Superficial Muscles Research Articles

A comparison of electromyography techniques: surface versus intramuscular recording.

This review is a comprehensive guide for electromyography (EMG) researchers, providing a comparison of skin EMG recording (surface EMG: sEMG and high-density sEMG: HD-sEMG) and intramuscular EMG recording (multi-motor unit-MMU and single motor unit electromyography-SMU). We delve into the nuances of techniques, highlighting their strengths and limitations in quantifying muscle activation during dynamic and static conditions. We first examine how EMG signals change with time, focussing on the interplay between motor unit synchronisation and signal amplitude. The review then explores the impact of electrode placement on signal quality. We further discuss the challenges of signal cancellation, crosstalk from neighbouring muscles, and motion artifacts, which can significantly affect signal integrity. Finally, we address the temporal changes in electrode impedance and its implications for data interpretation. Our analysis proposes that specific research objectives should guide the choice amongst sEMG, HD-sEMG, SMU and MMU. MMU, which records the peak counts of individual motor unit action potentials from a localised muscle area, is particularly suited for studying deep or small muscles during static and dynamic activities. Its high sensitivity to motor unit recruitment and discharge rates minimises the impact of factors such as signal cancellation and motion artefacts. Conversely, sEMG is well-suited for short-duration, isometric assessments of large, superficial muscles. HD-sEMG helps study single motor unit properties under isometric conditions. SMU is particularly suited for studying neuronal networks between stimulated sites and motor neurons. This review aims toprovideresearchers with the information to select the most appropriate EMG technique for their investigations.

Spatial-Temporal Structure Features of Muscle Synergies During Profiling Elements Implementation in Rhythmic Gymnastics

The article presents an analysis of the muscle synergies involved in making ball throws in different directions and from different starting positions. The study involved 6 highly qualified athletes engaged in rhythmic gymnastics. Electromyograms of the superficial muscles of the upper extremities and trunk were recorded synchronously during the movements, as well as video capture of the movements of body segments. Synergy parameters were extracted from the recorded signals using factor analysis using the principal component method. It has been established that individuals who have mastered a complex motor skill can demonstrate similar motor control strategies. This is manifested in the structuring of intermuscular interaction in the form of two general modules, the degree of involvement of muscles in which is highly similar in the implementation of different motor tasks. The first muscle module implements active movement of the upper limb by jointly activating the muscles of the forearm, shoulder and upper shoulder girdle, and also provides stabilization of the position of the trunk by synchronizing the activity of the muscles of the back and abdomen. The second muscle module is specific and is mainly associated with high involvement in the synergy of the muscles of the upper shoulder girdle and forearm for the implementation of exercises performed without visual control, or from starting positions that limit the mobility of certain parts of the body. Thus, the solution to the problem of coordination of many elements of the motor system may consist not only in reducing the number of executive organs – muscles involved in control, but also in organizing control variables in the form of modules at the kinematic level and their stabilization through muscle synergies.

Ultrasound-Guided Deep Serratus Plane Block in Cat Cadavers (Felis catus): A Description of Dye and Contrast Media Distribution.

The serratus plane block is an ultrasound-guided anaesthetic technique that aims to provide analgesia to the lateral thoracic wall cranial to the 8th rib. This block can be performed in a superficial (between the latissimus dorsi and the serratus ventralis thoracis (SVT) muscles) or deep plane (between the intercostales externi and the SVT muscles). This study aimed to assess the distribution and nerve staining of a mixture of 0.4 mL kg-1 of methylene blue and iopromide 50:50 performing a deep serratus plane (DSP) block at the level of the 5th rib. We hypothesise that this technique would be feasible and could stain the rami cutanei laterales (RCL) of the intercostales nerves cranial to the 8th rib in cat cadavers. This study was divided into two phases. Phase 1 consisted of an anatomical study of the thoracic wall (2 cadavers). Phase 2 consisted of the ultrasound-guided injection of the aforementioned mixture and the assessment of its distribution by computed tomography and anatomical dissection (12 cadavers). Contrast media spread a median of 5.5 (2.5-7.5) intercostal spaces. The dye stained a median of 3 (0-5) RCL, affecting RCL 2 (17.39%), RCL 3 (57.17%), RCL 4 (78.26%), RCL 5 (91.30%), RCL 6 (78.26%), and RCL 7 (8.70%) within the DSP. Occasionally, the rami dorsales laterales and the thoracicus longus nerve were stained. Based on these findings, the DSP block performed with a volume of 0.4 mL kg-1 of an anaesthetic could provide analgesia in the area innervated from T4 to T6.

