The Effects of the StartReact on Reaction Time, Rate of Force Development, and Muscle Activity in Biceps Brachii.

The StartReact test, increasingly popular for assessing cortico-reticular functioning, is a valid method to influence the firing of reticulospinal tract neurons noninvasively. However, there remains limited evidence on how different stimuli employed in the StartReact test impact motor output in humans. The present study tested elbow flexor responses of 33 adults (aged 26-48 years) to visual stimuli only (LED light), audio-visual (80 dB) stimuli, and startle-inducing audio-visual (120 dB) stimuli sitting with the arm supinated in an electromechanical dynamometer. Surface electromyogram (EMG) recorded muscle activity from the right biceps brachii muscle. Participants were presented with 20 stimuli for each of the three conditions in pseudorandom order with interstimulus intervals of ~8 s. Reaction times were calculated from the stimulus trigger to the initial rise in the EMG signal above 7 × SD from baseline. Rate of torque development (RTD) and EMG signals were recorded throughout and analyzed over their initial 50 ms and 100 ms time-windows. Reaction times were reduced from visual (169 ± 23) to audio-visual (140 ± 23) and further reduced to startle-inducing audio-visual stimuli (108 ± 19, p < 0.001). While RTD and EMG were consistently greatest following startle-inducing stimuli (p < 0.001), they were also enhanced following all audio-visual stimuli over 100 ms (p < 0.05). It appears that startle-inducing audio-visual stimuli result in shorter reaction times, increased RTD, and enhanced muscle activity within the initial 50 ms, likely from subcortical upregulation. However, the 100 ms time-window suggests cortical upregulation following all audio-visual stimuli considering the longer transmission times.

The Crossing Motor Ulnar Nerve Branch at Elbow.

BACKGROUND AND OBJECTIVES: Cubital tunnel syndrome is the second most common nerve entrapment, and understanding the anatomy is crucial for the success of the nerve release. During ulnar nerve release for cubital tunnel syndrome, a motor branch is frequently encountered crossing anteriorly over the ulnar nerve from its medial/ulnar side proximally to the lateral/radial side distally. Little has been noted about this crossing branch in the literature. In this anatomic study, we sought to characterize this branch further and discuss its potential significance in cubital tunnel release. METHODS: We performed a cadaveric dissection of 48 elbow specimens as if performing a cubital tunnel release. We assessed for the presence of the crossing motor branch of the ulnar nerve and measured the distance from the medial epicondyle to the branch takeoff and to its target of innervation. RESULTS: Of our 48 specimens, 34 (71%) were noted to have a crossing motor branch at the area of compression by the deep flexor carpi ulnaris muscle fascia (common aponeurosis). On average, the distance from the medial epicondyle to the branch origin from the ulnar nerve was 18.2 mm and to the target muscle innervation was 28.4 mm. CONCLUSION: Identifying this branch is important for performing a cubital tunnel release, and awareness of this anatomy during ulnar nerve decompression procedures may help avoid injury to this motor branch.

A Comparison of Throwing Arm Kinetics and Ball Velocity in High School Pitchers With Overall Fast and Overall Slow Cumulative Joint and Segment Velocities.

BACKGROUND: Individual maximum joint and segment angular velocities have shown positive associations with throwing arm kinetics and ball velocity in baseball pitchers. PURPOSE: To observe how cumulative maximum joint and segment angular velocities, irrespective of sequence, affect ball velocity and throwing arm kinetics in high school pitchers. STUDY DESIGN: Descriptive laboratory study. METHODS: High school (n = 55) pitchers threw 8 to 12 fastball pitches while being evaluated with 3-dimensional motion capture (480 Hz). Maximum joint and segment angular velocities (lead knee extension, pelvis rotation, trunk rotation, shoulder internal rotation, and forearm pronation) were calculated for each pitcher. Pitchers were classified as overall fast, overall slow, or high velocity for each joint or segment velocity subcategory, or as population, with any pitcher eligible to be included in multiple subcategories. Kinematic and kinetic parameters were compared among the various subgroups using t tests with post hoc regressions and multivariable regression models created to predict throwing arm kinetics and ball velocity, respectively. RESULTS: The lead knee extension and pelvis rotation velocity subgroups achieved significantly higher normalized elbow varus torque (P = .016) and elbow flexion torque (P = .018) compared with population, with equivalent ball velocity (P = .118). For every 1-SD increase in maximum pelvis rotation velocity (87 deg/s), the normalized elbow distractive force increased by 4.7% body weight (BW) (B = 0.054; ß = 0.290; P = .013). The overall fast group was older (mean ± standard deviation, 16.9 ± 1.4 vs 15.4 ± 0.9 years; P = .007), had 8.9-mph faster ball velocity (32.7 ± 3.1 vs 28.7 ± 2.3 m/s; P = .002), and had significantly higher shoulder internal rotation torque (63.1 ± 17.4 vs 43.6 ± 12.0 Nm; P = .005), elbow varus torque (61.8 ± 16.4 vs 41.6 ± 11.4 Nm; P = .002), and elbow flexion torque (46.4 ± 12.0 vs 29.5 ± 6.8 Nm; P < .001) compared with the overall slow group. A multiregression model for ball velocity based on maximum joint and segment angular velocities and anthropometrics predicted 53.0% of variance. CONCLUSION: High school pitchers with higher maximum joint and segment velocities, irrespective of sequence, demonstrated older age and faster ball velocity at the cost of increased throwing shoulder and elbow kinetics. CLINICAL RELEVANCE: Pitchers and coaching staff should consider this trade-off between faster ball velocity and increasing throwing arm kinetics, an established risk factor for elbow injury.

