Journal of Anatomy最新文献

{"title":"QuPath Edu and OpenMicroanatomy: Open-source virtual microscopy tools for medical education.","authors":"Aaron Yli-Hallila, Peter Bankhead, Mark J Arends, Petri Lehenkari, Sanna Palosaari","doi":"10.1111/joa.14172","DOIUrl":"10.1111/joa.14172","url":null,"abstract":"<p><p>Virtual microscopy is becoming increasingly common in both medical education and routine clinical practice. Virtual microscopy software is typically designed either for (1) training students in anatomy, histology, and histopathology, or (2) quantitative analysis-but not both simultaneously. QuPath is one of the most widely used software applications for histopathology image analysis in research and provides a comprehensive set of computational tools to evaluate histology slides. We have enhanced QuPath by developing a new extension, QuPath Edu, which adapts the software to function as an intuitive microanatomy learning environment. Additionally, we have created an entirely new, complementary software platform called OpenMicroanatomy, which provides an alternative way to access QuPath Edu teaching content through a web interface. These tools have been used in teaching of first year medical and dentistry students at the University of Oulu Medical Faculty, and we conducted a user survey for the Class of 2023 to assess the usability and student experience. In general, the introduced annotation and quiz features were appreciated by the students and the system usability of OpenMicroanatomy was considered excellent (SUS score 84.8). Together, these freely available tools enable teachers to develop and deploy innovative training material for anatomy, histopathology, quantitative analysis, and artificial intelligence in a wide range of contexts. This unique combination can provide the next generation of students with essential multidisciplinary skills.</p>","PeriodicalId":14971,"journal":{"name":"Journal of Anatomy","volume":" ","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142647707","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Physical constraints on the positions and dimensions of the zebrafish swim bladder by surrounding bones.","authors":"Koumi Satoh, Akiteru Maeno, Urara Adachi, Mizuki Ishizaka, Kazuya Yamada, Rina Koita, Hidemichi Nakazawa, Sae Oikawa, Renka Fujii, Hiroyuki Furudate, Akinori Kawamura","doi":"10.1111/joa.14179","DOIUrl":"https://doi.org/10.1111/joa.14179","url":null,"abstract":"<p><p>Precise regulation of organ size and position is crucial for optimal organ function. Since the swim bladder is primarily responsible for buoyancy in teleosts, early development and subsequent inflation of the swim bladder should be appropriately controlled with the body growth. However, the underlying mechanism remains unclear. In this study, we show that the size and position of the swim bladder are physically constrained by the surrounding bones in zebrafish. Non-invasive micro-CT scanning revealed that the anterior edge of the swim bladder is largely attached to the os suspensorium, which is an ossicle extending medioventrally from the 4th centrum. Additionally, we observed that hoxc6a mutants, which lack the os suspensorium, exhibited an anterior projection of the swim bladder beyond the 4th vertebra. During the swim bladder development, we found that the counterclockwise rotation of the os suspensorium correlates with posterior regression of the swim bladder, suggesting that the os suspensorium pushes the swim bladder posteriorly into its proper position. Furthermore, our results revealed a close association between the posterior region of the swim bladder and the pleural ribs. In hoxaa cluster mutants with additional ribs, the swim bladder expanded posteriorly, accompanied by an enlarged body cavity. Taken together, our results demonstrate the importance of the surrounding bones in the robust regulation of swim bladder size and position in zebrafish.</p>","PeriodicalId":14971,"journal":{"name":"Journal of Anatomy","volume":" ","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142647705","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The overlooked first intercostal ligament: Does it help to stabilize the Weberian apparatus?","authors":"Jake Leyhr, Tatjana Haitina, Nathan C Bird","doi":"10.1111/joa.14168","DOIUrl":"10.1111/joa.14168","url":null,"abstract":"<p><p>The Weberian apparatus is a novel hearing adaptation that facilitates increased hearing sensitivity in otophysan fishes. The apparatus is a complex system composed of modifications to anterior vertebral elements, the inner ear, and the swim bladder. A critical piece of the system that often receives minor attention are the various ligaments that bridge these three regions. The most famous of the ligaments is the interossicular ligament, which