Neck muscle stiffness during craniocervical flexion under functional upper extremity conditions in patients with chronic non-specific neck pain: A shear-wave elastography study

ObjectiveThe primary objective of the present study was to examine the differences and patterns of change in the neck extensor (NE) muscle stiffness during the Cranio-cervical flexion (CCF) task under different functional conditions of the upper extremity between CNSNP participants and asymptomatic controls. MethodsIn the current case-control study, 25 participants with CNSNP and 25 asymptomatic controls were recruited. The stiffness of the superficial (i.e., upper trapezius, splenius capitis, and semispinalis capitis) and deep (i.e., semispinalis cervicis and multifidus) NE muscles was measured at prone resting, sitting resting, and during the CCF task in different functional conditions of upper extremity using shear wave elastography. ResultsThe findings showed that there was a significant main effect of condition in all NE muscles (P < 0.05), as well as a significant main effect of the group on the stiffness of superficial neck muscles (P < 0.05), indicating higher muscle stiffness in participants with CNSNP compared to the control group. There was no significant group-by-condition interaction effect on the stiffness of NE muscles (P > 0.05), except for the upper trapezius muscle (P = 0.00), indicating a different pattern of stiffness changes compared to the other muscles. ConclusionsIndividuals with CNSNP exhibited significantly greater stiffness in the superficial neck extensor muscles compared to healthy controls. Furthermore, the CCF task performed under functional upper extremity conditions, which includes bilateral shoulder scaption and shoulder abduction-external rotation while seated, resulted in increased stiffness of the NE muscles. Additionally, participants with CNSNP exhibited a higher magnitude of stiffness changes in the upper trapezius muscle across different conditions.

An Ultrasonographic Analysis of the Deep Inferior Tendon in the Masseter Muscle: Implications for Botulinum Toxin Injections.

(1) Background: With the increasing aesthetic pursuit of facial features, the clinical use of Botulinum Toxin Type A (BoNT-A) injections for masseter hypertrophy has been on the rise. However, due to variations in masseter muscle structure and differences in clinicians' injection techniques, blind injections may lack precision, potentially compromising treatment accuracy and increasing the risk of complications. (2) Objectives: The study aims to use ultrasonography to detail the deep inferior tendon (DIT) within the masseter muscle in a young Chinese cohort, refine its classification, analyze muscle belly thickness and variations across groups, and propose a customized ultrasound-guided BoNT-A injection protocol. (3) Methods: Ultrasound imaging was used to observe the bilateral masseter muscles at rest and during clenching. The features of the DIT were classified from these images, and the thickness of the masseter's distinct bellies associated with the DIT types was measured in both states. (4) Results: The study cohort included 103 participants (27 male, 76 female), with 30 muscles in the normal masseter group and 176 muscles in the hypertrophy group. The DIT was categorized as Type A, B (subtypes B1, B2), and C. The distribution of these types was consistent across normal, hypertrophic, and gender groups, all following the same trend (B > A > C). In hypertrophy, Type B1 showed uniform thickness across masseter bellies, B2 presented with a thinner intermediate belly, and Type C had mainly superficial muscle enlargement. Changes in muscle thickness during clenching were noted but not statistically significant among different bellies. (5) Conclusions: The study evidences individual variation in the DIT, highlighting the importance of precise DIT classification for effective BoNT-A injections. A tailored ultrasound-guided BoNT-A injection strategy based on this classification may enhance safety and efficacy of the therapy.

