed three-dimensional (3D) geometric morphometric analysis of the cranial component of this joint, the glenoid fossa, across a sample of 17 anthropoid primates, and we evaluate covariation between the glenoid and the cranium and mandible. We find high levels of intraspecific variation in glenoid shape that is likely linked to sexual dimorphism and joint remodeling, and we identify differences in mean glenoid shape across taxonomic groups and in relation to size. Analyses of covariation reveal strong relationships between glenoid shape and a variety of aspects of cranial and mandibular form. Our findings suggest that intraspecific variation in glenoid shape in primates could further be reflective of high levels of functional flexibility in the masticatory apparatus, as has also been suggested for primate jaw kinematics and muscle activation patterns. Conversely, interspecific differences likely reflect larger scale differences between species in body size and/or masticatory function. Results of the covariation analyses dovetail with those examining covariation in the cranium of canids and may be indicative of larger patterns across mammals.

Morphological data sets are misleading in salamander (Caudata) phylogeny due to the relative homoplasy of the dermal skull observed in paedomorphic forms, leading to the trend of excluding morphology when exploring questions of salamander phylogeny. Investigations in caecilians (Gymnophiona) have demonstrated that the inclusion of braincase morphology can rescue morphological phylogenetic analyses and produce topologies congruent with molecular data sets. We scanned 28 species (25 genera) of salamander, representing all 10 families, with high-resolution micro-computed tomography to investigate braincase variation. We describe the morphology of the braincase for all 10 families and distinguish between paedomorphic and metamorphic morphologies. Our results demonstrate a general uniformity amongst metamorphic species with variation largely restricted to the occipito-otic region. A greater range of variation is observed within paedomorphic forms than would be expected when considering the homoplasy of the dermal skull. Obligate paedomorphic forms demonstrate considerably more variation in the anterior braincase than do facultative paedomorphs, which we suggest is evidence of a greater complexity in the evolution and development of these forms than neoteny alone would produce. This raises the question of character independence within morphological data sets and warrants further investigation into the correlation of other characters before morphological data are omitted.

In several taxa of Neornithes (crown group birds), the lacrimal/ectethmoid complex exhibits small bones, the comparative osteology of which is poorly studied. Some of these ossicles-which are commonly known as uncinate bones (ossa uncinata or ossa lacrimopalatina)-were already described two centuries ago, but knowledge of their distribution and morphological variability in higher level clades is incomplete. In the present study, a detailed survey of the occurrence of uncinate bones is given, and these ossicles are for the first time reported in the gruiform Psophiidae, some Rallidae, and in the Otidiformes. Their presence in the latter taxon is of particular interest, because in current molecular analyses, the Otidiformes result as close relatives of the Musophagiformes, in which the uncinate bone is particularly large. The uncinate bones of most other neornithine clades, however, appear to have evolved multiple times independently through parallel evolution from the same ligamentous structures. A few earlier authors assumed that the uncinate bone is homologous to the ectopterygoid of non-avian theropods. Although this remains a viable hypothesis, more data on the occurrence of the ectopterygoid in Mesozoic birds are needed for well-supported conclusions. Here, it is noted that the ontogenetic development of the uncinate bone appears to be correlated with that of the ectethmoid, which is another bone in the skull of neornithine birds that is of unknown origin.

How developing brains mechanically interact with the surrounding embryonic scalp layers (ie, epidermal and mesenchymal) in the preosteogenic head remains unknown. Between embryonic day (E) 11 and E13 in mice, before ossification starts in the skull vault, the angle between the pons and the medulla decreases, raising the possibility that when the elastic scalp is directly pushed outward by the growing brain and thus stretched, it recoils inward in response, thereby confining and folding the brain.Stress-release tests showed that the E11-13 scalp recoiled and that the in vivo prestretch prerequisite for this recoil was physically dependent on the brain (pressurization at 77-93 Pa) and on actomyosin and elastin within the scalp. In scalp-removed heads, brainstem folding was reduced, and the spreading of ink from the lateral ventricle to the spinal cord that occurred in scalp-intact embryos (with5 μL injection) was lost, suggesting roles of the embryonic scalp in brain morphogenesis and cerebrospinal fluid homeostasis. Under nonstretched conditions, scalp cell proliferation declined, while the restretching of the shrunken scalp rescued scalp cell proliferation.In the embryonic mouse head before ossification, a stretcher-compressor relationship elastically develops between the brain and the scalp, underlying their mechanically interdependent development.

The fibroblast growth factor (FGF)/FGF receptor (FGFR) signaling pathway plays important roles in the development and growth of the skeleton. Apert syndrome caused by gain-of-function mutations of FGFR2 results in aberrant phenotypes of the skull, midface, and limbs. Although short limbs are representative features in patients with Apert syndrome, the causative mechanism for this limb defect has not been elucidated. Here we quantitatively confirmed decreases in the bone length, bone mineral density, and bone thickness in the Apert syndrome model of gene knock-in Fgfr2

To determine whether collagen membrane (CM) fixation enhances guided bone regeneration in standardized defects.Four 8-mm-diameter defects were surgically made in eight rabbit calvaria, and randomly allocated into four groups: control (empty), unfixed-CM, fixed-CM, and unfixed-CM with bone graft (BG + CM) (positive control). After 1- and 4-week healing periods, the animals were sacrificed and quantitative reverse transcription polymerase chain reaction, micro-computed tomography, and histological outcomes were assessed.At week 1, the expression levels of BMP-2, FGF-2, VEGF, and osteocalcin were significantly higher in the fixed-CM group than in the unfixed-CM and control groups (p .05). Conversely, cathepsin-K was significantly expressed in the unfixed-CM group. No significant differences in expression markers were observed between the fixed-CM and BG + CM groups (p .05). At week 4, new bone formation was significantly higher in the fixed-CM group than the unfixed-CM and control groups (p .05), but similar to the BG + CM group (p .05).CM fixation enhances the expression of osteogenic factors similar to BG + CM, leading to significantly more new bone formation. This suggests that the osteogenic potential is greater when membranes are fixed, thereby limiting the necessity of membrane-supporting materials to enhance bone formation.