connects the Weberian ossicle chain (scaphium-intercalarium-tripus). Several other ligaments are present, including the suspensor (tripus to parapophysis 4) and the triple ligament (tripus-os suspensorium-tunica externa). Here, by combining diffusible iodine-based contrast enhancement (DICE) and propagation phase-contrast synchrotron radiation micro-computed tomography (PPC-SRμCT) with classic histological methods, we shine new light on the first intercostal ligament (ICL1) and discuss its potential function in relation to the Weberian apparatus. ICL1 is nearly absent from the cypriniform literature, typically only mentioned in a general discussion together with other intercostal ligaments. This study examines the development and structure of ICL1 comparatively with the other definitive Weberian ligaments in the zebrafish (Danio rerio). We provide a comprehensive view of three-dimensional shape, development, and composition to generate hypotheses regarding potential functions of ICL1 within the greater Weberian apparatus. Given new detail presented herein regarding the structure of ICL1, modifications to rib 5 and parapophysis 4 for ICL1 attachment, and the alignment of ICL1 with the os suspensorium, we propose a supportive (anchoring) role of ICL1 to aid in minimizing non-optimal movement of the structures of the fourth vertebra. This addition would focus vibrations anteriorly through the ossicle chain with minimal signal loss in zebrafish and other species with similar Weberian apparatus morphologies. We conclude that ICL1 should be included in future analyses of Weberian apparatus function where ligaments are addressed.</p>","PeriodicalId":14971,"journal":{"name":"Journal of Anatomy","volume":" ","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142647773","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cyclin-dependent kinase 13 is indispensable for normal mouse heart development.","authors":"Qazi Waheed-Ullah, Anna Wilsdon, Aseel Abbad, Sophie Rochette, Frances Bu'Lock, Asma Ali Saed, Marc-Phillip Hitz, J David Brook, Siobhan Loughna","doi":"10.1111/joa.14175","DOIUrl":"10.1111/joa.14175","url":null,"abstract":"<p><p>Congenital heart disease (CHD) has an incidence of approximately 1%. Over the last decade, sequencing studies including large cohorts of individuals with CHD have begun to unravel the genetic mechanisms underpinning CHD. This includes the identification of variants in cyclin-dependent kinase 13 (CDK13), in individuals with syndromic CHD. CDK13 encodes a serine/threonine protein kinase. The cyclin partner of CDK13 is cyclin K; this complex is thought to be important in transcription and RNA processing. Pathogenic variants in CDK13 cause CDK13-related disorder in humans, characterised by intellectual disability and developmental delay, recognisable facial features, feeding difficulties and structural brain defects, with 35% of individuals having CHD. To obtain a greater understanding for the role that this essential protein kinase plays in embryonic heart development, we have analysed a presumed loss of function Cdk13 transgenic mouse model (Cdk13^tm1b). The homozygous mutants were embryonically lethal in most cases by E15.5. X-gal staining showed Cdk13 expression localised to developing facial regions, heart and surrounding areas at E10.5, whereas at E12.5, it was more widely present. In the E15.5 heart, staining was seen throughout. RT-qPCR showed significant reduction in Cdk13 transcript expression in homozygous compared with WT and heterozygous hearts at E10.5 and E12.5. Detailed morphological 3D analysis of embryonic and postnatal hearts was performed using high-resolution episcopic microscopy, which affords a more detailed analysis of structures such as cardiac valve leaflets and endocardial cushions, compared with more traditional histological techniques. We show that both the homozygous and heterozygous Cdk13^tm1b mutants exhibit a range of CHD, including ventricular septal defects, bicuspid aortic valve, double outlet right ventricle and atrioventricular septal defects. 100% (n = 4) of homozygous hearts displayed CHD. Differential expression was seen in Cdk13^tm1b homozygous mutants for two genes known to be necessary for normal heart development. The types of defects, and the presence of CHD in heterozygous mice (17.02%, n = 8/47), are consistent with the CDK13-related disorder phenotype in humans. This study provides important insights into the effects of reduced function of CDK13 in the mouse heart and contributes to our understanding of the mechanism behind this disorder as a cause of CHD.