MRI-based assessment paraspinal extensor muscle fatty infiltration in acute cervical spinal cord injury patients - a retrospective study

BackgroundThe effect of fat infiltration in the paraspinal muscles on cervical degenerative disease has been confirmed by multiple studies. However, little is known about fat infiltration in the paraspinal extensors in patients with acute cervical spinal cord injury (SCI). This study aimed to investigate the difference in paraspinal extensor fatty infiltration between patients with acute cervical SCI and healthy controls, and to further explore the protective role of the paravertebral extensor muscles in patients with cervical SCI.MethodsA total of 50 patients with acute cervical SCI admitted to the emergency department from January 2019 to November 2023 were retrospectively analyzed, including 26 males and 24 females, with an average age of 59.60 ± 10.81 years. A control group of 50 healthy middle-aged and elderly individuals was also included, comprising 28 males and 22 females, with an average age of 55.00 ± 8.21 years. Cervical spine magnetic resonance imaging (MRI) was used to measure the cross-sectional areas of the superficial and deep cervical extensor muscles, the corresponding vertebral body cross-sectional areas, and the fat area within the superficial and deep extensor muscle groups using Image J software. Differences between the two groups were compared, and the cervical SCI patients were further analyzed based on the severity of the spinal cord injury and gender differences.ResultsThe deep fatty infiltration ratio (DFIR) and superficial fatty infiltration ratio (SFIR) at C4-C7 in the cervical SCI group were significantly higher than those in the control group (P < 0.001). The cross-sectional area of the functional deep extensor area (FDEA) relative to the vertebral body area (VBA) and the cross-sectional area of the functional superficial extensor area (FSEA) relative to the VBA at the C5 and C6 levels in the cervical SCI group were significantly lower than those in the control group (P < 0.001, P < 0.001, P = 0.034, P = 0.004 respectively). Among the cervical SCI patients, the cross-sectional areas of the deep extensor area (DEA) and the superficial extensor area (SEA) in males were significantly higher than those in females (P < 0.001). At the C6 and C7 levels, the FDEA/VBA and FSEA/VBA ratios in the male group were higher than those in the female group (P = 0.009, P = 0.022, P = 0.019, P = 0.005, respectively).ConclusionPatients with acute cervical SCI exhibit significantly higher fatty infiltration and a greater degree of paravertebral extensor muscle degeneration compared to healthy controls. This finding underscores the importance of the paravertebral extensor muscles in the context of cervical SCI and may guide future therapeutic strategies.

Lower Extremity Muscle Volume in Unilateral and Bilateral Patellofemoral Pain: A Cross-Sectional Exploratory Study Including Superficial and Deep Muscles.

Existing patellofemoral pain (PFP) literature has primarily been focused on quadriceps muscle volume, with limited attention given to the deep and superficial muscle volume of the lower limbs in individuals with unilateral and bilateral PFP. In this paper, we aim to fill this gap. To explore superficial and deep lower extremity muscle volume in women with unilateral or bilateral PFP compared with a normative database of pain-free women. Cross-sectional study. University imaging research center. Twenty women with PFP (10 unilateral and 10 bilateral) and 8 pain-free women from a normative database. We quantified lower extremity muscle volume via 3.0-T magnetic resonance imaging. Two separate 1-way analyses of variance were performed: (1) unilateral PFP (painful versus nonpainful limb) versus pain-free control groups and (2) bilateral PFP (more painful versus less painful limb) versus pain-free control groups. We observed no differences in age and body mass index across groups (P > .05). Compared with the pain-free group, the unilateral and bilateral PFP groups had bilaterally smaller volumes of the anterior (iliacus: P ≤ .0004; d range, 2.12-2.65), medial (adductor brevis, adductor longus, gracilis, and pectineus: P ≤ .02; d range, 1.25-2.48), posterior (obturator externus, obturator internus, and quadratus femoris: P < .05; d range, 1.17-4.82), and lateral (gluteus minimus: P ≤ .03; d range, 1.16-2.09) hip muscles and knee extensors (rectus femoris: P ≤ .003; d range, 1.67-2.16) and flexors (long and short head of the biceps femoris: P ≤ .01, d range, 1.56-1.93). Women with unilateral and those with bilateral PFP displayed less volume of multiple superficial and deep muscles of the bilateral hips and knees than pain-free women. Interventions should bilaterally target lower limb muscles when treating PFP, and hypertrophy exercises for specific muscles should be explored to increase choices for intervention.

