Scapulothoracic Muscles Research Articles

Influence of phase and dominance on ground reaction forces and upper extremity muscle activity during the modified-Closed Kinetic Chain Upper Extremity Stability Test

BackgroundThe Closed Kinetic Chain Upper Extremity Stability Test (CKCUEST) is a physical performance test designed to assess the upper extremity (UE) stability. However, only one outcome measure is provided for both UEs, limiting its application if the UEs are not similarly involved. Moreover, the changes in loads sustained by the support UE throughout the movement may influence the support UE stability. Additional knowledge on the underpinning biomechanical mechanics of the performance is therefore needed to better understand how to use the measure of the CKCUEST to design the athlete’s physical ability development or recovery. This study aimed to investigate the influence of phase and dominance on kinetic and support UE muscular demand during a modified-CKCUEST touch.MethodsTwenty-five male multisport athletes (age: 26.0 ± 11.3 years; mass: 77.8 ± 23.3 kg; height: 179.0 ± 6.5 cm) performed the modified-CKCUEST, i.e. hands at half span apart. The ground reaction forces (GRF) and activity of eight perihumeral and scapulothoracic muscles of support UE were recorded and analyzed according to the UE dominance and phase (takeoff vs. landing). Statistical non-Parametric Mapping analyses were used to assess the effects of dominance and phase on the support UE GRF and the effects of dominance, phase, and muscle on the support UE muscle activity.ResultsThe scapulothoracic and perihumeral muscles of the support UE were activated at low-to-very-high levels during the modified-CKCUEST touch. Variations in muscular activity over a touch were required to sustain variations in loads in medial, vertical, and posterior directions. Lower loads were observed during the takeoff phase than those during the landing phase (p < 0.05). Despite similar muscular activities in both UEs, the dominant UE sustained higher medial loads than the non-dominant UE (p < 0.05), while opposite results were observed for posterior loads (p < 0.05).ConclusionsThe modified-CKCUEST involves similar muscle activity of the support UE in response to varying loads sustained in different directions according to dominance. The quantitative assessment provided by the modified-CKCUEST score may be complemented by a qualitative observation of body displacements, allowing coaches and clinicians to identify limitations in the stability of the UEs.

Electromyographic comparison of exercises for scapulothoracic muscle activation in men with upper crossed syndrome: A cross-sectional study

ObjectiveThis study aimed to determine the optimal exercise for improving Upper Crossed Syndrome (UCS) using electromyographic (EMG) activity of upper trapezius (UT), middle trapezius (MT), lower trapezius (LT), and serratus anterior (SA) during ten exercises. MethodA cross-sectional study involved 30 male students (mean age: 25.3 ± 2.5 years; height: 176.8 ± 7.2 cm; weight: 77.7 ± 2.5 kg; BMI: 23.8 ± 0.72 kg/m2) with UCS. Participants were selected based on postural assessments (forward head posture ≥44°, rounded shoulder ≥49°, thoracic kyphosis ≥42°). EMG was used to measure activation levels of UT, MT, LT, and SA, and the UT activation ratio relative to MT, LT, and SA during ten exercises. One-way ANOVA was applied for data analysis. ResultsSide-lying external rotation, standing diagonal flexion with Thera-band, and lying prone “V” demonstrated the least UT activity, with the highest MT and LT activation. The standing diagonal flexion with Thera-band elicited the highest SA activity. UT/MT, UT/LT, and UT/SA ratios were less than one in multiple exercises. Significant differences in muscle activation levels and ratios were observed across all exercises (P ≤ 0.05). ConclusionThe findings suggest significant clinical implications for UCS rehabilitation. The identified exercises effectively engage MT and LT while minimizing UT activation, addressing muscular imbalances. Favorable UT/MT, UT/LT, and UT/SA ratios further support these exercises in correcting UCS. These exercises may help counteract the underlying muscular imbalance in UCS by promoting a more balanced activity ratio among the shoulder girdle muscles, potentially improving posture and reducing UCS symptoms.

