Josemberg da Silva Baptista

Purpose: Accessory muscles between the levator scapulae and serratus posterior superior are rarely reported and may be interpreted as variants of either adjacent muscle. This study describes bilateral accessory muscles in the posterior cervical and upper thoracic region and discusses their anatomical classification and clinical relevance. Methods: A routine anatomical dissection was performed in a formalin-fixed adult male cadaver. The posterior cervical and upper thoracic regions were dissected to define the topography, attachments, morphology, distal interface, and innervation of the accessory muscles. Morphometric measurements were obtained bilaterally using a caliper. Results: Bilateral elongated muscular structures were identified between the levator scapulae and serratus posterior superior muscles. Each muscle had an individual proximal attachment at the transverse process of the second cervical vertebra, followed an inferomedial course approximately parallel to the splenius capitis, and remained distinct from the main belly of the levator scapulae. Distally, each muscle was separated from the serratus posterior superior by a bursal interface, without direct muscular or aponeurotic continuity or independent scapular insertion. Both muscles were bicipital and fusiform and were innervated by posterior rami that also supplied the splenius capitis. Conclusion: These findings support the interpretation of the structures as paired individualized accessory muscles rather than accessory slips of adjacent muscles, expanding the known spectrum of posterior cervical and upper thoracic anatomical variations.

Objective: The extensor digitorum brevis manus (EDBM) is an infrequent anatomical variation on the dorsum of the hand, with an estimated prevalence of 2%. Morphologically, type III is the rarest variant. The purpose of this study is to provide a detailed morphological description of a rare specimen of the EDBM, classified as type III, and to analyze its biomechanical implications and clinical relevance in the differential diagnosis. Materials and methods: A meticulous anatomical dissection was performed on the dorsal surface of the left hand of a male cadaver. Morphometric analysis was conducted using a digital caliper to record the precise dimensions of the muscle belly and its associated tendon. Results: An accessory muscular structure was identified deep to the tendons of the extensor digitorum muscle, located medially to the extensor indicis muscle. The muscle originated from the dorsal radiocarpal ligament at the distal portion of the radius and inserted into the medial margin of the extensor expansion of the middle finger. This configuration corresponds to the type III variant by Ogura et al., which represents the rarest variant described in the literature. Conclusions: The EDBM is a significant anatomical variation often misdiagnosed as a ganglion or synovial cyst due to lack of awareness among clinicians. Understanding its rarest subtypes, such as type III, is essential for improving clinical practices and surgical management thereby enhancing the quality of life for symptomatic patients.

Background: In this study, we provide a comprehensive description of the morphometrics of the distal tibiae and propose that the intact posterior malleolus (PM) exhibits clinically relevant morphologic variation. These differences may have implications for fracture classification, fixation strategy, and implant design. Methods: Fifty-two isolated dry tibias were analyzed to determine the PM morphometric parameters. Five key morphometric points were identified, and the PM was defined as the posterior bony projection of the distal tibial epiphysis. The malleolar groove established the PM’s medial limitation, the posterior portion of the fibular notch defined the lateral limit, and the anterior boundary was a line connecting these landmarks across the inferior articular surface. PM shapes were categorized based on consistent morphologic patterns. Cross-sections of the distal tibia were performed to assess trabecular bone morphology and density. Results: We found the PM presenting 3 distinct morphologic types: rounded, triangular, and trapezoid. Triangular and trapezoid types exhibited larger dimensions and robust bone tissue, whereas tibias with a rounded PM displayed smaller dimensions and delicate bone architecture. Conclusion: These novel findings reveal PM morphologic diversity, which may enhance our understanding of PM fracture patterns and optimize the development of surgical implants.

