Journal of Anatomy最新文献

Mammalian tendons, including human tendons, possess limited regeneration capability, and its healing results in scar tissue formation. However, it was recently shown that tendons of newts, amphibians that exhibit regeneration capacity in various tissues and organs, achieve full regeneration, structurally and functionally, following complete transection. The present study was performed to characterize newt tendon regeneration structurally at both micro- and nanoscales following transection surgery. In particular, we observed the progress of tendon regeneration in the same newt by developing a unique, live, in vivo imaging technique. Initial cell infiltration and formation of granulation-like tissue were evident between residual tendon stubs during the first week of regeneration. This newly formed tissue bridged tendon stubs by 3 weeks. This was followed by remodeling of the initial matrix to new tendon from the 6th to 12th week, during which the mechanical properties of regenerated tendon reached levels equivalent to those of normal tendons. These microscopic structural changes were associated with ultrastructural maturation. Collagen fibril density and fibril area fraction at the nanoscale were significantly improved from the 3rd to 6th week, and fibril area fraction at the microscale was significantly improved from 6 to 12 weeks. Such changes were not observed in a mouse model. These experimental findings suggest that newt tendon regeneration can be divided into two phases: the early phase (<6 weeks) and the late phase (≥6 weeks). The early phase involves an initial response to tendon transection, such as bleeding, accumulation of initial extracellular matrix, and an increase in the cell population at the transection site, leading to re-connection of transected tendon stubs, whereas the late phase is dedicated to maturation of regenerated collagenous tissue into new tendon. This is the first study to reveal structural mechanisms of newt tendon regeneration following transection. It warrants further study to explore molecular mechanisms that might achieve such regeneration in mammalian tendon.

Suture shape and complexity are thought to influence skull function in mammals, supporting the evolution of ecological and morphological diversity. These aspects of suture morphology are seldom studied in a comparative context, especially relative to the multitude of comparative studies of cranial shape. Using a three-dimensional comparative ontogenetic dataset spanning 22 species across the phylogenetic breadth of Mammalia and sampling from foetal to adult stages, we applied 3D geometric morphometrics and 2D complexity metrics to track the evolutionary and developmental morphology of three cranial sutures (interfrontal, sagittal and coronal). Shape and complexity vary across the three sutures, with complexity decreasing through ontogenetic stages for antero-posterior sutures (interfrontal and sagittal) but showing a postnatal increase for transversal sutures (the coronal). This suggests that aging is the strongest influence on longitudinal suture complexity because of simplification and obliteration for sutures subject to tensile stresses. This adulthood trend can be explained by a necessity to consolidate the skull through fusion, coupled with the disappearing need to accommodate further brain growth. Transversally positioned sutures oppose the trend as they are subject to the compressive stresses of cranial mechanics. Additionally, our findings refute the hypothesis that placental mammals have more complex and variable sutures than marsupials reflecting their more disparate ecologies. Rather, developmental history was found to be the greatest influence on suture complexity and variability. As a result, the extreme altriciality of marsupials, and its related longer postnatal brain growth, allows them to match and surpass the suture variability found in most placentals, reaching levels otherwise found mainly in primates.

The Journal of Anatomy Early Career Researcher Workshop took place on a bright and breezy Monday lunchtime in the picturesque grounds of St. John's College, University of Oxford, as part of the Anatomical Society's Summer Meeting. The event brought together a diverse audience of nearly 70 attendees spanning a wide range of career stages: postgraduate students (29%), postdoctoral researchers and teaching fellows (14%), lecturers and assistant professors (21%), senior lecturers, readers and professors (29%), as well as others (7%).

The workshop was led by Journal of Anatomy Co-Editor-in-Chief James Sleigh alongside members of the journal's Early Career Researcher (ECR) Board; Alannah Mole and Hazel Allardyce, together with Editorial Board member and recent Special Issue Guest Editor, Sourav Bhattacharjee.

James Sleigh shares expert guidance on crafting strong research articles and navigating the publication process for success.

Building on this, Hazel and Alannah provided an Early Career perspective on the publishing process, walking the audience through the full journey of a manuscript—from initial submission to editorial decisions and peer review. Their insights into the motivations and expectations surrounding journal reviewing were particularly helpful for those new to the process, and they underscored the importance of becoming a constructive reviewer as part of professional development in academia. As Sourav commented in his subsequent talk: “Being a referee has made me a better author”.