Voluntary Contraction of the Abdominal Muscles During Shoulder Exercises Increases Scapular Muscle Activation: A Critically Appraised Topic.

The fascial relationship between scapular muscles and abdominal muscles has been documented from previous studies. However, it is not yet clear whether voluntary abdominal contraction has a beneficial effect on scapular muscle activity during shoulder exercises. Do scapulothoracic muscle activation levels increase if shoulder exercises are performed with voluntary abdominal activation? Summary of Key Finding: After the literature review, 4 cross-sectional studies met the inclusion criteria and were included in this critically appraised topic. There is moderate evidence to support dynamic shoulder exercises with voluntary abdominal contraction can increase trapezius and serratus anterior muscle activation level in asymptomatic shoulders. Strength and Recommendation: Findings from 4 cross-sectional trials indicate that there is moderate evidence supporting that dynamic shoulder exercises performed with voluntary abdominal contraction can increase scapular muscle activity.

The latissimus dorsi creates a dynamic track for the inferior angle of the scapula during arm abduction in humans

BackgroundThe importance of several scapulothoracic muscles, including trapezius and serratus anterior, in maintaining physiological scapula kinematics has been highlighted in the past. However, the relationship between the scapula and the latissimus dorsi muscle remains unclear. Our clinical surgical observation is that the latissimus dorsi does not directly attach but rather runs superficial to the inferior angle of the scapula. Based on this observation, we hypothesise that the latissimus dorsi creates a dynamic track on which the scapula glides under the muscle belly during elevation of the arm, creating the latissimus-scapula overlap (LSO).MethodsAll consecutive patients who had a whole-body computed tomography scan (CT) in case of polytrauma evaluation between 2018 and 2021, with complete depiction of the scapula and latissimus dorsi muscle, were analysed. 150 shoulders in 90 patients with arms up were matched according to their age (within five years), gender, and affected side with 150 shoulders in 88 patients with arms down. Patients with pathologies of the upper extremities or thorax that potentially could alter LSO measurements were excluded. LSO was calculated as a ratio of the measured area of the latissimus dorsi projection on the scapula and the total scapula area.ResultsThe mean age of the 178 patients (48 females; 13 males) was 60 years. The arms-up group showed a significantly higher LSO than the arms-down group (19.9 ± 6.3% vs. 2.7 ± 2.2%; p < 0.0001). In the arms-up group, approximately one fifth of the scapula was overlapped inferiorly by the muscle belly of the latissimus dorsi, contrary to the almost non-existing LSO in the arms-down group.ConclusionWith arms up, humans show a significantly higher LSO in comparison to arms down indicating that the latissimus dorsi indeed creates a dynamic track on which the scapula is forced to travel during abduction of the arm. This finding of increased LSO during the elevation of the arm warrants further consideration of the role of the latissimus dorsi in scapula kinematics and potentially scapular dyskinesis.Level of evidenceLevel two diagnostic study.

Comparison of the activation and mechanical properties of scapulothoracic muscles in young tennis players with and without scapular dyskinesis: an observational comparative study

In tennis athletes with scapular dyskinesis, the activation of the scapulothoracic muscles during serve is not known. Also, the mechanical properties (tone, elasticity, and stiffness) of the scapulothoracic muscles of the tennis athletes with scapular dyskinesis are likely to change. The study aimed to evaluate the activation of the scapulothoracic muscles while performing tennis serve and to determine the changes in the mechanical properties of the same muscles in young tennis athletes with scapular dyskinesis. Seventeen tennis athletes with scapular dyskinesis aged between 11 and 18 years (the scapular dyskinesis group) and age- and gender-matched 17 asymptomatic tennis athletes (the control group) were included in the study. Activation of scapulothoracic muscles (descending-transverse-ascending trapezius and serratus anterior) in the 3 phases (preparation, acceleration, and follow-through) of the serve was evaluated using surface electromyography, and the mechanical properties of the same muscles were measured at rest by myotonometry. Ascending trapezius activation in the follow-through phase was lower in the scapular dyskinesis group compared with the control group (mean difference 95% confidence interval: -22.8 [-41.2 to -4.5]) (P=.017). The tone and stiffness of the transverse trapezius (P=.043 and P=.017, respectively) were higher, whereas the same parameters of the ascending trapezius were lower (P=.008 and P=.010, respectively) in the scapular dyskinesis group compared with the control group. Activation of the ascending trapezius and the tone and stiffness of the transverse-ascending trapezius were altered in tennis athletes with scapular dyskinesis. Implementations to improve these changes can be included in the rehabilitation or training programs of young tennis athletes with scapular dyskinesis.