A single-center retrospective comparison of muscle versus cutaneous free flaps for posterior elbow defect reconstruction.

INTRODUCTION: Comparative data on free flap outcomes for elbow defect reconstruction are still lacking. This study aimed to compare complication rates of free muscle flaps (MFs) versus cutaneous flaps (CFs) for posterior elbow reconstruction. METHODS: In a single-center retrospective analysis, patients who underwent posterior elbow reconstruction with free MFs and CFs from 2000 to 2021 were analyzed. Retrospective chart review included patient demographics, operative details, and post-operative complications. Outcomes of interest that were compared included microvascular complications, partial or total flap necroses, wound dehiscence, hematoma or flap infection, and donor-site complications. RESULTS: Sixty-six free flaps (CFs: n = 42; MFs: n = 24) were included, with a trend over time toward using CFs (64%). MFs were used for larger defects (CF: 175 ± 82 vs. MF: 212 ± 146 cm2; p = 0.13). Outcome analysis revealed an equal distribution of microvascular complications (10% vs. 13%; p = 0.7), partial flap necrosis (7% vs. 8%; p > 0.9), wound dehiscence (7% vs. 4%; p > 0.9), evacuation of hematoma (10% vs. 4%; p = 0.7), and infection (0% vs. 4%; p = 0.4). Total flap necrosis requiring additional flap surgery was necessary in one CF (2%) and in no MF (0%) (p > 0.9). CONCLUSION: Surgical outcomes, flap necrosis rates, and microsurgical complications did not differ between CFs and MFs. Both flap types are safe and effective options. The free anterolateral thigh and latissimus dorsi flaps represent indispensable workhorses for the reconstruction of extensive elbow defects.

The functional and clinical outcomes of primary and metastatic malignancies of the elbow.

OBJECTIVES: This study aims to investigate the etiological distribution of primary and metastatic malignancies around the elbow and the effect of surgical and adjuvant treatments on clinical outcome. PATIENTS AND METHODS: Between January 2006 and December 2020, medical records of a total of 33 patients with elbow neoplasm (15 males, 18 females; median age: 55 years; range, 39 to 71 years) who underwent surgical treatment and with or without clinical treatment were retrospectively analyzed. The outcomes and frequencies of the elbow metastatic and primary malignancies were evaluated. Data were collected from patients' medical and radiological documents, and a dedicated archive was created for this study. RESULTS: Most tumors occurred on the right side and were intra-articular or distal to the humerus. A total of 75.8% (25/33) of the patients had tumors of any diameter ≥5 cm. Most patients were treated with extensive resection. A total of 81.8% (27/33) of the patients had wide resected tumor margins, and 18.2% (6/33) had intralesional tumor margins. The median follow-up was 42 (range, 1 to 83) months. Synovial sarcoma and malignant peripheral nerve sheath tumors were the most common soft tissue sarcomas, and pulmonary adenoma and multiple myeloma were found in metastatic lesions. CONCLUSION: Elbow surgery is particularly challenging due to the interrelationship of major neurovascular structures. Synovial sarcoma and malignant peripheral nerve sheath tumors are the most common soft tissue sarcomas, and pulmonary adenoma and multiple myeloma are found in metastatic lesions. Limb-sparing surgery is the gold-standard method recently.