Evolving Dynamics of Neck Muscle Activation Patterns in Dental Students: A Longitudinal Study.

Cervical pain has been linked to increased motor unit activity, potentially associated with the initiation and progression of chronic neck pain. Therefore, this study aimed to compare the time-course changes in cervical superficial muscle activation patterns among dental students with and without neck pain throughout their initial semester of clinical training. We used an online Nordic Musculoskeletal Questionnaire for group allocation between neck pain (NP) (n = 21) and control group (CG) (n = 23). Surface electromyography (sEMG) of the sternocleidomastoid and upper bilateral trapezius was recorded before starting their clinical practice and after their first semester while performing a cranio-cervical flexion test (CCFT) in five increasing levels between 22 mmHg and 30 mmHg. After the first semester, both the CG (p < 0.001) and NP (p = 0.038) groups showed decreased sternocleidomastoid activation. The NP group exhibited a concomitant increase in upper trapezius coactivation (p < 0.001), whereas the muscle activation pattern in asymptomatic students remained unchanged (p = 0.980). During the first semester of clinical training, dental students exhibited decreased superficial flexor activity, but those with neck pain had increased co-contraction of the upper trapezius, likely to stabilize the painful segment. This altered activation pattern could be associated with further dysfunction and symptoms, potentially contributing to chronicity.

Establishing a Mouse Model of Surgical Vocal Fold Injury.

Animal models of vocal fold (VF) surgical injury and scar formation provide insight into the wound healing process. The purpose of this study was to establish an alternative model of surgical injury to the mouse VF using materials commonly available in most research laboratories or for purchase and to investigate wound healing of the epithelium (EP) and lamina propria (LP). Mice were anesthetized by isoflurane gas delivery and positioned on a platform so that the larynx could be observed using a laryngoscope and dissection microscope. Unilateral VF injury was created using a wire brush. Mice were euthanized and the larynx evaluated 1-, 3-, 5-, 7-, 14-, and 28-days following injury. Histological and immunofluorescent analysis was used to evaluate thickness of the EP, LP area, proliferative (Ki67+) and basal cells (p63+) in the EP, and collagen III content in the LP. The depth of injury reached the superficial thyroarytenoid muscle on Day 1. The thickness of the EP of the injured VF was increased on Days 3 and 5, and the LP area was increased on Days 3, 5, and 7 as compared with the uninjured VF. Ki67+ and p63+ cells were increased on Day 3 and collagen III content was increased on Days 5 and 28 as compared with the uninjured VF. We successfully established an alternative method of creating unilateral VF injury in the mouse. This method will be useful for future research regarding VF surgical injury and wound healing. N/A Laryngoscope, 2024.

Gauging force by tapping tendons? Inaccurately in the human patellar tendon

Accurately estimating in vivo tendon load non-invasively remains a major challenge in biomechanics, which might be overcome by shear-wave tensiometry. Shear-wave tensiometry measures the speed of mechanically induced tendon shear waves by skin-mounted accelerometers. To gauge the feasibility and accuracy of this novel technique, we obtained patellar tendon shear wave speeds via shear-wave tensiometry during sustained or ramp voluntary contractions of the knee extensors in two experiments (n = 8 in both). In experiment one, participants produced a constant knee extension torque of ∼ 50 Nm at five different knee joint angles (i.e. variable tendon load), which resulted in estimated patellar tendon forces between 1005 ± 6N and 1182 ± 16 N. However, wave speed squared did not correlate with estimated tendon force within participants (rrm(31) = -0.19, p = 0.278). In experiment two, averaged correlation coefficients between normalized wave speed squared and torque of maximal and submaximal voluntary contractions across participants ranged between r = 0.43 and r = 0.94, while the time-varying correlation between these normalized signals ranged from r = -0.99 to r = 1.00. Further, the mean absolute errors (MAEs) between normalized wave speed squared and normalized torque across participants ranged between 0.03 and 0.54, which were larger than the MAEs between normalized torque and normalized summed EMG amplitude from the superficial quadriceps muscles (0.03–0.54 versus 0.06–0.26, respectively). In conclusion, there was no simple relation between shear wave speed squared and patellar tendon load, which severely limits the feasibility of shear-wave tensiometry for accurately estimating in vivo tendon load at the knee joint.