Comparison of isometric strength in rotator cuff and scapulothoracic muscles between elite volleyball athletes versus non-athletes.

Volleyball is an exceptionally popular global sport that involves repetitive, rapid, powerful and wide overhead movements, which can seriously alter normal shoulder kinematics. A recognized hallmark of shoulder muscle balance is the ratio of shoulder external (ER) and internal (IR) rotators. By extension, objective measurement of shoulder muscles' strength could help identify at risk athletes and preempt those injuries by engaging in prescriptive strength training programs. This cross-sectional study measured the isometric strengths of 1) shoulder internal and external rotator muscles, as well as the 2) supraspinatus, 3) rhomboid, and 4) middle and inferior trapezius muscles, in addition to calculation of ER:IR ratios, in professional volleyball players as well as in non-athletes. Measurements were made for dominant- and non-dominant upper limbs, in different position of the body (supine and orthostatic) and in different position of upper limb (adducted and abducted position). Our subject population included 11 male professional volleyball players as well as 14 healthy male orthopedic interns from Orthopedics and Trauma school of University of Milano Bicocca. Strengths were assessed by a handheld dynamometer. Each subject's isometric strength was assessed in triplicate in each limb position through a "make test" procedure; the greatest of each triplicate value was the accepted measure of isometric strength. We observed a gradient in muscle strength in the scapulothoracic complex in both groups; the rhomboid, middle trapezius, and lower trapezius ranked from greatest to least strength, respectively. The data suggest also that intrarotators are stronger in rotation adducted position than in rotation abducted position; however, extrarotators seem to be weaker in rotation adducted position than in rotation abducted position. There is also some indication that force development is enhanced in the supine position compared with the orthostatic position. Our findings indicate a scapulothoracic strength gradient with a rank order of strength of the rhomboid>middle trapezius>lower trapezius. The data further suggest that volleyball players have stronger intrarotation in rotation adducted position than in the rotation abducted position, while extra rotation shows the opposite trend. Finally, our data suggest that force development is greater in the supine position compared to the orthostatic position.

The effect of pathological shoulder rhythm on muscle and joint forces after reverse shoulder arthroplasty, a numerical analysis

BackgroundCompromised abduction ability after reverse shoulder arthroplasty is primarily linked to limited glenohumeral range of motion while scapulothoracic mobility can typically be maintained. Glenohumeral joint forces strongly depend on the resulting scapulohumeral rhythm, however, an association between the acting muscle and joint forces and the subject-specific scapulohumeral rhythm after reverse shoulder arthroplasty has not been established. MethodsEleven reverse shoulder arthroplasty patients were divided into groups of poor and excellent abduction ability. Subject-specific models were developed and scaled for each patient using existing motion capture data in AnyBody™. Shoulder muscle and joint forces were obtained using inverse dynamics calculations during shoulder abduction to 100° in the scapula plane. The scapulohumeral rhythm, the resting abduction angle and internal body forces between the outcome groups were compared using a Mann Whitney U test. FindingsThe mean glenohumeral and scapulothoracic contribution to overall shoulder abduction for the excellent group was on average 9.7% higher and 21.4% lower, respectively, compared to the mean of the poor group. For shoulder abduction angles between 30° and 60°, the excellent group demonstrated on average 25% higher muscle forces in the anterior deltoid which was significantly higher compared to the poor outcome patients. Scapulothoracic muscle activity did not differ significantly between the two functional groups. InterpretationAccordingly, rehabilitation strategies focusing on strengthening the anterior part of the deltoid in particular may improve clinical outcomes.