Sex-related differences in corticospinal excitability outcome measures of the biceps brachii during a submaximal elbow flexor contraction.

The purpose of this study was to investigate the effects of sex, muscle thickness, and subcutaneous fat thickness (SFT) on corticospinal excitability outcome measures of the biceps brachii. Eighteen participants (10 males and 8 females) completed this study. Ultrasound was used to assess biceps brachii muscle thickness and the overlying SFT. Transcranial magnetic stimulation (TMS) was used to determine corticospinal excitability by inducing motor-evoked potentials (MEPs) at eight different TMS intensities from 90% to 160% of active motor threshold (AMT) from the biceps brachii during an isometric contraction of the elbow flexors at 10% of maximum voluntary contraction (MVC). Biceps brachii maximal compound muscle action potential (Mmax) was also recorded prior to and after TMS. Males had higher (p < 0.001) biceps brachii muscle thickness and lower SFT, produced higher levels of MVC force and had, on average, higher (p < 0.001) MEP amplitudes at lower (p < 0.05) percentages of maximal stimulator output than females during the 10% elbow flexion MVC. Multiple linear regression modeling revealed that sex was not associated with any of the neurophysiological parameters examined, while SFT showed a positive association with the stimulation intensity required at AMT (p = 0.035) and a negative association with biceps brachii pre-stimulus electromyography (EMG) activity (p = 0.021). Additionally, there was a small positive association between muscle thickness and biceps brachii pre-stimulus EMG activity (p = 0.049). Overall, this study suggests that some measures of corticospinal excitability may be different between the sexes and influenced by SFT and muscle thickness.

Describing the Flick Movement Kinematic Biomechanically and Investigating the Effect of Thrower's Ten Exercises in Underwater Hockey Players.

CONTEXT: Analyzing flick movement kinematics biomechanically is important to prevent sport-related injuries in underwater hockey players since the aquatic-based flick movement is completely different from land-based flick movements. The study aimed to describe the flick movement kinematic biomechanically in underwater hockey players. Moreover, this study further aimed to investigate the effect of the Thrower's Ten exercises on flick movement kinematics in underwater hockey players. DESIGN: Descriptive laboratory study. METHODS: Seventeen underwater hockey players (age: 26.2 [4.3] y; sports age: 6.2 [4.5] y) were included. First, 2 underwater cameras using motion capture video analysis MATLAB were used to biomechanically analyze the angular changes on the shoulder, elbow, wrist, and body while players were performing the flick movements. Players were then recruited to the Thrower's Ten exercise program for 6 weeks. Flick movement kinematics and flick-throwing distance were recorded at baseline and 6 weeks. RESULTS: The flick movement kinematic patterns demonstrated increased shoulder flexion (from 102.5° to 144.9°), wrist extension (from 9.5° to 10.8°), and upper-extremity rotation (from 5.7° to 56.8°) while decreased elbow extension (from 107.7° to 159.2°) from the stick met the puck until the competition of the movement. The Thrower's Ten exercises improved the elbow extension (P = .04), wrist extension (P = .01), body rotation (P < .001), and flick-throwing distance (P < .001) from baseline to 6 weeks. CONCLUSION: This study describes the underwater flick kinematic technique biomechanically and interprets preliminary findings for the first time. Thus, 6 weeks of Thrower's Ten exercise program provides more body muscle movements than the smaller ones during the flick movements and higher flick-throwing distance in underwater hockey players.

[Anatomical cartography of the radial nerve at the elbow level for intraradial nerve transfers for finger extension reconstruction in spastic upper limb - A cadaveric study]. / Cartographie anatomique du nerf radial dans la région du coude pour son application aux transferts nerveux intraradiaux dans la chirurgie de la spasticité.

INTRODUCTION: Upper limb spasticity is a surgical challenge, both in diminishing agonists spasticity and reconstructing antagonist function. Brachioradialis (BR) is often involved in elbow flexors spasticity. Finger extension is often impaired in spastic patients. This study aims to demonstrate the feasibility of BR motor branch to posterior interosseous nerve (PIN) during BR selective neurectomies, and to describe fascicles topography inside the radial nerve to facilitate PIN dissection. MATERIAL AND METHOD: Ten upper limbs from 10 fresh frozen anatomical specimens were dissected. Motor branches to the BR, wrist extensors, supinator, PIN and radial sensory branch were identified. BR to PIN transfer was realized and its feasibility was studies (donor length, tensionless suture). RESULTS: BR to PIN transfer was achievable in 9 out of 10 cases. The position of the sensory branch of the radial nerve was inferior or medial in all cases. The position of the PIN was lateral in 90% of the cases. CONCLUSION: BR to PIN nerve transfer is achievable in most cases (90%). The lateral topography of the PIN and the inferomedial topography of the sensory branch in most cases allows for an easier intraoperative finding of the PIN when stimulation is not possible. LEVEL: IV, feasibility study.