</p>","PeriodicalId":14971,"journal":{"name":"Journal of Anatomy","volume":" ","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142647686","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Axial muscle-fibre orientations in larval zebrafish.","authors":"Noraly M M E van Meer, Johan L van Leeuwen, Henk Schipper, Martin J Lankheet","doi":"10.1111/joa.14161","DOIUrl":"https://doi.org/10.1111/joa.14161","url":null,"abstract":"&lt;p&gt;&lt;p&gt;Most teleost fish propel themselves with lateral body waves powered by their axial muscles. These muscles also power suction feeding through rapid expansion of the mouth cavity. They consist of muscle segments (myomeres), separated by connective tissue sheets (myosepts). In adult teleosts, the fast axial muscle fibres follow pseudo-helical trajectories, which are thought to distribute strain (relative fibre length change) approximately evenly across transverse sections during swimming, thereby optimizing power generation. To achieve strain equalization, a significant angle to the longitudinal axis on the frontal plane (azimuth) is necessary near the medial plane, increasing strain. Additionally, a deviation from longitudinal orientation on the sagittal plane (elevation) is required laterally to decrease strain. Despite several detailed morphological studies, our understanding of muscle-fibre orientations in the entire axial musculature of fish remains incomplete. Furthermore, most research has been done in post-larval stages, leaving a knowledge gap regarding the changing axial muscle architecture during larval development. Larval fish exhibit different body size, body shape and swimming kinematics compared to adults. They experience relatively high viscous forces, requiring higher tail-beat amplitudes to overcome increased drag. Additionally, larval fish swim with higher tail-beat frequencies. Histological studies have shown that in larval fish, muscle fibres in the anal region transition from an almost longitudinal orientation to a pseudo-helical pattern by 3 dpf (days post-fertilization). However, these studies were limited to a few sections of the body and were prone to shrinkage and tissue damage. Here, we introduce a novel methodology for quantifying muscle-fibre orientations along the entire axial muscles. We selected 4 dpf larval zebrafish for our analyses, a stage where larvae are actively swimming but not yet free-feeding. High-resolution confocal 3D scans were obtained from four genetically modified zebrafish expressing green fluorescent protein in fast muscle fibres. Fluorescence variation allowed segmentation of individual muscle fibres, which were then converted to fish-bound coordinates by correcting for the fish's position and orientation in the scan, and normalized to pool results across individuals. We show that at 4 dpf, muscle-fibre trajectories exhibit a helical pattern tapering towards the tail. Average fibre angles decrease from anterior to posterior, with azimuth varying over the dorsoventral axis and elevation varying over the mediolateral axis. Notably, only the anteriormost 20% of the body displayed higher azimuth angles near the medial plane. Angles between neighbouring fibres were substantial, particularly at the rim of the epaxial and hypaxial muscles. The revealed muscle-fibre architecture at this age presumably contributes to the swimming performance of these larvae, but that swimming performance is probably ","PeriodicalId":14971,"journal":{"name":"Journal of Anatomy","volume":" ","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142647619","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Anatomy of spinal CSF loss in the American alligator (Alligator mississippiensis).","authors":"Hadyn DeLeeuw, Michael Cramberg, Matthew Dille, Emily Pick, Mary Thompson, Bruce A Young","doi":"10.1111/joa.14177","DOIUrl":"https://doi.org/10.1111/joa.14177","url":null,"abstract":"<p><p>A variety of anatomical techniques, imaging modalities, dyes and contrast agents, were used to document the mechanisms/routes whereby spinal cerebrospinal fluid (CSF) would move beyond the confines of the spinal dura in the American alligator, Alligator mississippiensis. Three pathways for CSF loss were identified: spinal arachnoid granulations, perineural flow along the spinal nerves, and lymphatic drainage (both along the surface of the dura and at the venous plexus surrounding the spinal ganglion). These same three pathways for spinal CSF loss have been documented in mammals, suggesting that they may be a common feature of (at least) amniotes. Crocodilians, including A. mississippiensis, have the largest epidural venous sinus system of any vertebrate, the present study suggests that, as in mammals, the venous complex of the alligator plays a direct role in regulating the absorption of CSF from the spinal compartment.