Assessment of pain, scapulothoracic muscle strength, endurance and scapular dyskinesis in individuals with and without nonspecific chronic neck pain: A cross-sectional study

IntroductionThis study is aimed to evaluate pain, muscle strength, scapular muscular endurance and scapular kinesis in individuals with Nonspecific Chronic Neck Pain and to compare them with asymptomatic individuals. In addition, to investigate the effect of mechanical changes in the scapular region on neck pain. Method40 individuals who applied to Kırıkkale University Faculty of Medicine Hospital Physical Therapy and Rehabilitation Center and diagnosed with NSCNP and 40 asymptomatic individuals for the control group were included the study. Pain was evaluated with Visual Analogue Scale, pain threshold and pain tolerance with algometer, cervical deep flexor group muscle strength with Stabilizer Pressure Biofeedback device, and neck and scapulothoracic muscle strength with Hand Held Dynamometer. Scapular Dyskinesia Test, Scapular Depression Test and Lateral Scapular Slide Test were used to evaluate scapular kinesis. A timer was used to evaluate scapular muscular endurance. ResultPain threshold and pain tolerance values of the NSCNP group were lower (p < 0.05). Muscle strength around neck and scapulothoracic region of the NSCNP group were lower than the asymptomatic individuals (p < 0.05). NSCNP group had more scapular dyskinesia (p < 0.05). Scapular muscular endurance values of the NSCNP group were lower (p < 0.05). ConclusionAs a result, pain threshold and pain tolerance decreased, muscle strength of the neck region and the scapular region decreased, scapular endurance values decreased and the incidence of scapular dyskinesia increased in the individuals with NSCNP compared to the asymptomatic individuals. It is thought that our study will provide a different perspective in the evaluation of neck pain and including the scapular region to the evaluations.

Exercises With Optimal Scapulothoracic Muscle Activation for Individuals With Paraplegia.

Individuals with paraplegia and coexisting trunk and postural control deficits rely on their upper extremities for function, which increases the risk of shoulder pain. A multifactorial etiology of shoulder pain includes "impingement" of the supraspinatus, infraspinatus, long head of the biceps tendons, and/or subacromial bursa resulting from anatomic abnormalities, intratendinous degeneration, and altered scapulothoracic kinematics and muscle activation. Targeting serratus anterior (SA) and lower trapezius (LT) activation during exercise, as part of a comprehensive plan, minimizes impingement risk by maintaining optimal shoulder alignment and kinematics during functional activities. To prevent excessive scapular upward translation, minimizing upper trapezius (UT) to SA and LT activation is also important. To determine which exercises (1) maximally activate SA and minimize UT:SA ratio and (2) maximally activate LT and minimize UT:LT ratio. Kinematic and muscle activation data were captured from 10 individuals with paraplegia during four exercises: "T," scaption (sitting), dynamic hug, and SA punch (supine). Means and ratios were normalized by percent maximum voluntary isometric contraction (MVIC) for each muscle. One-way repeated measures analysis of variance determined significant differences in muscle activation between exercises. Exercises were rank ordered: (1) maximum SA activation: SA punch, scaption, dynamic hug, "T"; (2) maximum LT activation: "T," scaption, dynamic hug, SA punch; 3) minimum UT:SA ratio: SA punch, dynamic hug, scaption, "T"; and (4) minimum UT:LT ratio: SA punch, dynamic hug, "T," scaption. Exercise elicited statistically significant changes in percent MVIC and ratios. Post hoc analyses revealed multiple significant differences between exercises (p < .05). SA punch produced the greatest SA activation and lowest ratios. Dynamic hug also produced optimal ratios, suggesting supine exercises minimize UT activation more effectively. To isolate SA activation, individuals with impaired trunk control may want to initiate strengthening exercises in supine. Participants maximally activated the LT, but they were not able to minimize UT while upright.

