Rotura do peitoral maior: relato de caso de uma rotura incomum / Pectoralis major rupture: case report of an unusual rupture / Rotura del pectoral mayor: informe de un caso de rotura inusual

Apesar de não muito frequente, nos últimos 20 anos, houve um aumento significativo dos relatos sobre rotura do peitoral maior, normalmente associadas à prática de atividade física em que ocorre contração intensa e/ou uso de cargas pesadas exercendo resistência sobre o músculo. Neste relato de caso temos um paciente de 51 anos referindo dor no tórax à direita e no braço direito há 3 dias após tentar consertar o guidão da moto. Apresentava assimetria dos peitorais, perda de força do membro superior direito, dificuldade de movimentação e hematoma. A ressonância magnética demonstrou rotura completa da junção miotendínea do peitoral maior, com tendinopatia com fissuras insercionais e intrasubstanciais infraespinhal e tendinopatia com rotura parcial do tendão subescapular. Foi indicado por médico ortopedista o acompanhamento com o uso de medicação analgésica.

Although not very common, in the last 20 years, there has been a significant increase in reports of rupture of the pectoralis major, normally associated with the practice of physical activity in which intense contraction occurs and/or the use of heavy loads exerting resistance on the muscle. In this case report we have a 51-year-old patient reporting pain in his right chest and right arm for 3 days after trying to fix his motorcycle's handlebars. He had asymmetry of the pectorals, loss of strength in the right upper limb, difficulty moving and hematoma. Magnetic resonance imaging demonstrated complete rupture of the myotendinous junction of the pectoralis major, with tendinopathy with insertional and intrasubstantial infraspinatus fissures and tendinopathy with partial rupture of the subscapularis tendon. An orthopedic doctor recommended follow-up with the use of analgesic medication.

Aunque no es muy común, en los últimos 20 años se ha observado un aumento significativo en los reportes de rotura del pectoral mayor, normalmente asociado a la práctica de actividad física en la que se produce una contracción intensa y/o al uso de cargas pesadas ejerciendo resistencia sobre el mismo. el músculo. En este caso clínico tenemos un paciente de 51 años que refiere dolor en el pecho derecho y en el brazo derecho durante 3 días después de intentar arreglar el manillar de su motocicleta. Presentó asimetría de pectorales, pérdida de fuerza en miembro superior derecho, dificultad de movimiento y hematoma. La resonancia magnética demostró rotura completa de la unión miotendinosa del pectoral mayor, con tendinopatía con fisuras de inserción e intrasustancial del infraespinoso y tendinopatía con rotura parcial del tendón subescapular. Un médico ortopédico recomendó seguimiento con el uso de medicación analgésica.

Exploring the relationship between trunk muscles and lower limb injuries in Australian badminton players.

Due to its dynamic nature, lower limb injuries are common in badminton. Overuse injuries of the knee, including tendon related conditions, are the most common. During jumping and landing, force transference and dissipation through the trunk is required, with the trunk muscles playing a vital role. However, the relationship between knee pain and the ability to voluntarily contract the trunk muscles has not yet been explored in badminton players. A cross-sectional study of Australian badminton players was therefore conducted. Players performed a single leg decline squat to identify those with knee pain. Ultrasound imaging was used to image and measure the size of the multifidus and quadratus lumborum, and the ability to contract the abdominal and multifidus muscles. Voluntary contraction of the trunk muscles was conducted with the subjects lying down. Independent samples T-Tests were performed to test for between group differences. Badminton players with knee pain had larger quadratus lumborum muscles and demonstrated a greater change in muscle thickness from the rested to contracted state. While we cannot comment on causation or direction, over co-contraction of trunk muscles has been shown in other studies to be associated with increased ground reaction forces on landing. Motor control training has been successfully used in other conditions to modify trunk muscle recruitment patterns and may therefore potentially represent a useful approach for badminton players.