Design and Development of a Powered Myoelectric Elbow Orthosis for Neuromuscular Injuries.

INTRODUCTION: Recovering from neuromuscular injuries or conditions can be a challenging journey that involves complex surgeries and extensive physical rehabilitation. During this process, individuals often rely on orthotic devices to support and enable movement of the affected limb. However, users have criticized current commercially available powered orthotic devices for their bulky and heavy design. To address these limitations, we developed a novel powered myoelectric elbow orthosis. MATERIALS AND METHODS: The orthosis incorporates 3 mechanisms: a solenoid brake, a Bowden cable-powered constant torque elbow mechanism, and an extension limiter. The device controller and battery are in a backpack to reduce the weight on the affected arm. We performed extensive calculations and testing to ensure that the orthosis could withstand at least 15 Nm of elbow torque. We developed a custom software effectively control the orthosis, enhancing its usability and functionality. A certified orthotist fitted a subject who had undergone a gracilis free functioning muscle transfer surgery with the device. We studied the subject under Mayo clinic IRB no. 20-006849 and obtained objective measurements to assess the orthosis's impact on upper extremity functionality during daily activities. RESULTS: The results are promising since the orthosis significantly improved elbow flexion range of motion by 40° and reduced compensatory movements at the shoulder (humerothoracic joint) by 50°. Additionally, the subject was able to perform tasks which were not possible before, such as carrying a basket with weights, highlighting the enhanced functionality provided by the orthosis. CONCLUSION: In brief, by addressing the limitations of existing devices, this novel powered myoelectric elbow orthosis offers individuals with neuromuscular injuries/conditions improved quality of life. Further research will expand the patient population and control mechanisms.

Acute Dosing Strategy with Vistula Tart Cherries for Recovery of Strenuous Exercise-A Feasibility Study.

Tart cherry (TC) consumption has become a popular nutritional strategy for recovery, particularly for the attenuation of markers associated with muscle damage. However, there are relatively few studies that have examined an acute dosing strategy. The aim of this pilot study was to explore the feasibility of using powdered Vistula TC for recovery following a bout of muscle-damaging exercise. Twenty-two recreationally active participants (mean ± SD age, stature, and mass were 23 ± 3 years old, 173 ± 10 cm, and 74 ± 17 kg, respectively) performed 40 (5 sets of 8 repetitions) maximal lengthening contractions of the elbow flexors. The participants were randomised to receive either a spray-dried TC extract or a calorie-matched placebo (12 TC, 10 placebo) for 4 days in total, starting on the day of exercise. Dependent measures of maximal voluntary contraction (MVC), muscle soreness (assessed via visual analogue scales; VAS), pain pressure threshold (PPT), range of motion (ROM), and upper arm limb girth were taken at baseline (pre), 24, 48, and 72 h post damaging exercise. There were significant changes over time among all the variables (MVC, VAS, PPT, ROM, and girth, p ≤ 0.014). There were no significant differences between the conditions for any of the variables (MVC, VAS, PPT, ROM, and girth, p > 0.3). The TC group did not recover at an accelerated rate compared to the placebo. This study provides initial insights into the use of powdered Vistula TC and its effect following strenuous (damaging) exercise bouts. Vistula TC did not improve recovery when taken acutely following a bout of damaging exercise to the elbow flexors.

Elbow Gesture Recognition with an Array of Inductive Sensors and Machine Learning.