Effects of scapulothoracic stabilization exercises on scapular function, posture, and balance in lymphedema after mastectomy: a randomized controlled trial

ABSTRACT This study aimed to investigate the effects of scapulothoracic stabilization exercises (SSE) on scapular function, posture, and balance in women with lymphedema after mastectomy. The patients were randomly divided into two groups as complex decongestive physiotherapy (CDP) (n: 12; age: 55.25 ± 8.17 years) and CDP+SSE (n: 13; age: 54.38 ± 9.08 years). While only CDP was applied in the CDP group, CDP and SSE were applied in the CDP+SSE group. Scapulothoracic muscle strength with dynamometer, scapular endurance with Scapular Isometric Compression Test, scapular dyskinesia with Lateral Scapular Slide Test, thoracic posture with inclinometer, general posture with New York Posture Scale, and balance with Mini-BESTest were evaluated before the 3-week treatment phase (TP), after the TP, and after the fifth week of the maintenance phase (MP). Improvements in the lower trapezius muscle strength were found in both groups after the TP (p < .05). In addition, the middle trapezius muscle strength and general posture improved more in the CDP+SSE group than in the CDP group after the TP (p < .05). In the MP, scapulothoracic muscle strength, scapular endurance, and general posture improved more in CDP+SSE group compared to the CDP group (p < .05). In upper extremity lymphedema patients, incorporating additional SSE in CDP may contribute to the improvement of posture and scapular functions.

Comparison of the scapulothoracic muscles activity in individuals with and without shoulder pain and scapular dyskinesis: A preliminary time-series study

Comparison of the scapulothoracic muscles activity in individuals with and without shoulder pain and scapular dyskinesis: A preliminary time-series study

Scapular movement training is not superior to standardized exercises in the treatment of individuals with chronic shoulder pain and scapular dyskinesis: randomized controlled trial

Purpose To investigate whether scapular movement training (SMT) is superior to standardized exercises in improving scapular biomechanics, behavioral, and clinical aspects of individuals with shoulder pain. Methods and methods A total of 64 individuals with chronic shoulder pain were randomly assigned to receive 16 sessions of SMT or SE over 8 weeks. Outcome measures included three-dimensional scapular kinematics, muscle activity of scapulothoracic muscles, pain, disability, fear-avoidance, kinesiophobia, and self-perceived changes. Kinematics and muscle activity were assessed at baseline and after treatment, and self-reported measurements at baseline, 4, 8, and 12 weeks. Results SMT significantly (p < 0.05) decreased scapular internal rotation during arm elevation and lowering at sagittal and scapular planes (mean difference [MD]: ranged from 2.8 to 4.1°), and at lower angles of arm elevation and lowering at the frontal plane (MD: 3.4° and 2.4°, respectively), increased upper trapezius (UT) activity (MD: 10.3%) and decreased middle trapezius (MT) (MD: 60.4%) and serratus anterior (MD: 9.9%) activity during arm lowering compared to SE. Both groups significantly improved pain, disability, fear-avoidance, kinesiophobia, and self-perceived changes over 4 weeks, which was sustained over the remaining 8 weeks. Conclusions SMT is not superior to standardized exercises in improving scapular biomechanics, behavioral, and clinical aspects of individuals with shoulder pain. Clinical trial registration number NCT03528499 Implications for rehabilitation Scapular movement training (SMT) showed small and likely not clinically relevant changes in scapular kinematics and muscle activity compared to standardized exercises. SMT and standardized exercises presented similar improvements in pain, disability, fear-avoidance beliefs, kinesiophobia, and self-perceived change in health condition immediately following 4-weeks of treatment, which was sustained over the following 8 weeks. The changes in patient-reported outcome measures are unlikely to be associated with changes in scapular kinematics and electromyographic activity. Clinicians should consider other factors than scapular movement during the treatment of patients with shoulder pain.