The misuse of respiratory resistive loading during aerobic exercises: revisiting mechanisms of "standalone" inspiratory muscle training.

Systematic reviews and meta-analyses support the benefits of inspiratory muscle training (IMT) for sports and clinical populations. A typical application of "standalone" IMT intervention consists of breathing against an inspiratory load (IRL), twice daily, for five to seven days per week, for four to twelve weeks. However, the application of IRL during aerobic exercise is often seen in a training routine of sports and rehabilitation centres with noevidence­based guide. In this Current Opinion, we will revisit putative mechanisms underlying the established benefits of "standalone" IMT to support our contention that IMT need not and should not be used during aerobic exercise.

The Association Between Respiratory Functions, Pain Tolerance and Body Awareness in Obstructive Lung Diseases.

PURPOSE: There are only a limited number of studies in the literature evaluating body awareness, pain perception, and the relationship between clinical parameters and respiratory functions in patients with obstructive lung disease (OLD) and compared with healthy individuals. Therefore, this study aimed to evaluate respiratory functions, pain tolerance, and body awareness in patients with OLD and compare these findings with those of healthy individuals. METHODS: The study included 33 patients and 30 healthy individuals. The respiratory function (spirometer), respiratory muscle strength (mouth pressure device), endurance (threshold loading device), pain level and tolerance (short-form McGill Pain Questionnaire and algometer), posture, and body awareness (Body Awareness Questionnaire-BAQ) were evaluated. RESULTS: The pain threshold and tolerance of the biceps, triceps, trapezius, and quadriceps muscles were significantly lower and BAQ scores were higher in patients with OLD compared with healthy individuals (p < .05). There was a significant relationship between FEV1 (%) and pain tolerance of the triceps (r = 0.371, p = .047) and gastrocnemius muscles (r = 0.419, p = .024); FVC (%) and pain threshold of the gastrocnemius (r = 0.413, p = .023), triceps muscles (r = 0.394, p = .034), and pain tolerance of the gastrocnemius muscle (r = 0.549, p = .002). CONCLUSIONS: Patients with OLD have a marked increase in pain perception and body awareness levels and a decrease in pain threshold and tolerance compared with healthy controls. Future studies should assess the effectiveness of pain management interventions as a part of pulmonary rehabilitation for patients with chronic respiratory diseases. CLINICAL IMPLICATIONS: Pain management is important for planning pulmonary rehabilitation programmes.

Local and non-local effects (on the posterior chain) of four weeks of foot exercises: a randomized controlled trial.

This study investigated the local, remote, and contralateral effects of a four-week intrinsic foot muscle exercise intervention in recreationally active participants on foot parameters, flexibility, and performance of the posterior chain (PC). Twenty-eight healthy participants (12f, 16m) were randomly assigned to a control group or performed 2 × 6 min of foot exercises twice daily unilaterally at least five days/week for four weeks. At baseline (M1), after the intervention (M2), and after a four-week wash-out period (M3), we assessed bilateral Foot Posture Index-6, medial longitudinal arch mobility, single-leg stance balance, range of motion (ROM) (first metatarsophalangeal joint and ankle), and flexibility and performance of the PC. The FPI-6 score changes over time differed significantly between groups for both legs, improving by 26% in the trained- (p < .001) and 11% in the untrained leg (p = .02) in the intervention group from M1 to M2. Improvements were maintained at M3 for the trained leg (p = .02). Ankle range of motion and balance of the trained leg improved from M1 to M2, yet only became significant at M3 (ROM: p = .02; balance: p = .007). The other parameters did not change significantly. A four-week foot exercise intervention might have local but no remote effects in healthy young adults.German Clinical Trial Register (DRKS00027923) (24/08/2022).

Emerging innovations in electrically powered artificial muscle fibers.