</p>","PeriodicalId":14971,"journal":{"name":"Journal of Anatomy","volume":" ","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142647575","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sacroiliac joint auricular surface morphology modulates its mechanical environment.","authors":"Petr Henyš, Niels Hammer","doi":"10.1111/joa.14160","DOIUrl":"10.1111/joa.14160","url":null,"abstract":"<p><p>The sacroiliac joint (SIJ) exhibits significant variation in auricular surface morphology. This variation influences the mechanics of the SIJ, a central node for transmitting mechanical energy from upper body to lower limbs and vice versa. The impact of the auricular surface morphology on stress and deformation in the SIJ remains poorly understood to date. Computed tomography scans obtained from 281 individuals were included to extract the geometry of the pelvic ring. Then, the auricular surface area, SIJ cartilage thickness, and total SIJ cartilage volume were identified. Based on these reconstructions, 281 finite element models were created to simulate SIJ mechanical loading. It was found that SIJ cartilage thickness only weakly depended on age or laterality, while being strongly sex sensitive. Auricular surface area and SIJ cartilage volume depended weakly and non-linearly on age, peaking around menopause in females, but without significant laterality effect. Larger SIJs, characterized by greater auricular area and cartilage volume, exhibited reduced stress and deformation under loading. These findings highlight the significant role of SIJ morphology in its biomechanical response, suggesting a potential link between morphological variations and the risk of SIJ dysfunction. Understanding this relationship could improve diagnosis and targeted treatment strategies for SIJ-related conditions.</p>","PeriodicalId":14971,"journal":{"name":"Journal of Anatomy","volume":" ","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142647770","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Issue Cover (December 2024)","authors":"","doi":"10.1111/joa.14084","DOIUrl":"https://doi.org/10.1111/joa.14084","url":null,"abstract":"<p>\u0000 <b>Front cover:</b>\u0000 </p><p>Cover image: see M. Didziokas et al., ‘BounTI (Boundary-preserving Threshold Iteration): a user-friendly tool for automatic hard tissue segmentation’, this issue.</p><p>\u0000 \u0000 <figure>\u0000 <div><picture>\u0000 <source></source></picture><p></p>\u0000 </div>\u0000 </figure>\u0000 </p>","PeriodicalId":14971,"journal":{"name":"Journal of Anatomy","volume":"245 6","pages":"i"},"PeriodicalIF":1.8,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/joa.14084","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142665866","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Editorial: Advances in craniosynostosis—Basic science to clinical practice","authors":"Mehran Moazen,&nbsp;Stephen R. F. Twigg","doi":"10.1111/joa.14126","DOIUrl":"10.1111/joa.14126","url":null,"abstract":"&lt;p&gt;Craniosynostosis is a serious congenital condition caused by early fusion of the cranial sutures, the joints between the flat bones of the skull. Current treatment involves a multidisciplinary team of plastic and maxillofacial surgeons, neurosurgeons, speech and language therapists, psychologists, orthoptists, dentists, clinical geneticists and other specialists. Scientists from different disciplines are working together to advance our fundamental understanding of the causes and treatment of this condition using a wide range of approaches. This is clearly a joint transdisciplinary effort involving multiple stakeholders with the children and their families at the heart.&lt;/p&gt;&lt;p&gt;Each of the aforementioned groups and disciplines that are engaged in treatment/research on craniosynostosis have their own societies and conferences. Some examples are the International Society of Craniofacial Surgery, the Gordon Research Conference on Craniofacial Morphogenesis and Tissue Regeneration, the European Society for Pediatric Neurosurgery and many others that are increasingly becoming more interdisciplinary.&lt;/p&gt;&lt;p&gt;The idea behind the “Advances in Craniosynostosis – basic science to clinical practice” (AdCr) meeting originated in 2011 when Moazen promised the Royal Academy of Engineering Research Fellowship Scheme “… to organize a workshop on &lt;i&gt;the use of computational skull models in clinical applications.”&lt;/i&gt; As the fellowship progressed it became increasingly clear that there was a need to bring together all the key stakeholders involved in treatment and research on craniosynostosis, including the patients and their families.