This work presents a novel approach for elbow gesture recognition using an array of inductive sensors and a machine learning algorithm (MLA). This paper describes the design of the inductive sensor array integrated into a flexible and wearable sleeve. The sensor array consists of coils sewn onto the sleeve, which form an LC tank circuit along with the externally connected inductors and capacitors. Changes in the elbow position modulate the inductance of these coils, allowing the sensor array to capture a range of elbow movements. The signal processing and random forest MLA to recognize 10 different elbow gestures are described. Rigorous evaluation on 8 subjects and data augmentation, which leveraged the dataset to 1270 trials per gesture, enabled the system to achieve remarkable accuracy of 98.3% and 98.5% using 5-fold cross-validation and leave-one-subject-out cross-validation, respectively. The test performance was then assessed using data collected from five new subjects. The high classification accuracy of 94% demonstrates the generalizability of the designed system. The proposed solution addresses the limitations of existing elbow gesture recognition designs and offers a practical and effective approach for intuitive human-machine interaction.

MEFFNet: Forecasting Myoelectric Indices of Muscle Fatigue in Healthy and Post-Stroke During Voluntary and FES-Induced Dynamic Contractions.

Myoelectric indices forecasting is important for muscle fatigue monitoring in wearable technologies, adaptive control of assistive devices like exoskeletons and prostheses, functional electrical stimulation (FES)-based Neuroprostheses, and more. Non-stationary temporal development of these indices in dynamic contractions makes forecasting difficult. This study aims at incorporating transfer learning into a deep learning model, Myoelectric Fatigue Forecasting Network (MEFFNet), to forecast myoelectric indices of fatigue (both time and frequency domain) obtained during voluntary and FES-induced dynamic contractions in healthy and post-stroke subjects respectively. Different state-of-the-art deep learning models along with the novel MEFFNet architecture were tested on myoelectric indices of fatigue obtained during [Formula: see text] voluntary elbow flexion and extension with four different weights (1 kg, 2 kg, 3 kg, and 4 kg) in sixteen healthy subjects, and [Formula: see text] FES-induced elbow flexion in sixteen healthy and seventeen post-stroke subjects under three different stimulation patterns (customized rectangular, trapezoidal, and muscle synergy-based). A version of MEFFNet, named as pretrained MEFFNet, was trained on a dataset of sixty thousand synthetic time series to transfer its learning on real time series of myoelectric indices of fatigue. The pretrained MEFFNet could forecast up to 22.62 seconds, 60 timesteps, in future with a mean absolute percentage error of 15.99 ± 6.48% in voluntary and 11.93 ± 4.77% in FES-induced contractions, outperforming the MEFFNet and other models under consideration. The results suggest combining the proposed model with wearable technology, prosthetics, robotics, stimulation devices, etc. to improve performance. Transfer learning in time series forecasting has potential to improve wearable sensor predictions.

Risk and related factors of elbow musculoskeletal diseases: a nationwide cross-sectional survey in China.

OBJECTIVES: Although studies have shown that work-related musculoskeletal disorders (WMSDs) are common and continue to be a major source of disability and work time loss, there are few reports about elbow WMSDs. The aim of this study was to explore the prevalence and associated factors of elbow WMSDs. METHODS: The valid questionnaires of 57501 workers from 15 different industries nationwide were collected and the c2 test and logistic regression analysis were applied to reveal the prevalence and risk factors of elbow WMSDs. RESULTS: The findings indicated that the overall prevalence of elbow WMSDs among workers was 7.3%. However, the prevalence of elbow WMSDs in toy manufacturing was 21.3%, which was significantly higher than that in other industries (P < .05). Logistic regression analysis showed that age 40 and above, married, very poor health, left-handedness, lifting weights (more than 20 kg each time), work requiring upper limb or hand force, work in an uncomfortable position, repetitive operations within 1 minute, using vibrating tools, work involving cold, cool draughts, or temperature changes, work being completed in the same workshop, work being done outdoors, frequent dealings with customers, 2 shifts, often working overtime, staff shortage, and often working for colleagues were risk factors for elbow WMSDs. A higer education level, monthly income, and enough rest time were protective factors for elbow WMSDs. CONCLUSIONS: Toy manufacturing is a high-risk industry for elbow WMSDs. Promotion of education about ergonomics should be strengthened, and workers' ergonomics awareness should be improved to reduce the impact of WMSDs.

Minimum Intensity of Daily Six Eccentric Contractions to Increase Muscle Strength and Size.