This review systematically explores the inherent structural advantages of fiber over conventional film or bulk forms for artificial muscles, emphasizing their enhanced mechanical properties and actuation, scalability, and design flexibility. Distinctive merits of electrically powered artificial muscle fiber actuation mechanisms, including electrothermal, electrochemical and dielectric actuation, are highlighted, particularly for their operational efficiency, precise control capabilities, miniaturizability and seamless integration with electronic components. A comprehensive overview of significant research driving performance enhancements in artificial muscle fibers through materials and structural innovations is provided, alongside a discussion of the diverse design methodologies that have emerged in this field. A detailed comparative assessment evaluates the performance metrics, advantages and manufacturing complexities of each actuation mechanism, underscoring their suitability for various applications. Concluding with a strategic outlook, the review identifies key challenges and proposes targeted research directions to advance and refine artificial muscle fiber technologies.

Exercise, autoimmune diseases and T-regulatory cells.

Diverse forms of physical activities contribute to improvement of autoimmune diseases and may prevent disease burst. T regulatory cells (Tregs) maintain tolerance in autoimmune condition. Physical activity is one of the key factors causing enhancement of Tregs number and functions, keeping homeostatic state by its secrotome. Muscles secrete myokines like IL-6, PGC1α (PPARγ coactivator-1 α), myostatin, transforming growth factor ß (TGF-ß) superfamily), IL-15, brain derived neurotrophic factor (BDNF) and others. The current concept points to the role of exercise in induction of highly functional and stable muscle Treg phenotype. The residing-Tregs require IL6Rα signaling to control muscle function and regeneration. Skeletal muscle Tregs IL-6Rα is a key target for muscle-Tregs cross-talk. Thus, interplay between the Tregs-skeletal muscle, following exercise, contribute to the balance of immune tolerance and autoimmunity. The cargo delivery, in the local environment and periphery, is performed by extracellular vesicles (EVs) secreted by muscle and Tregs, which deliver proteins, lipids and miRNA during persistent exercise protocols. It has been suggested that this ensemble induce protection against autoimmune diseases.

Dynamic and static nasolabial muscle anatomy of unilateral cleft lip adult patients based on magnetic resonance imaging data.

OBJECTIVES: This study aims to obtain a three-dimensional reconstruction model based on magnetic resonance imaging (MRI) data of patients with different degrees of unilateral cleft lip and analyze the anatomy and changes in multiple groups of nasolabial muscles under dynamic and static conditions. METHODS: One normal person and four adult patients with unilateral cleft lip were included, and MRI was performed under static (upper and lower lips closed naturally) and dynamic (pout and grin) conditions. 3D Slicer software was used to reconstruct the model and draw the anatomic morphology of nasolabial muscles. The distance between the junction (where the muscle merges into the orbicularis oris) of the levator muscle, zygomaticminor muscle, and zygomatic major muscle to the median sagittal plane, the starting point to the junction point, the dynamic and static junction points, and the angle between the connection of dynamic and static junctions and the horizontal plane were measured under three kinds of movements, and the ratio was calculated. RESULTS: In all patients, under dynamic and static conditions, the distance from the muscle junction to the median sagittal plane, their ratios of the cleft side to the non-cleft side were all greater than 1. While the ratio of the distance from the starting point of the muscle to the junction point is less than 1. At static conditions, the two ratios of the same muscle increased gradiently with the severity of the cleft, and the ratio of the zygomatic minor muscle was prominent in the same patient. The ratio of the cleft side to the non-cleft side was greater than 1, and the value for comparison was the angle of the line from the static to the dynamic junction and the horizontal plane. CONCLUSIONS: The symmetry of the insertion site of the orbicularis oris and the linear distance of both sides of the muscle are related to muscle and cleft types. The angle of muscle contraction on the cleft side is greater than that on the non-cleft side.

Coactivation of the Laryngeal Muscles in Pigs Without External Neural Control Indicates Existence of an Intrinsic Neuronal Network.