&lt;/p&gt;&lt;p&gt;The RAEng Fellowship engendered wider interaction with multiple colleagues working on various aspects of craniosynostosis. Prof Michael Fagan, Prof Andrew Willkie, Prof Susan Herring, Mr David Johnson and Prof Michael Cunningham had supported the initial application and through the years that followed this network expanded. This included interaction with the Headlines Craniofacial Support Charity that is run by families affected by craniosynostosis. Moazen's move to UCL enabled wider interaction with many other colleagues including Dr Erwin Pauws and Prof Karen Liu in London and Dr Steve Twigg in Oxford, forming a team to organise the meeting as was envisaged back in 2011.&lt;/p&gt;&lt;p&gt;On 27 July 2018, we organised the first AdCr at UCL. Following the success of that conference, we felt there was sufficient interest and enthusiasm for a regular meeting and the second and third AdCr followed on 27 August 2021, and 25 August 2023, respectively. We are very keen to continue these meetings and to expand them to ensure that we have a united and well-connected community working on craniosynostosis, more so considering that this is still a rather under-funded condition.&lt;/p&gt;&lt;p&gt;The third AdCr meeting celebrated the lifetime impact and achievements of Prof Gillian Morriss-Kay in craniofacial research, as well as her significant contribution to t","PeriodicalId":14971,"journal":{"name":"Journal of Anatomy","volume":"245 6","pages":"813-814"},"PeriodicalIF":1.8,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11547217/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142603309","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Microstructure and development of the dermal ossicles of Antarctopelta oliveroi (Dinosauria, Ankylosauria): A complex morphogenetic system deciphered through three-dimensional X-ray microtomography.","authors":"Sophie Sanchez, Armand de Ricqlès, Jasper Ponstein, Paul Tafforeau, Louise Zylberberg","doi":"10.1111/joa.14159","DOIUrl":"https://doi.org/10.1111/joa.14159","url":null,"abstract":"<p><p>Ankylosaurs were a group of heavily armored non-avian dinosaurs (Dinosauria, Ankylosauria), represented by a relatively abundant fossil record from the Cretaceous of North and South America. Their dermal skeleton was characterized by large osteoderms whose development and functional role have been largely investigated. However, interstitial small ossicles, forming between these osteoderms, have been far more overlooked and it remains unknown whether they were formed through the ossification of a preexisting fibrous matrix of connective tissue (i.e., metaplasia) or by a cell-induced differentiation of new fiber bundles followed by mineralization (i.e., neoplasia sensu (Zeitschrift für Wissenschaftliche Zoologie, 1858, 9, 147)). Here, we propose a hypothesis on the developmental origin of these small ossicles in the ankylosaurian Antarctopelta oliveroi using light microcopy, scanning electron microscopy and three-dimensional virtual histology through propagation phase-contrast synchrotron radiation micro-computed tomography (PPC-SRμCT). Ossicles are located in the dermis. They are composed of two layers: (1) a thin external layer, and (2) a thick basal plate, composed of collagen fiber bundles, which forms the main part of the ossicle. The external layer is made of a smooth, vitreous mineralized tissue that does not look like bone. The basal plate, however, is of osseous origin. In this basal plate, the collagen fiber bundles are organized in two orthogonal systems: one horizontal-observable in cross-sections-and one vertical-observable in the primary plane of sections sensu (Journal of Vertebrate Paleontology, 2004, 24, 874). The horizontal system is itself composed of successive layers of collagen fiber bundles arranged into an orthogonal plywood-like structure. The bundles of the vertical system radiate from the center of the ossicle at the level of the transition between the external layer and the basal plate and run towards the periphery of the basal plate. Their thickness increases from the center of the ossicle towards its periphery. Numerous bundles of the vertical system form thin threads that interweave and penetrate within the thick bundles of the horizontal system. Our new data suggest that the ossicles were at least partially formed by metaplasia, that is, through the ossification of a preexisting fibrous matrix of connective tissue. This process was probably supplemented by a cell-induced differentiation of new fiber bundles laid down prior to their incorporation into the fibrous system and its mineralization. This process looks more akin to neoplasia sensu (Zeitschrift für Wissenschaftliche Zoologie, 1858, 9, 147) than to metaplasia. Consequently, metaplastic and neoplastic processes may coexist in these ossicles with a possible differential expression during ontogeny.</p>","PeriodicalId":14971,"journal":{"name":"Journal of Anatomy","volume":" ","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142576225","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}