Our previous study showed that daily six maximal eccentric contractions that were performed 5 days a week for 4 weeks increased maximal voluntary isometric (MVC-ISO), concentric (MVC-CON), and eccentric contraction (MVC-ECC) strength of the elbow flexors and muscle thickness of biceps brachii and brachialis (MT) by 8.3 ± 4.9%, 11.1 ± 7.4%, 13.5 ± 11.5%, and 10.6 ± 5.1%, respectively. In the present study, we tested the hypothesis that the muscle strength and MT would still increase when the training intensity was reduced to 2/3 or 1/3 of the peak MVC-ECC torque. Thirty-six healthy young (19-24 years) adults who had not performed resistance training were placed to three groups (n = 12/group): 2/3MVC or 1/3MVC that performed six eccentric contractions with 2/3 or 1/3 MVC-ECC load using a dumbbell 5 days a week for 4 weeks or control group that did not perform any training. Changes in the MVC-ISO, MVC-CON, MVC-ECC torque, and MT before and after the 4-week period were compared among the groups and with the group of the previous study in which six maximal eccentric contractions were performed 5 days a week for 4 weeks (MVC group; n = 12). The control and 1/3MVC groups showed no significant changes in any measures. Significant (p < 0.05) increases in MVC-ISO (10.3 ± 11.4%), MVC-CON (10.9 ± 9.5%), and MVC-ECC (9.3 ± 8.8%) torque and MT (10.1 ± 9.2%) were observed for the 2/3MVC group. These changes were not significantly different from those of the MVC group. These results suggest that the 2/3-intensity eccentric contractions with a dumbbell are as effective as maximal-intensity isokinetic eccentric contractions to induce muscle adaptations.

Double entrapment neuropathy of the ulnar nerve at the elbow and the wrist : double crush syndrome?

BACKGROUND: Double crush syndrome refers to a nerve in the proximal region being compressed, affecting its proximal segment. Instances of this syndrome involving ulnar and cubital canals during ulnar neuropathy are rare. Diagnosis solely through clinical examination is challenging. Although electromyography (EMG) and nerve conduction studies (NCS) can confirm neuropathy, they do not incorporate inching tests at the wrist, hindering diagnosis confirmation. We recently encountered eight cases of suspected double compression of ulnar nerve, reporting these cases along with a literature review. METHODS: The study included 5 males and 2 females, averaging 45.6 years old. Among them, 4 had trauma history, and preoperative McGowan stages varied. Ulnar neuropathy was confirmed in 7 cases at both cubital and ulnar canal locations. Surgery was performed for 4 cases, while conservative treatment continued for 3 cases. RESULTS: In 4 cases with wrist involvement, 2 showed ulnar nerve compression by a fibrous band, and 1 had nodular hyperplasia. Another case displayed ulnar nerve swelling with muscle covering. Among the 4 surgery cases, 2 improved from preoperative McGowan stage IIB to postoperative stage 0, with significant improvement in subjective satisfaction. The remaining 2 cases improved from stage IIB to IIA, respectively, with moderate improvement in subjective satisfaction. In the 3 cases receiving conservative treatment, satisfaction was significant in 1 case and moderate in 2 cases. Overall, there was improvement in hand function across all 7 cases. CONCLUSION: Typical outpatient examinations make it difficult to clearly differentiate the two sites, and EMG tests may not confirm diagnosis. Therefore, if a surgeon lacks suspicion of this condition, diagnosis becomes even more challenging. In cases with less than expected postoperative improvement in clinical symptoms of cubital tunnel syndrome, consideration of double crush syndrome is warranted. Additional tests and detailed EMG tests, including inching tests at the wrist, may be necessary. We aim to raise awareness double crush syndrome with ulnar nerve, reporting a total of 7 cases to support this concept.

Changes in brain functional connectivity and muscle strength independent of elbow flexor atrophy following upper limb immobilization in young females.

Muscle disuse induces a decline in muscle strength that exceeds the rate and magnitude of muscle atrophy, suggesting that factors beyond the muscle contribute to strength loss. The purpose of this study was to characterize changes in the brain and neuromuscular system in addition to muscle size following upper limb immobilization in young females. Using a within-participant, unilateral design, 12 females (age: 20.6 ± 2.1 years) underwent 14 days of upper arm immobilization using an elbow brace and sling. Bilateral measures of muscle strength (isometric and isokinetic dynamometry), muscle size (magnetic resonance imaging), voluntary muscle activation capacity, corticospinal excitability, cortical thickness and resting-state functional connectivity were collected before and after immobilization. Immobilization induced a significant decline in isometric elbow flexion (-21.3 ± 19.2%, interaction: P = 0.0440) and extension (-19.9 ± 15.7%, interaction: P = 0.0317) strength in the immobilized arm only. There was no significant effect of immobilization on elbow flexor cross-sectional area (CSA) (-1.2 ± 2.4%, interaction: P = 0.466), whereas elbow extensor CSA decreased (-2.9 ± 2.9%, interaction: P = 0.0177) in the immobilized arm. Immobilization did not differentially alter voluntary activation capacity, corticospinal excitability, or cortical thickness (P > 0.05); however, there were significant changes in the functional connectivity of brain regions related to movement planning and error detection (P < 0.05). This study reveals that elbow flexor strength loss can occur in the absence of significant elbow flexor muscle atrophy, and that the brain represents a site of functional adaptation in response to upper limb immobilization in young females.