Electrophysiological studies of the larynx expose the mechanisms by which voice production is controlled. Previous studies have revealed certain phenomena during laryngeal oscillations that suggest a complex control mechanism. Starting from the principle of agonist-antagonist muscular pairing, the aim of this study was to gain a deeper insight into the function of the cricothyroid (CT) and thyroarytenoid (TA) muscles, both central to voice production. Electromyographic recordings were used to determine the response of the two muscles to different stimulation situations in an ex vivo animal model of the denervated larynx of pigs (n=26). Using a set of different experiments, it was shown that when one muscle (CT or TA muscle) was electrically stimulated, a response was observed in the other muscle, which in the otherwise-denervated larynx, was caused only by the applied stimulation and exhibited the characteristics of compound action potentials. This response was reproducible in all larynxes examined and was present bidirectionally. No response was registered in the absence of stimulation. The results show the existence of coactivation of the CT and TA muscles in the absence of external innervation hinting at the presence of a localized neuronal network of the larynx that has not been described previously. Further morphological investigation is needed to determine the presence of this internal laryngeal neuronal network.

Expiratory Muscle Strength Training Reduces Oxidative Stress and Systemic Inflammation in Men with Obstructive Sleep Apnea Syndrome: A Double-Blinded, Randomized Parallel Trial.

STUDY OBJECTIVES: This study aimed to evaluate and compare the effects of high and low-intensity expiratory muscle strength training (EMST) on disease severity, systemic inflammation, oxidative stress, respiratory muscle strength, exercise capacity, symptoms, daytime sleepiness, fatigue severity, and sleep quality in male patients with obstructive sleep apnea syndrome (OSAS). METHODS: Thirty-one male patients diagnosed with moderate OSAS were included in this double-blind, randomized, parallel study. Patients were randomized into two groups: High-EMST and Low-EMST groups. EMST was used at home 7 days/week, once a day, for 25 breaths, 12 weeks. Respiratory muscle strength was measured using a mouth pressure device. Disease severity (Apne Hipopne Index-AHI) and, respiratory sleep events by polysomnography, total oxidant level(TOS), total antioxidant level(TAS), oxidative stress index (OSI), C-reactive protein (CRP), tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and interleukin-10 (IL-10) levels by blood serum were evaluated. RESULTS: The percentage of AHI change in the High-EMST group(50.8%) was significantly higher than in the Low-EMST group(6.3%) (p=0.002, d=1.31). In general, as MEP increased by one unit, AHI decreased by 0.149 points (b=-0.149; CR=-3.065; p=0.002), and as AHI increased by one unit, ODI increased by 0.746 points (b=0.746; CR=10.604; p<0.001). TOS, OSI, TNF-α and IL-6 levels decreased at similar rates in both groups. CONCLUSION: EMST significantly reduces systemic inflammation and oxidative stress while improving expiratory muscle strength in male patients with moderate OSAS. High-EMST is more effective in enhancing the severity of disease than Low-EMST. EMST is a practical, effective, and promising treatment for pulmonary rehabilitation in patients with moderate OSAS.

Assessing muscle invasion in bladder cancer via virtual biopsy: a study on quantitative parameters and classical radiomics features from dual-energy CT imaging.