Automatic anal sphincter integrity detection from ultrasound images via convolutional neural networks.

The anal sphincter complex comprises the anal sphincter and the U-shaped deep and superficial puborectalis muscle. As an important supporting structure of the posterior pelvic floor, together with its surrounding tissues and muscles, the anal sphincter complex maintains the normal physiological functions of defecation and continence. The plane required for diagnosing anal sphincter injury and the diagnosis of anal sphincter integrity through pelvic floor ultrasound are highly dependent on sonographers' experience. We developed a deep learning (DL) tool for the automatic diagnosis of anal sphincter integrity via pelvic floor ultrasound. A 2D detection network was trained to detect the bounding box of the anal sphincter. The pelvic floor ultrasound image and its corresponding oval mask were input into a 2D classification network to determine the integrity of the anal sphincter. The average precision (AP) and intersection over union (IoU) were used to evaluate the performance of anal sphincter detection. Receiver operating characteristic (ROC) analysis was used to evaluate the performance of the classification model. The Pearson correlation coefficients (r values) of the topmost and bottommost layers detected by the CNN and sonographers were 0.932 and 0.978, respectively. The best DL model yielded the highest area under the curve (AUC) of 0.808 (95% CI: 0.698-0.921) in the test cohort. The results from the CNN agreed well with the diagnostic results of experienced sonographers. We proposed, for the first time, a CNN to obtain the plane required for diagnosing anal sphincter injury on the basis of pelvic floor ultrasound and for preliminarily diagnosing anal sphincter injury.

Preinjection With Ligation-Assisted Endoscopic Mucosal Resection for Barrett's Dysplasia and Early Esophageal Adenocarcinoma: Characteristic Histological Features of the Depth of Resection.

Endoscopic mucosal resection (EMR) is an established technique for the diagnosis and treatment of high-grade dysplasia (HGD) and early esophageal adenocarcinoma (EAC) in Barrett's esophagus. Submucosal preinjection is not universally used or generally recommended when performing routine ligation-assisted EMR. Prior studies, however, have demonstrated evidence of at least superficial muscle injury on ligation-assisted EMR without submucosal injection. There are limited published data supporting any potential benefit of submucosal preinjection. Our aim was to review this technique and determine the rate of any degree of muscle injury in patients with Barrett's HGD and EAC treated with submucosal preinjection before ligation-assisted EMR. Patients undergoing submucosal preinjection before ligation-assisted EMR for Barrett's esophagus at a single institution between 2012 and 2016 were identified. Data were collected regarding patient demographics and medical history, endoscopy and histopathology findings, adverse events, and subsequent outcomes. All EMR specimens were reviewed by an expert gastrointestinal pathologist. One hundred fifty consecutive EMR procedures were performed on 70 patients. Of 70 patients, 85.7% of patients were men, with a median age of 68 years. EAC was identified in 75 specimens (50%) and HGD in 44 specimens (29.3%). Deep resection margins were clear of adenocarcinoma in all specimens. Muscularis propria was not identified in any of the 150 specimens. There were no cases of post-EMR perforation. Preinjection before ligation-assisted EMR achieved complete excision with histologically clear margins, without histological evidence of any inadvertent muscularis propria.