When developing, the mandible presents great plasticity and contains condensed mesenchymal cells that develops into Meckel's cartilage, of which the anterior part forms the mandibular symphysis. Mandible human development studies focus on investigating whether the beginning of mandibular fusion in fetal period is related to symphysis ossification and the tensions imposed on it, considering that tongue movements, mouth opening, and closing can be seen in fetuses. This research analyses tissue modifications during human mandibular symphysis growth using light and scanning electron microscopy to relate them to its functional structure. The study sample consisted of 12 human fetuses distributed into two groups: Group I (GI) of 10–14 weeks old and Group II (GII) of 20–24 weeks old. Fragments of mandibular symphysis were removed en bloc together with the surrounding tissues to preserve the relation with adjacent structures. Decalcified specimens were prepared in semi‐serial coronal sections 5‐μm‐thick and stained with hematoxylin and eosin, Masson՚s trichrome, Verhoeff, and Sirius red for histological analysis with light microscopy. Collagen fibers Type I or III and elastic fibers were quantified by volume fraction (Vv). Coronal sections of the GI and GII symphyseal region were submitted to scanning electron microscopy. Comparison between groups used independent t‐test. Our study presents the different endochondral ossification stages in the anterior part of Meckel's cartilage in GI. Both groups showed abundantly vascularized mesenchymal tissue with intense cellular activity forming the mandibular symphysis, such as a source of new osteoblasts adjacent to the newly deposited bone matrix. Scanning electron microscopy analysis revealed an invasion of the bony trabecula in the transverse direction from the hemimandible, rectilinear in GI and sinuous in GII due to interdigitating bone process, promoting its ossification. In collagen Vv analysis was verified a prevalence of type I in GII and type III in GI, indicating a proportional relation between maturation and tissue arrangement. Functionally, the collagen and elastic fibers in the mandibular symphysis were arranged in a pantographic network, and the fibrillar interconnectivity clearly contributes to resilience capacity and efficiency of the force transfer. This study inferred the functional significance of the knowledge about the tissue composition of mandibular symphysis, and the importance of this tissue for surrounding structures. The mesenchymal tissue of mandibular symphysis participates in bone growth process, revealing an adaptation mechanism of mandibular symphysis in the fetal period investigated.

Maria Cecília Baratela, William Paganini Mayer, Josemberg da Silva Baptista. Anat Cell Biol -0001;0:. https://doi.org/10.5115/acb.24.052

The infraorbital foramen (IOF) serves as an important anatomical reference for infraorbital nerve block during different procedures. Its clinical and surgical relevance, associated with conflicting results in its anatomy description justifies the present study. Thus, this work aims to describe the IOF, qualitatively and quantitatively, and propose an accurate measurement to define its location. One hundred and seventy-four IOFs of dry skulls were analyzed and divided in dentate (DE) and edentulous (ED) groups. Distances were measured between the IOF and the margin of the alveolar arch of the maxilla (MAAM), the inferior orbital margin (IOM), the intermaxillary suture (IMS), the vertical plane of IOF. A new methodology was proposed to optimize the identification of IOF based on the IMS distance. Oval-shaped IOFs (n=81/174) with inferomedial orientation (n=104/174) and with a crest-shaped upper margin (n=163/174) constituted the norm for this sample. Distance between IOF and MAAM was 29.97 ± 4.09 mm, to IOM 7.27 ± 1.8 mm, and to IMS 35.09 ± 3.77 mm. ED individuals had IOF closer to MAAM (p=0.0124). The highest point of this methodology was the lack of statistical differences in the IMS distance in ED and DE specimens, making this method applicable for both. Therefore, to minimize iatrogenic injuries, clinicians and surgeons must consider the total or partial presence of teeth, the methodology established to find the IOF, its inferomedial orientation, and the prevalent crest on its superior margin.

Purpose The increase in ankle sprains in children is a reflection of the greater inclusion of this population in sports. This places the calcaneofibular (CFL) and the anterior talofibular (ATFL) ligaments in focus for study. In adults, the presence of arcuate fibers extending between these two ligaments suggests the existence of a new anatomical and functional complex called the lateral fibulotalocalcaneal ligament of the ankle (LFTCL), which can be associated with the persistence of instability of the talocrural joint in ankle sprains. This study aimed to verify the presence of arciform fibers between the CFL and ATFL in human fetuses and to study the topography of the lateral ankle region. Methods Forty matched fetal ankles aged between 28 and 38 weeks, fixed in 4% formalin, were macroscopically, chemically and mesoscopically dissected and analyzed in stereoscope. Results The ATFL was characterized as a capsular ligament consisting of two fascicles (proximal and distal). The CFL was characterized as an extracapsular ligament. The LFTCL complex was verified in all specimens, characterized by the arcuate fibers between the ATFL and the CFL. Conclusion Such results suggest that this functional unit is congenital and that it should be taken into consideration in the treatment of persistent ankle instabilities in the pediatric population.