OBJECTIVE: To evaluate the prediction value of Dual-energy CT (DECT)-based quantitative parameters and radiomics model in preoperatively predicting muscle invasion in bladder cancer (BCa). MATERIALS AND METHODS: A retrospective study was performed on 126 patients with BCa who underwent DECT urography (DECTU) in our hospital. Patients were randomly divided into training and test cohorts with a ratio of 7:3. Quantitative parameters derived from DECTU were identified through univariate and multivariate logistic regression analysis to construct a DECT model. Radiomics features were extracted from the 40, 70, 100 keV and iodine-based material-decomposition (IMD) images in the venous phase to construct radiomics models from individual and combined images using a support vector machine classifier, and the optimal performing model was chosen as the final radiomics model. Subsequently, a fusion model combining the DECT parameters and the radiomics model was established. The diagnostic performances of all three models were evaluated through receiver operating characteristic (ROC) curves and the clinical usefulness was estimated using decision curve analysis (DCA). RESULTS: The normalized iodine concentration (NIC) in DECT was an independent factor in diagnosing muscle invasion of BCa. The optimal multi-image radiomics model had predictive performance with an area-under-the-curve (AUC) of 0.867 in the test cohort, better than the AUC = 0.704 with NIC. The fusion model showed an increased level of performance, although the difference in AUC (0.893) was not statistically significant. Additionally, it demonstrated superior performance in DCA. For lesions smaller than 3 cm, the fusion model showed a high predictive capability, achieving an AUC value of 0.911. There was a slight improvement in model performance, although the difference was not statistically significant. This improvement was observed when comparing the AUC values of the DECT and radiomics models, which were 0.726 and 0.884, respectively. CONCLUSION: The proposed fusion model combing NIC and the optimal multi-image radiomics model in DECT showed good diagnostic capability in predicting muscle invasiveness of BCa.

Spine muscle auto segmentation techniques in MRI imaging: a systematic review.

BACKGROUND: The accurate segmentation of spine muscles plays a crucial role in analyzing musculoskeletal disorders and designing effective rehabilitation strategies. Various imaging techniques such as MRI have been utilized to acquire muscle images, but the segmentation process remains complex and challenging due to the inherent complexity and variability of muscle structures. In this systematic review, we investigate and evaluate methods for automatic segmentation of spinal muscles. METHODS: Data for this study were obtained from PubMed/MEDLINE databases, employing a search methodology that includes the terms 'Segmentation spine muscle' within the title, abstract, and keywords to ensure a comprehensive and systematic compilation of relevant studies. Systematic reviews were not included in the study. RESULTS: Out of 369 related studies, we focused on 12 specific studies. All studies focused on segmentation of spine muscle use MRI, in this systematic review subjects such as healthy volunteers, back pain patients, ASD patient were included. MRI imaging was performed on devices from several manufacturers, including Siemens, GE. The study included automatic segmentation using AI, segmentation using PDFF, and segmentation using ROI. CONCLUSION: Despite advancements in spine muscle segmentation techniques, challenges still exist. The accuracy and precision of segmentation algorithms need to be improved to accurately delineate the different muscle structures in the spine. Robustness to variations in image quality, artifacts, and patient-specific characteristics is crucial for reliable segmentation results. Additionally, the availability of annotated datasets for training and validation purposes is essential for the development and evaluation of new segmentation algorithms. Future research should focus on addressing these challenges and developing more robust and accurate spine muscle segmentation techniques to enhance clinical assessment and treatment planning for musculoskeletal disorders.

The relationship between the ratio of the supraspinatus muscle thickness measured by ultrasound imaging and glenohumeral subluxation in stroke patients: a cross-sectional study.

Introduction: Glenohumeral subluxation (GHS) is a common complication in stroke patients with hemiplegia, occurring in approximately 17-81% of cases. This study aims to evaluate the relationship between shoulder muscle thickness and the degree of subluxation using ultrasound imaging. Methods: A cross-sectional study of 61 stroke patients with hemiplegia was conducted, measuring supraspinatus muscle thickness, deltoid muscle thickness, and acromion-greater tuberosity (AGT). Logistic regression and ROC analyses were used. ROC curves, calibration plots, and decision curves were drawn on the training and validation sets. Results: According to logistic regression analysis, the ratio of supraspinatus muscle thickness was statistically significant (OR: 0.80; 95% CI: 0.70-0.92; p < 0.01), and it was an independent factor for evaluating the presence or absence of GHS. An AUC of 0.906 (95% CI, 0.802-1.000) was found in the training set; meanwhile, the AUC in the validation set was 0.857 (95% CI, 0.669-1.000), indicating good performance. According to the training set ROC curve, the most effective statistical threshold was 93%, with a sensitivity of 84% and a specificity of 96%. Discussion: The ratio of supraspinatus muscle thickness is a valuable criterion for evaluating GHS risk, supporting targeted rehabilitation interventions.