Ứng dụng tiêm Botulinum Neurotoxin dưới hướng dẫn của siêu âm và điện cơ trong điều trị loạn trương lực cơ cổ: Ca lâm sàng

Dystonia is a movement disorder characterized by persistent or intermittent muscle contractions, involuntary, creating repetitive and/or abnormal postures and movements. Dystonic movements result in characteristic twisting or tremor patterns. Dystonia often begins or worsens with intentional movements, combined with excessive muscle activation. Dystonia is classified according to the affected body regions: focal dystonia, segmental dystonia, multifocal dystonia, hemidystonia, and generalized dystonia. Anterocollis is a type of cervical dystonia, caused by persistent, repetitive contractions of neck muscle groups, leading to excessive neck flexion. Anterocollis is described in the context of movement disorders in Parkinson’s syndrome (Parkinson’s disease, multiple system atrophy, etc.). Treatment of dystonia is primarily symptomatic: medications, Botulinum Neurotoxin (BoNT) injections, surgery, and physical therapy. Among these, BoNT injections are considered the first choice for focal or segmental dystonia.Botulinum Neurotoxin acts at the neuromuscular junction, leading to muscle paralysis. BoNT injections require injection equipment, surface disinfection, and determination of the injection site based on clinical landmarks. Some deep and difficult injections require specialized techniques such as electromyography (EMG) and ultrasound. In the case of anterocollis, BoNT is often applied to both superficial and deep muscles. To achieve effectiveness and limit complications during and after injection, practitioners often use combined EMG and ultrasound techniques. We present a clinical case to illustrate the value of using BoNT injections under the simultaneous guidance of EMG and ultrasound in treating anterocollis at the Neurology Department of Hanoi Medical University Hospital.

Skeletal Muscle Complex Between the Vagina and Anal Canal: Implications for Perineal Laceration.

The anatomy of the skeletal muscles located between the vagina and anus is important during complex obstetric laceration reconstructions. We aimed to clarify the composition of skeletal muscles located between the vagina and anal canal and their three-dimensional configuration relevant to perineum repair. This observational study involved ten female cadavers. An anatomical dissection was performed to observe the muscles around the vagina and anal canal. Immunohistological analysis of the midsagittal section was performed to clarify the composition of the muscles, and dissection was performed to correspond to the cross-section. Wide-range serial sectioning and three-dimensional reconstruction were used to support these findings histologically and visualize the three-dimensional arrangement. The region between the vagina and anal canal included the anterior part of the external anal sphincter, superficial transverse perineal muscle approaching from the lateral side, and levator ani, located cranially. They converge three-dimensionally in the median from each direction, forming a muscle complex between the vagina and anal canal. The medial region between the vagina and anal canal in those giving birth includes a skeletal muscle complex formed by the confluence of the external anal sphincter, anterior bundle of the levator ani, and superficial transverse perineal muscle. In cases of severe perineal lacerations, these muscles could be injured. The anatomical knowledge that a part of the levator ani forms a muscle sling anterior to the anal canal is particularly important for obstetricians and gynecologists repairing obstetric lacerations and treating pelvic floor disorders.

Evaluation of infrared thermography, arterial Doppler ultrasound, and Doppler echocardiography in healthy adult dogs exposed to a single session of Whole-body vibration at different frequencies

This study aimed to evaluate the infrared thermography, arterial Doppler ultrasound, and Doppler echocardiography in healthy adult dogs exposed to a single Whole-body vibration (WBV) at different frequencies. Sixteen (16) healthy crossbreed dogs males of ages 1 to 5 years, weighing 16.3 to 24.5 kg were enrolled in the study. The dogs were exposed to a single WBV session at frequencies of 30 Hz (5 min), 40 Hz (5 min), and 50 Hz (5 min) with intervals between each frequency exposure of 10 min. The cutaneous temperature, arterial Doppler ultrasound, and Doppler echocardiography were evaluated 10 min before the WBV session, between each frequency, and 1 min after the last frequency. The cutaneous temperature of the regions of the superficial gluteal muscle and biceps femoris muscle of both hind limbs was obtained with an infrared camera. Resistive indexes of carotid and femoral arteries were determined using Doppler ultrasound, and Doppler echocardiography was used to assess the end-systolic volume and end-diastolic volume, heart rate, aortic blood flow velocity, and pulmonary artery flow velocity. Clinical parameters, complete blood count, and serum biochemical (alanine aminotransferase, creatinine, and creatine phosphokinase) were evaluated 10 min before and 60 min after the end of the WBV session. Statistically significant differences were not found in any of the variables among the time points. In conclusion, the protocol of increasing vibration frequencies (30, 40, and 50 Hz) at short-period WBV can be considered appropriate since no change occurred in the parameters evaluated.