Irajatherium hernandezi is a poorly known non-mammaliaform cynodont from the Late Triassic of southern Brazil. A new specimen of this cynodont was found in recent fieldwork to the type-locality, Sesmaria do Pinhal (Candelária), providing new insights into the anatomy of this mammalian forerunner. This specimen comprises a partial skull preserving the left canine, two left and three right postcanines, and an isolated exoccipital; the left dentary with the canine and postcanines; a fragment of the right dentary; the proximal portion of the left partial humerus; the right scapula; and indeterminate fragments. Based on new material, it is here suggested that I. hernandezi presents: a rostrum broad and short, possibly long as the temporal region; three foramina on the lateral surface of the maxilla, that could correspond to the external openings of the rostral alveolar, infraorbital, and zygomaticofacial canals; a slender zygomatic arch and an absent postorbital bar; a posteriorly wide temporal fossa; a long secondary palate, slightly surpassing the level of the last postcanine tooth; the cerebral hemispheres of the cranial endocast divided by a median sulcus; the scapular blade long and straight, and the postscapular fossa absent in lateral aspect. Finally, I. hernandezi and other tritheledontids were included in a phylogenetic analysis of Eucynodontia. The analysis recovered unresolved relationships for ictidosaurs/tritheledontids, nested within a polytomy with Tritylodontidae and a clade composed by Pseudotherium argentinus, Botucaraitherium belarminoi, Brasilodon quadrangularis, and Mammaliaformes.

Made available in DSpace on 2022-04-29T08:36:56Z (GMT). No. of bitstreams: 0 Previous issue date: 2022-01-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) This study aimed to perform quantitative and qualitative evaluations of the lateral and third ventricles, and brain parenchyma, in healthy dogs of different skull conformations on CT scans. Forty-five adult client-owned dogs were divided into three groups according to skull conformation: G1 (dolichocephalic)—15 German Shepherds; G2 (mesaticephalic)—15 Rottweilers; G3 (brachycephalic)—15 Boxers. Transverse plane images were used for quantitative and qualitative evaluations of the lateral ventricles and third ventricle, and pre- and post-contrast brain parenchyma. The height of both ventricles and brain was measured at the level of the interthalamic adhesion. Ventricle height, brain height, and ventricle/brain height ratio were statistically higher in G3 compared with G1 and G2 that were similar. The third ventricle was visible but unmeasurable in five dogs from G1 and three from G2. In G3, all dogs had third ventricle visible and measurable in all images. Asymmetric ventricles were seen in five dogs in Group 1 and Group 2, and seven in Group 3. Brain parenchyma had homogenous density in 80% of the dogs in all groups. Contrast enhancement of the rostral midline was visualized in all dogs. In conclusion, brain CT scans of healthy dogs showed that the qualitative data were similar among groups, but lateral ventricle and brain measurements in brachycephalic dogs differed from the dolichocephalic and mesaticephalic dogs. Department of Animal Reproduction and Veterinary Surgery School of Veterinary Medicine and Animal Science—São Paulo State University (UNESP) Department of Animal Reproduction and Veterinary Surgery School of Veterinary Medicine and Animal Science—São Paulo State University (UNESP) FAPESP: 09/06899-0

Purpose To investigate the oncological outcomes of orbital malignant tumors invading the skull base. Methods A retrospective analysis was conducted on 16 patients with orbital malignant tumors invading the skull base. Eleven patients were treated with skull base surgery, four patients were treated with particle therapies, and one patient was treated with chemoradiotherapy (CRT) as initial treatment. Results The most frequent histological type was adenoid cystic carcinoma in seven patients, followed by squamous cell carcinoma in two patients. Local recurrence occurred in two of the six surgically treated patients who did not receive postoperative radiotherapy (RT) or CRT. One of them was successfully salvaged by RT, and the other died of disease. With a median follow‐up of 24 months, the 2‐year overall, local control, and disease‐free survival rates of all patients were 82.5%, 87.5%, and 59%, respectively. Conclusions Patients with positive surgical margins were at risk of local recurrence. Postoperative RT should be considered for all surgically treated patients. Level of Evidence: 4.

The globally distributed extinct clade Enantiornithes comprises the most diverse early radiation of birds in the Mesozoic with species exhibiting a wide range of body sizes, morphologies, and ecologies. The fossil of a new enantiornithine bird, Brevirostruavis macrohyoideus gen. et sp. nov., from the Lower Cretaceous Jiufotang Formation in Liaoning Province, northeastern China, preserves a few important skeletal features previously unknown among early stem and extant birds, including an extremely elongate bony hyoid element (only slightly shorter than the skull), combined with a short cranial rostrum. The long hyoid provides direct evidence for the evolution of specialized feeding in this extinct species, and appears similar to the highly mobile tongue that is mobilized by the paired epibranchials present in living hummingbirds, honeyeaters, and woodpeckers. The likely linkage between food acquisition and tongue protrusion might have been a key factor in the independent evolution of particularly elongate hyobranchials in early birds.