Integrating Ultrasound-Guided Multifidus Injections with Repeated Peripheral Magnetic Stimulation for Low Back Pain: A Feasibility Study.

Background: Low back pain is a globally prevalent musculoskeletal issue. Repetitive peripheral magnetic stimulation (rPMS) is emerging as a promising modality for managing musculoskeletal pain, while ultrasound-guided lumbar facet/multifidus injections are a potential therapeutic option for low back pain. This study explores the feasibility of combining these two treatments for managing low back pain. Materials and Methods: Ultrasound-guided injections were administered using 5 mL of 50% dextrose and 5 mL of 1% lidocaine. Bilateral injections targeted the L4/L5 and L5/S1 facet joints with 1 mL at each site, and the remaining 8 mL was distributed over the multifidus muscles using peppering techniques. Following injections, rPMS therapy was conducted with the TESLA Stym® device, targeting the bilateral lumbosacral region over 12 sessions. Pain intensity was measured using the visual analog scale (VAS), and disability was assessed with the Oswestry disability index (ODI) at baseline, after six sessions, and after 12 sessions of rPMS. Results: Three participants were enrolled. Baseline VAS and ODI scores were 8.33 ± 0.29 cm and 49.63 ± 1.28%, respectively. After six rPMS sessions, VAS and ODI scores changed to 4.33 ± 3.75 cm and 21.48 ± 19.42%, respectively. After 12 sessions, VAS decreased to 0.83 ± 1.44 cm and ODI to 5.19 ± 8.98%. Significant differences were observed between baseline and final assessments. Conclusion: Combining ultrasound-guided lumbar facet/multifidus injections with rPMS shows promise for treating low back pain. However, long-term efficacy and comparison with conventional treatments require further investigation through prospective randomized controlled trials.

Comparison of sEMG activity of submental muscles between the head-lift exercise, tongue-press exercise and the head extension tongue-press exercise in healthy young adults.

BACKGROUND: Swallowing is a complex function that requires precise coordination between different muscles. Weakness in submental muscles can lead to complications such as pharyngeal residue and aspiration. Therefore, exercise interventions targeting these muscles, such as the Head-Lift Exercise (HLE), are clinically important but pose challenges. OBJECTIVE(S): This study aimed to compare the myoelectric activity of submental muscles during traditional Head-Lift Exercise (HLE), Tongue-Press Exercise (TPE) and Head Extension Tongue-Press Exercise (HETPE), providing potential alternatives to HLE. METHODS: Thirty healthy volunteers (22 females and 8 males, mean age 25.63 ± 5.27 years) participated in this cross-sectional study. Surface electromyography (sEMG) recorded activity of the submental muscles bilaterally during HLE, TPE and HETPE. Participants performed each manoeuvre for 14 s, repeated three times in a counterbalanced order. Statistical analyses assessed differences in mean, maximum and median frequency of the sEMG signals among manoeuvres using repeated-measures analysis of variance (RM-ANOVA). The experienced irritation levels by participants during manoeuvres were also compared by the Friedman test. RESULTS: HETPE exhibited significantly higher maximum sEMG activity compared to HLE and TPE (p < .05). Mean sEMG activity was significantly increased during HETPE compared to TPE. Median frequency was significantly lower during HETPE compared to the two other exercises, indicating greater muscle fatigue. Participants reported similar levels of irritation for HLE and HETPE, and significantly lower levels during TPE. CONCLUSION: These results indicate that HETPE is effective in activating and strengthening submental muscles, potentially serving as a viable alternative to HLE without added difficulty. Further research is recommended to assess the long-term impacts on swallowing physiology in patients with dysphagia.

[Ocular myasthenia gravis]. / Glaznaya forma miastenii gravis.