Members of the Journal of Anatomy editorial team who led the Early Career Researcher workshop. From left to right: Alannah Mole, Hazel Allardyce, Sourav Bhattacharjee, and James Sleigh.

We are grateful to all of our Journal of Anatomy editorial board members for making the workshop successful. Sincere thanks to Hannah Webb, Gavin Clowry, and Zoltán Molnár for their support in organising the event, and to Kerry Edwards at Wiley for her help with promotion and marketing.

The Journal of Anatomy remains committed to supporting Early Career Researchers through opportunities like these. We look forward to continuing this dialogue and sharing our collective expertise to support the next generation of anatomical scientists.

The Journal of Anatomy also remains committed to supporting the wider anatomical research community through collaborative peer review. We are always keen to welcome new reviewers who are enthusiastic about contributing to the journal's mission and supporting fellow researchers.

The peripheral nervous system has been the subject of various studies on topics ranging from the innervation of tissues and organs to central nervous system clearance and neuropathies. Because research methods are mainly based on dissection techniques accompanied by histological studies, they inevitably lead to the destruction of the tissue under study. Our team has developed a method consisting of injecting peripheral nerves with barium contrast that can be visualized with computed tomography (CT) scans. We infused unfixed specimens of the vertebral column with contrast agent, subsequently scanned them via a CT system, and finally created three-dimensional models, which included the spinal nerves (including the ganglia, the communicating branches, and the rami of the spinal nerve), the intercostal nerves, the plexuses (brachial, lumbar, and sacral) and the sympathetic trunk. The obtained spatial models are characterized by high didactic values and can be used for academic and postgraduate purposes (e.g., teaching medical students, planning peripheral nerve blocks, analysis of zygapophysial joints innervation). The method leaves the samples intact and facilitates further analyses by allowing noninvasive selection of areas of interest (e.g., targeted dissection, histological studies, and micro-CT). We provide a step-by-step description of this method, including injecting the peripheral nerves and subsequently obtaining three-dimensional models.

Research on brain evolution centres mainly on internal mouldings of the skull, known as endocasts; however, the relationship between the size and asymmetry of the brain and endocasts has been poorly investigated in humans. Therefore, the main objective of this study was to investigate whether endocasts can be reliable indicators of brain size and asymmetry. Magnetic Resonance Imaging (MRI) of 75 participants was used to calculate the volume and surface area of the brain, the endocast, and their respective hemispheres. Two asymmetry indices (i.e. directional and absolute asymmetry) were used to assess the differences in volume and surface area between the sides of the brain and endocast. The Pearson correlation coefficient was calculated to assess the relationships between the parameters, and a Monte Carlo simulation for linear regression was performed to generate prediction equations for brain volume. The relationships between the level and direction of asymmetry indices were investigated using the Pearson correlation and McNemar's test, respectively. All correlations were statistically significant; however, correlation coefficients between volumes were stronger (0.894–0.931) than between volumes and surface areas (0.783–0.834). Brain volume can be predicted with high accuracy (ranging between 0.80 and 0.87) using the endocast total volume or the volume of one of the sides. The associations between the levels of asymmetry indices of the brain and endocast were non-significant; however, the McNemar's test indicated that endocasts show the same left- or right-biased asymmetry as the brain. This was the first study conducted on a large sample of brain and endocast data from the same individuals. The results demonstrated that brain volume can be accurately reconstructed using the volume of the endocast or one of its sides. This finding is especially important in the context of reconstructing fossil skulls, which are usually fragmented. Conversely, the asymmetry levels of endocast parameters are not reliable indicators of the actual level of brain volume asymmetry. Future research on fossils should focus on endocast asymmetry direction (left- or right-biased) as this closely corresponds with brain lateralisation.