Predicting Forces in the Components of the Human Upper Limb through Multibody Dynamics and Optimization Techniques

Abstract An accurate model of the human upper limb is crucial for various applications, including prosthetic development, optimizing ergonomics, and rehabilitation. The novelty of this research is to obtain a model that predicts the forces of muscles, ligaments, and joint reactions under any loading conditions, thereby enabling the prediction of musculoskeletal forces during different daily activities. For this, a multibody three-dimensional dynamic model of the human upper limb is presented to study the upper limb musculoskeletal system. The model comprises 35 muscle elements, 11 ligaments, and 7 joints. Thirty equations of motion with 73 unknowns were obtained using Newton’s second law of motion. The Ariel Performance Analysis System (APAS) was utilized to record and analyze the motion of 16 bony landmarks using 8 digital video cameras with a sampling rate of 100 frames per second. The genetic algorithm (GA) and particle swarm optimization (PSO) are used to solve the redundant force problem of the model. The GA and PSO are implemented with two distinct objective functions; the first is the sum of the squared muscles’ stresses. The second one is the sum of the muscles’ energy consumption. The model was validated through EMG recordings of eight superficial muscles and with the available data in the literature. The results show that the inclusion of the ligaments at the GH and elbow joints in addition to the trapezoid and conoid ligaments in the model led to a more precise prediction of the muscles’ force. The PSO shows more accuracy and smoothness of the predicted muscles’ force, despite the GA taking more running time and requiring significant memory resources. The model also revealed that there is no great difference in the predicted muscles’ force when using any of the two cost functions.

Assessment of the effects of direct myofascial release in the lateral gastrocnemius muscle of tennis athletes using ShearWave™ elastography

ObjectivesThe purpose of the present study was to utilize ShearWave™ Elastography to assess tissue stiffness by measuring shear wave speed before and after applying the direct Myofascial release (MFR) technique to the lateral gastrocnemius muscle of competitive tennis athletes. MethodsShear wave speed values were measured in the regions of interest within the lateral gastrocnemius fascia and muscle areas from the elastographic images. Measurements were taken in three different situations: before, immediately after and 5 min after MFR protocol. Subsequently, the results from each situation were statistically compared. ResultsThe protocol was administered to a group of eighteen tennis players with a mean age of 18 ± 1.23 years. The shear wave speed values increased for both fascia and muscles sites, after applying the MFR technique: From 3.01 ± 0.64 to 3.33 ± 0.86 m/s in the deep fascia and from 2.23 ± 0.41 to 2.57 ± 0.51 m/s in superficial fascia. In the deep and superficial muscles sites the increases were from 4.12 ± 0.95 to 4.40 ± 1.22 m/s, and from 2.94 ± 0.71 to 3.38 ± 0.95 m/s, respectively. ConclusionThis study showed that after the myofascial manipulation in tennis athletes, the lateral gastrocnemius muscle and fascia tissues stiffness increased, according to elastography, and possible mechanisms were discussed. ShearWave™ Elastography could be utilized to assess the acute effects of applying a direct myofascial release (MFR) technique.

Baseline masticatory muscles' performance may predict pain relief in temporomandibular disorders.