Myasthenia gravis is an autoimmune disease characterized by muscle weakness and pathological fatigue due to autoaggressive phenomena with the formation of antibodies directed against various structures of the neuromuscular synapse. In most patients, the disease begins with the involvement of extraocular muscles, presenting with symptoms such as intermittent ptosis of the upper eyelid and/or binocular diplopia. In 15% of cases, clinical manifestations are limited to impairment of the levator palpebrae superioris and extraocular muscles, characteristic of the ocular form of myasthenia gravis. Specialists often encounter challenges in diagnosing this form, as serological and electrophysiological studies may be uninformative, necessitating diagnosis based on patient history and clinical picture. This literature review outlines the key aspects of the pathogenesis, clinical manifestations, methods of diagnosis and treatment of ocular myasthenia gravis.

Relationship between craniofacial skeletal patterns and anatomic characteristics of masticatory muscles: a systematic review and meta-analysis.

BACKGROUND: The anatomic characteristics of the masticatory muscles differ across craniofacial skeletal patterns. OBJECTIVE: To identify differences in the anatomic characteristics of masticatory muscles across different sagittal and vertical craniofacial skeletal patterns. ELIGIBILITY CRITERIA: Studies measuring the thickness, width, cross-sectional area (CSA), volume and orientation of masticatory muscles in healthy patients of different sagittal (Class I, Class II, and Class III) and/or vertical (normodivergent, hypodivergent, and hyperdivergent) patterns. INFORMATION SOURCES: Unrestricted literature searches in 8 electronic databases/registers until December 2023. RISK OF BIAS AND SYNTHESIS OF RESULTS: Study selection, data extraction, and risk of bias assessment with a customised tool were performed independently in duplicate. Random-effects meta-analysis and assessment of the certainty of clinical recommendations with the GRADE approach were conducted. RESULTS: 34 studies (37 publications) were selected with a total of 2047 participants and data from 16 studies were pulled in the meta-analysis. Masseter muscle thickness in relaxation was significantly greater by 1.14 mm (95% CI 0.74-1.53 mm) in hypodivergent compared to normodivergent patients while it was significantly decreased in hyperdivergent patients by - 1.14 mm (95% CI - 1.56 to - 0.73 mm) and - 2.28 mm (95% CI - 2.71 to - 1.85 mm) compared to normodivergent and hypodivergent patients respectively. Similar significant differences were seen between these groups in masseter muscle thickness during contraction as well as masseter muscle CSA and volume. Meta-analyses could not be performed for sagittal categorizations due to insufficient number of studies. CONCLUSIONS: Considerable differences in masseter muscle thickness, CSA and volume were found across vertical skeletal configurations being significantly reduced in hyperdivergent patients; however, results should be interpreted with caution due to the high risk of bias of the included studies. These variations in the anatomic characteristics of masticatory muscles among different craniofacial patterns could be part of the orthodontic diagnosis and treatment planning process. REGISTRATION: PROSPERO CRD42022371187 .

Deep learning-based structure segmentation and intramuscular fat annotation on lumbar magnetic resonance imaging.

Background: Lumbar disc herniation (LDH) is a prevalent cause of low back pain. LDH patients commonly experience paraspinal muscle atrophy and fatty infiltration (FI), which further exacerbates the symptoms of low back pain. Magnetic resonance imaging (MRI) is crucial for assessing paraspinal muscle condition. Our study aims to develop a dual-model for automated muscle segmentation and FI annotation on MRI, assisting clinicians evaluate LDH conditions comprehensively. Methods: The study retrospectively collected data diagnosed with LDH from December 2020 to May 2022. The dataset was split into a 7:3 ratio for training and testing, with an external test set prepared to validate model generalizability. The model's performance was evaluated using average precision (AP), recall and F1 score. The consistency was assessed using the Dice similarity coefficient (DSC) and Cohen's Kappa. The mean absolute percentage error (MAPE) was calculated to assess the error of the model measurements of relative cross-sectional area (rCSA) and FI. Calculate the MAPE of FI measured by threshold algorithms to compare with the model. Results: A total of 417 patients being evaluated, comprising 216 males and 201 females, with a mean age of 49 ± 15 years. In the internal test set, the muscle segmentation model achieved an overall DSC of 0.92 ± 0.10, recall of 92.60%, and AP of 0.98. The fat annotation model attained a recall of 91.30%, F1 Score of 0.82, and Cohen's Kappa of 0.76. However, there was a decrease on the external test set. For rCSA measurements, except for longissimus (10.89%), the MAPE of other muscles was less than 10%. When comparing the errors of FI for each paraspinal muscle, the MAPE of the model was lower than that of the threshold algorithm. Conclusion: The models demonstrate outstanding performance, with lower error in FI measurement compared to thresholding algorithms.