The present study aims to dissect and identify the Barkow ligament (LB) in fetal specimens and describe its anatomical characteristics to contribute to its knowledge in the pediatric population and the clinical and surgical application of conditions associated with the Craniovertebral Junction (CVJ). ). Methods: This work evaluated 19 human fetuses aged 28-38 weeks. Of these, six specimens constituted the final sample and were studied through detailed dissections using coronal sections in an anterior approach up to the region described by the LB. Results: In all specimens, a thin fibrous band was found, horizontal and anterior to the axis tooth, with bilateral fixation on the occipital condyles, corroborating the results found for describing LB in adults. Conclusion: The LB is a congenital ligament that resists the extension of the atlantooccipital joint and may play a role in the stability of the CVJ. Level of Evidence III; Diagnostic Study.

Orthosis immobilisations are routinely used in orthopaedic procedures. This intervention is applicable in bone fractures, ligament injuries, and tendonitis, among other disorders of the musculoskeletal system. We aimed to evaluate the effects of ankle joint functional immobilisation on muscle fibre morphology, connective tissue, muscle spindle and fibre typification triggered by a novel metallic orthosis. We developed a rodent-proof experimental orthosis able to hold the tibiotalar joint in a functional position for short and long terms. The tibialis anterior muscles of free and immobilised legs were collected and stained by histology and histochemistry techniques to investigate general muscle morphology, connective tissue and muscle fibre typification. Morphometric analysis of muscle cross-section area, fibre type cross-section area, fibre type density, percentage of intramuscular connective tissue, and thickness of the muscle spindle capsule were obtained to gain insights into the experimental protocol. We found that short- and long-term immobilisation decreased the cross-section area of the muscles and induced centralisation of myonuclei. The connective tissue of immobilised muscle increased after 2 and 4 weeks mainly by deposition of type III and type I collagen fibres in the perimysium and endomysium, respectively, in addition to muscle spindle capsule thickening. Type IIB muscle fibre was severely affected in our study; the profile assumed odd shapes, and our data suggest interconversion of these fibre types within long-term immobilisation. In conclusion, our protocol has produced structural and histochemical changes in muscle biology. This method might be applied to various rodent models that enable genetic manipulation for the investigation of muscle degeneration/regeneration processes.

Em regiões tropicais com forte sazonalidade, a atividade reprodutiva de muitas espécies ocorre nos períodos mais adequados do ano. Portanto, vários ajustes fisiológicos e comportamentais são necessários durante seu ciclo reprodutivo. Este estudo tem como objetivo avaliar possíveis alterações nos parâmetros histológicos e morfométricos dos ovários, bem como nos níveis plasmáticos de estrogênio e progesterona de fêmeas de Leptodactylus macrosternum e sua relação com a temperatura e precipitação. Os espécimes foram coletados na área do Horto Florestal Olho d'Água da Bica - HFOB (06 ° 49´20''S / 36 ° 15´85''W) no município de Cuité, semiárido brasileiro, a cada 15 dias, apenas entre os meses de maio a agosto e de novembro a dezembro. A quantificação da densidade populacional dos tipos de ovócitos e dosagens de progesterona e níveis de estrogênio foram utilizados para determinar a atividade reprodutiva das espécies. As densidades populacionais de oogônios e oócitos II não variaram significativamente durante os meses em que os animais foram amostrados. As densidades populacionais do oócito I foram significativamente maiores durante os meses de junho (p = 0,04) e agosto (p = 0,03). Os maiores valores para a densidade populacional do oócito III e IV foram encontrados nos meses de maio (p = 0,04 ) e junho (p = 0,04). As quantidades de concentrações de estrogênio (pg / ml) e progesterona (pg / ml) não se alteraram significativamente ao longo dos períodos de amostragem. A densidade populacional dos tipos de ovócitos III e IV mostrou dependência da variação da precipitação.