Experience of living with chronic pain in conjunction with surgery for ulnar nerve entrapment at the elbow-A qualitative study.

PURPOSE: Pain in conjunction with surgery for ulnar nerve entrapment at the elbow is seldom highlighted in the literature. This study aimed to explore patients' experiences of living with chronic pain (≥3 months duration) in conjunction with surgery for ulnar nerve entrapment at the elbow, the consequences and the coping strategies applied. MATERIAL AND METHODS: In-depth interviews were conducted with 10 participants aged 18-60 years. The narratives were analyzed using an inductive approach and content-analysis. RESULTS: The analysis revealed seven main categories: "Physical symptoms/impairments" and "Mood and emotions"comprise symptoms caused by ulnar nerve entrapment at the elbow and chronic pain; "Consequences in daily life" includes challenges and obstacles in every-day life, impact on leisure activities and social life; "Struggling with self-image" embraces experiences closely related to identity; "Coping strategies" covers adaptive resources; "Experience of relief "describes perceived improvements; "Key message for future care" comprises important aspects for healthcare providers to consider. CONCLUSIONS: The results clarify the need for healthcare personnel to adopt a biopsychosocial approach when treating patients with ulnar nerve entrapment at the elbow. Emotional symptoms and sleep disturbances should be identified and treated properly since they contribute to the heavy burden experienced by the individual.

Diagnostic efficiency of conventional ultrasound, shear wave elastography, and superb microvascular imaging in evaluating ulnar neuropathy at the elbow.

INTRODUCTION/AIMS: The current diagnosis of ulnar neuropathy at the elbow (UNE) relies mainly on the clinical presentation and nerve electrodiagnostic (EDX) testing, which can be uncomfortable and yield false negatives. The aim of this study was to investigate the diagnostic value of conventional ultrasound, shear wave elastography (SWE), and superb microvascular imaging (SMI) in diagnosing UNE. METHODS: We enrolled 40 patients (48 elbows) with UNE and 48 healthy volunteers (48 elbows). The patients were categorized as having mild, moderate or severe UNE based on the findings of EDX testing. The cross-sectional area (CSA) was measured using conventional ultrasound. Ulnar nerve (UN) shear wave velocity (SWV) and SMI were performed in a longitudinal plane. RESULTS: Based on the EDX findings, UNE severity was graded as mild in 4, moderate in 10, and severe in 34. The patient group showed increased ulnar nerve CSA and stiffness at the site of maximal enlargement (CSA mean at the site of max enlargement [CSAmax] and SWV mean at the site of max enlargement [SWVmax]), ulnar nerve CSA ratio, and stiffness ratio (elbow-to-upper arm), compared with the control group (p < .001). Furthermore, the severe UNE group showed higher ulnar nerve CSAmax and SWVmax compared with the mild and moderate UNE groups (p < .001). The cutoff values for diagnosis of UNE were 9.5 mm2 for CSAmax, 3.06 m/s for SWVmax, 2.00 for CSA ratio, 1.36 for stiffness ratio, and grade 1 for SMI. DISCUSSION: Our findings suggest that SWE and SMI are valuable diagnostic tools for the diagnosis and assessment of severity of UNE.

Compressive Structures of the Median Nerve at the Elbow / Estructuras Compresivas del Nervio Mediano en el Codo