Leporid lagomorphs, the rabbits and hares, exhibit unique cranial traits that distinguish them from their closest relatives, the Ochotonidae (pikas), and all other mammals. Among these features, the intracranial joint stands out as the only example of cranial kinesis in mammals and is hypothesised to dissipate kinetic energy during high-speed locomotion. Despite its potential functional importance, the morphology of the joint remains understudied. High complexity in other cranial sutures has been associated with behavioural traits such as feeding and head butting. In this study, we quantified the complexity of the intracranial joint using two independent metrics and explored its relationships with overall cranial shape, locomotor mode, cranial size and body mass, burrowing habit, and facial tilt angle. We found significant correlations between complexity and locomotor mode as well as with facial tilt angle, indicating that cursorial species have less complex sutures and highlighting a potential link between the complexity of suture interdigitation and facial tilting. However, complexity did not correlate with size or burrowing habit. Our findings shed more light on the functional anatomy of the leporid cranium and emphasise the need for further research on ontogenetic development, biomechanics, and behaviour to fully understand the evolutionary and functional significance of these unique cranial traits.

Although the existence of postcranial pneumaticity and the inferred presence of air sacs connected to the lungs are well established in Pterosauria, the origin of this system in pterosaurs remains unclear. We investigated skeletal pneumaticity in the Triassic pterosauromorph Venetoraptor using microcomputed tomography, seeking insights into the origin of postcranial pneumaticity. Our analysis reveals distinct patterns of postcranial pneumaticity, providing insights into the evolution of the respiratory adaptations of pterosauromorpha. Venetoraptor exhibits a mosaic of pneumatic foramina and internal chambers in its vertebrae, suggesting the early evolution of an elaborate system of air sacs connected to the lungs, which suggests the presence of an elaborate respiratory system. These findings support the hypothesis that invasive air sacs predated true pterosaurs, providing advantages such as enhanced ventilatory efficiency, reduced skeletal mass, and increased mechanical strength, all crucial for powered flight. Our study underscores the significance of early pneumatic structures in shaping vertebrate flight evolution, positioning pterosauromorphs as one of the key intermediary lineages in the development of avian-style respiratory systems.

The sacroiliac articulation in anurans enables locomotion, including burrowing, swimming, jumping, and walking, by facilitating pelvic rotation and sliding. The hylid tribe Scinaxini comprises 134 Neotropical treefrogs divided into three genera: Julianus, Ololygon, and Scinax. The osteological elements of the sacroiliac articulation are well studied within the tribe, with Julianus having distinctive sacral diapophyses and sesamoids. Notably, the species J. camposseabrai has a medially elongated sesamoid, about three times its width in length, along with a short sacral diapophysis-a unique combination among anurans. However, information on the associated musculature in the tribe remains limited, restricting our understanding of this unique morphology. This knowledge gap prompted a detailed investigation of the musculature of the sacroiliac articulation in this clade of treefrogs. We revisited the osteology of the sacroiliac articulation and described its muscles in nine species of Scinaxini, including J. camposseabrai and J. pinimus. Our results showed that the origin and insertion of the muscles are largely conserved across the tribe, but variations exist in the orientation of the m. coccygeosacralis and the degree of separation between slips of the m. iliolumbaris. The species of Julianus have a unique sacroiliac osteo-muscular configuration, particularly J. camposseabrai, which is distinct from any previously described in anurans.

Some aesthetic medicine procedures, such as hyaluronic acid injections and thread implantations, are performed in the forehead area. Therefore, knowledge of the anatomy of this region is essential to ensure that medical procedures are carried out safely. A cross-sectional analysis of the available literature aims to organize and expand knowledge among specialists. Databases, such as Scopus, Embase, Web of Science, and PubMed were used to conduct a literature review, resulting in 1007 publications. After applying exclusion and inclusion criteria, results from 11 articles were extracted. The supratrochlear vein originates at the medial corner of the eye, where it joins the supraorbital vein to form the angular vein. The supraorbital vein, together with the angular vein, drains into the superior ophthalmic vein, converging at the medial edge of the supraorbital margin. Its main trunk connects medially with the supratrochlear veins and laterally with the superficial temporal veins, forming the transverse supraorbital vein. The superficial temporal veins are located on the temporal fascia and may appear as a single main branch or with three terminal branches, according to different reports. The vascularization of the forehead exhibits significant anatomical variability. Therefore, specialists performing medical procedures in this region should be prepared for diverse anatomy to ensure the safe administration of treatments in the forehead area. It is particularly crucial to recognize that pulmonary embolism may be the most serious venous complication following hyaluronic acid-based procedures, underscoring the need for precise anatomical knowledge and procedural caution.