To compare masticatory muscles' recruitment in patients with temporomandibular disorders and asymptomatic control subjects. To evaluate if the masticatory muscles' recruitment pattern may predict symptoms' improvement after temporomandibular disorders treatment. Standardized surface electromyography of anterior temporalis and superficial masseters muscles were recorded and compared at baseline in 26 patients with arthrogenous temporomandibular disorders (study group) and 26 asymptomatic subjects (control group). The study group was treated pharmacologically and by means of five arthrocentesis sessions. Pre-, during-, and post-treatment pain and mandibular function were assessed and compared among timepoints. Clinical improvement in terms of pain and mandibular function was correlated with pre-treatment standardized surface electromyography values. Temporomandibular disorders patients showed improved maximum mouth opening and pain during and after treatment with arthrocentesis compared to baseline (T-test p < 0.01). Standardized surface electromyography values were significantly different in temporomandibular disorders subjects compared to controls (T-test p < 0.05). Improvement in pain at rest after treatment was inversely correlated with pre-treatment masseters standardized surface electromyography symmetry (R-coefficient 0.3936; p < 0.05). Temporomandibular disorders patients showed a different muscular recruitment pattern compared to controls. The lesser the pre-treatment masseters symmetry, the greater the improvement of pain at rest after treatment.

Insertions of the striated muscles in the skin and mucosa: a histological study of fetuses and cadavers.

Striated muscle insertions into the skin and mucosa are present in the head, neck, and pelvic floor. We reexamined the histology of these tissues to elucidate their role in transmission of the force. We examined histological sections of 25 human fetuses (gestational ages of ~11-19 weeks and ~26-40 weeks) and 6 cadavers of elderly individuals. Facial muscle insertion or terminal almost always formed as an interdigitation with another muscle or as a circular arrangement in which muscle fiber insertions were sandwiched and mechanically supported by other muscle fibers (like an in-series muscle). Our examination of the face revealed some limited exceptions in which muscle fibers that approached the dermis were always in the nasalis and mentalis muscles, and often in the levator labii superioris alaeque nasi muscle. The buccinator muscle was consistently inserted into the basement membrane of the oral mucosa. Parts of the uvulae muscle in the soft palate and of the intrinsic vertical muscle of the tongue were likely to direct toward the mucosa. In contrast, the pelvic floor did not contain striated muscle fibers that were directed toward the skin or mucosa. Although 'cutaneous muscle' is a common term, the actual insertion of a muscle into the skin or mucosa seemed to be very rare. Instead, superficial muscle insertion often consisted of interdigitated muscle bundles that had different functional vectors. In this case, the terminal of one muscle bundle was sandwiched and fixed mechanically by other bundles.

Comparison of intraoperative outcomes in excision arthroplasty with or without partial tenotomy of deep gluteal muscle in dogs

Background: Excision arthroplasty is a commonly performed surgical technique for treating coxofemoral luxation in dogs. Favourable outcomes have been reported in dogs up to 15 kg. Aim: This study aimed to compare the intraoperative findings of two surgical approaches i.e., with or without partial deep gluteal muscle tenotomy in the excision arthroplasty in dogs. Methods: A total of 15 dogs having average body weight 15.6 kg (3.5-26) and 29.5 months (6-72) of age were brought to the Veterinary Surgery Clinics at University Veterinary Hospital, Samsun, Turkey with traumatic coxofemoral luxation or femur head/neck fracture. Craniolateral incision was used to approach the craniodorsal aspect of the hip joint in all cases. Myotomy of the superficial gluteal muscle and partial tenotomy of the deep gluteal was performed in one group. While blunt dissection approach was performed for elevation of gluteal muscles in another group. Results: Fifteen dogs (myotomy and tenotomy in 8 dogs and without tenotomy in 7 dogs) were diagnosed having lesions along with coxofemoral luxation in 9 cases, femoral neck fracture in 5 cases and caput femur fracture in 1 case. Partial tenotomy improved the exposure of joint capsule and femur neck. Discussion and Conclusion: The remnants of femoral neck after excision arthroplasty may contact the acetabulum and cause pain in the postoperative period. By applying the partial deep gluteal muscle tenotomy technique, surgeons can readily expose joint capsule, femoral head, femoral neck, and great and lesser trochanter.