SUMMARY: The objective of this study was to analyze the potential for compression of the median nerve (MN) caused by the bicipital aponeurosis (BA), the humeral and ulnar heads of the pronator teres muscle (PTM) and the arcade of the flexor digitorum superficialis muscle (FDS) in recently deceased cadavers. In this analysis 20 forearms of 10 recently deceased adult male cadavers were dissected. Dissections were performed in the institution's autopsy room or anatomy laboratory. The short and long heads of the biceps brachii muscle, as well as the BA were identified in all upper upper limbs. The BA received contribution from the short and long heads of the biceps brachii muscle. In 12 upper limbs the BA was wide and thickened and in 8 it was supported by the MN. In 5 upper limbs, the BA was wide but not very thick, and in 3 it was narrow and not very thick. We identified the existence of the FDS muscle arcade in all dissected upper limbs. A fibrous arcade was identified in 4 forearms, a muscular arcade in 14 and a transparent arcade in 2 upper limbs. In all of them, we recorded that the arcade was in contact with the MN. We recorded the humeral and ulnar heads of the PTM in all dissected upper limbs, with the presence of fibrous beams between them along their entire length. The MN was positioned between the humeral and ulnar heads of the PTM in all upper limbs. In eight upper limbs (40 %), we identified that the BA had thickness and contact with the MN with the potential to cause its compression. Compression between the humeral and ulnar heads of the PTM by the fibrous connections has the potential to cause nerve compression in all upper limbs (100 %). We did not identify that the anatomical structure of the FDS arcade had the potential to cause compression in the MN.

El objetivo de este estudio fue analizar la potencial compresión del nervio mediano (NM) causado por la aponeurosis bicipital (AB), las cabezas humeral y cubital del músculo pronador redondo (MPR) y la arcada del músculo flexor superficial de los dedos (MFS). En este análisis se diseccionaron 20 antebrazos de 10 cadáveres masculinos de individuos adultos fallecidos recientemente. Las disecciones se realizaron en la sala de autopsias o en el laboratorio de anatomía de la Institución. En todos los miembros superiores se identificaron las cabezas corta y larga del músculo bíceps braquial, así como la AB. La AB recibió contribución de las cabezas corta y larga del músculo bíceps braquial. En 12 miembros superiores la AB era ancha y engrosada y en 8 estaba sostenida por el NM. En 5 miembros superiores la AB era ancha pero poco gruesa, y en 3 era estrecha y de menor grosor. Identificamos la existencia de la arcada muscular MFS en todos los miembros superiores disecados. Se identificó una arcada fibrosa en 4 antebrazos, una arcada muscular en 14 y una arcada delgada y transparente en 2 miembros superiores. En todos ellos registramos que la arcada estaba en contacto con el NM. Registramos las cabezas humeral y cubital del MPR en todos los miembros superiores disecados, con presencia de haces fibrosos entre ellas en toda su longitud. El NM estaba situado entre las cabezas humeral y cubital del MPR en todos los miembros superiores. En ocho miembros superiores (40 %), identificamos que la AB era gruesa y tenía contacto con el NM con potencial para causar su compresión. La compresión entre las cabezas humeral y ulnar del MPR, por las conexiones fibrosas, tiene el potencial de causar compresión nerviosa en todos los miembros superiores (100 %). No identificamos que la estructura anatómica de la arcada MFS tuviera el potencial de causar compresión del NM.

Evidence of the existence of multiple modules for the stroke-caused flexion synergy from Fugl-Meyer assessment scores.

Stroke-caused synergies may result from the preferential use of the reticulospinal tract (RST) due to damage to the corticospinal tract. The RST branches multiple motoneuron pools across the arm together resulting in gross motor control or abnormal synergies, and accordingly, the controllability of individual muscles decreases. However, it is not clear whether muscles involuntarily activated by abnormal synergy vary depending on the muscles voluntarily activated when motor commands descend through the RST. Studies showed that abnormal synergies may originate from the merging and reweighting of synergies in individuals without neurological deficits. This leads to a hypothesis that those abnormal synergies are still selectively excited depending on the context. In this study, we test this hypothesis, leveraging the Fugl-Meyer assessment that could characterize the neuroanatomical architecture in individuals with a wide range of impairments. We examine the ability to perform an out-of-synergy movement with the flexion synergy caused by either shoulder or elbow loading. The results reveal that about 14% [8/57, 95% confidence interval (5.0%, 23.1%)] of the participants with severe impairment (total Fugl-Meyer score <29) in the chronic phase (6 months after stroke) are able to keep the elbow extended during shoulder loading and keep the shoulder at neutral during elbow loading. Those participants underwent a different course of neural reorganization, which enhanced abnormal synergies in comparison with individuals with mild impairment (P < 0.05). These results provide evidence that separate routes and synergy modules to motoneuron pools across the arm might exist even if the motor command is mediated possibly via the RST.NEW & NOTEWORTHY We demonstrate that abnormal synergies are still selectively excited depending on the context.