Mechanical drivers of intrinsic foot muscle for maximum toe flexor strength in upright standing across different body size.

This study aimed to evaluate maximum toe flexor strength, foot arch height, intrinsic toe flexor muscle size and foot arch stiffness among individuals with different body sizes, and to compare these variables between sitting and standing positions. Maximum toe flexor strength in sitting and standing, and intrinsic foot muscle thicknesses (flexor hallucis brevis: FHB, flexor digitorum brevis: FDB, abductor hallucis: AH and quadratus plantae: QP), were measured using a toe grip dynamometer and a B-mode ultrasound in healthy young men. FHB was thicker than AH, FDB and QP, AH was thicker than FDB and QP, and no significant difference was found between FDB and QP. Toe flexor strength was correlated with FHB and AH, and foot arch height was correlated with FHB. Toe flexor strength was greater in standing than in sitting. Stepwise multiple regression analysis identified FHB and AH as determinants of toe flexor strength in standing, and the relative muscle strength values per body weight in standing were determined by QP, foot arch index and foot arch stiffness. Overweight individuals had a decreased rate of increase in relative toe flexor strength compared to normal individuals. These results suggest that a large muscle thickness of intrinsic foot muscle a key contributor to toe flexor strength. Moreover, toe flexor muscle in upright standing could have the potential to generate force independently of intrinsic foot muscle size, but obese individuals who chronically put weight on their feet might impair the force amplification mechanism in upright standing.

New complex cell junctions in and around the intervertebral discs discovered using autoantibodies from patients affected by endemic pemphigus foliaceus in El Bagre, Colombia, South America.

BACKGROUND: Traditionally, the intervertebral disks' (IVD) nucleus pulposus (NP) and annulus fibrosus (AF) are considered to have few cellular components and cell junctions. Patients affected by a new variant of endemic pemphigus foliaceus in El Bagre, Colombia, experience back pain in the spinal areas of the lower and upper back. Here, we investigate the reactivity of the patient's autoantibodies to structures in and around the IVDs at the cellular level. METHODS: We first administered a questionnaire and performed a medical examination. We then tested for autoreactivity against IVDs by indirect immunofluorescence, confocal microscopy, and reflectance confocal microscopy using bovine and human tissues as antigen sources. We tested 45 sera from patients affected by the disease and 45 control sera from the endemic area matched by age, gender, demographics, and work activity. RESULTS: Most of the patient sera revealed polyclonal antibodies against newly discovered cell junctions in the NP and AF, including their translamellar cross-bridges. Additional reactivities were detected against cell junctions in the spinal cord neurons, paraspinal nerves, blood vessels, anterior and posterior longitudinal ligaments, and paraspinal skeletal muscles. The reactivities of the patient's autoantibodies co-localized with those of commercially available antibodies to desmoplakins I-II, armadillo repeat gene deleted in velo-cardio-facial syndrome, plakophilin-4, and myocardium-enriched zonula occludens-1-associated protein (p < 0.001). CONCLUSIONS: We discovered novel complex cell junctions in the IVDs using patients' autoantibodies. These discoveries open a new chapter in the knowledge of IVD, representing a breakthrough pertinent to many diseases.