Scapulothoracic muscle activity during kinetic chain variations of a prone elevation exercise

BackgroundScapular rehabilitation exercises should target appropriate muscles. Recently, adding external rotation resistance to scapular exercises has gained interest. Moreover, clinical experts advise kinetic chain integration into shoulder rehabilitation exercises. ObjectiveTo investigate scapular muscle activity during kinetic chain variations of a prone elevation exercise. MethodsActivity of the upper (UT), middle (MT), and lower (LT) trapezius and serratus anterior (SA) muscles was determined with surface electromyography (EMG) in 31 asymptomatic participants during six prone elevation exercise variations. Variation was created by adding external rotation resistance, adding trunk extension, or changing exercise position (prone on a Swiss ball with knees or feet supported, or prone on a physiotable). All data were normalized as a percentage of maximal voluntary isometric contraction (% MVIC). For each muscle, a Friedman's ANOVA was conducted to analyse statistical differences in EMG signal intensity between exercises. ResultsThe LT was moderately (42 - 48% MVIC) and MT highly (63 - 66% MVIC) activated during all exercise variations. No significant differences between exercises for these muscles could be detected. Adding external rotation to a prone elevation exercise decreased UT activity while adding trunk extension increased UT activity. Altering exercise position had no influence on scapular muscle activity except increased UT activity when lying prone on a physiotable with trunk extension. ConclusionProne elevation exercises are appropriate for facilitating LT and MT activity. Adding external rotation inhibits UT activity while UT facilitation could be achieved when adding trunk extension.

Effect of Lower Trapezius, Middle Trapezius and Serratus Anterior Muscles Strengthening on Pain, Muscle Strength and Functional Status in individuals with Non-Specific Chronic Neck Pain

Background: Chronic non-specific neck pain is the most common chronic musculoskeletal paincondition, causing significant pain, disability, and lost productivity. On-specific neck pain is not just a clinical problem, it can develop into a complex disorder where physical, psychological, social compensation and other possible forces interact to cause and lead to maintained disability. Neck pain is present with weakness and muscular imbalance. It has a close relationship between muscle prone to tightness and those prone to inhibition. In the case of neck pain, there is tightness of upper trapezius (UT) muscle leading to middle trapezius (MT), lower trapezius (LT) and serratus anterior (SA) muscles weakness. There is evidence that scapulothoracic muscles weakness may also be associated with neck pain. Individuals with neck pain were having significantly weaker Lower Trapezius, Middle Trapezius and Serratus Anterior muscles strength than asymptomatic individuals.Context and Purpose: There is emerging evidence that scapulothoracic muscles weakness often is associated with neck pain and it has a close relationship between muscle prone to tightness and those prone to inhibition. In the case of neck pain, prolonged tightness of upper trapezius muscle can lead to middle trapezius, lowertrapezius, and serratus anterior muscles weakness. The purpose of the study is to find out the effect of LT, MT and SAmuscles strengthening along with the conventional treatment on pain, muscle strength and functional status in non-specifi cchronic neck pain. Results: There was significant effect on LT, MTand SA muscles strengthening in reducing pain, improving strength and functional status in individuals with non-specific chronic neck pain. Conclusion: Strengthening exercises to LT, MT and SA muscles along withconventional therapy is effective in reducing pain, improving muscle strength and functional status inindividuals with nonspecific chronic neck pain.

Isolated infraspinatus atrophy in elite volleyball player- Understanding the biomechanics, imaging and outcome

Over 800 million people worldwide play volleyball, either recreational or competitive. Even though all throwing athletes suffer from upper extremity injuries caused by overuse, volleyball additionally involves certain prototypical throwing biomechanics, not seen in other overhead sports. Complex biomechanics and the balanced interplay between the glenohumeral and scapulothoracic muscles ensure velocity and torque displacement in spike and jump-serve maneuvers (formerly known as smash) which are exclusive to volleyball. In this case report, we have described in detail the entity of isolated infraspinatus atrophy secondary to suprascapular nerve neuropathy.

Focus on the Scapular Region in the Rehabilitation of Chronic Neck Pain Is Effective in Improving the Symptoms: A Randomized Controlled Trial.

Chronic neck pain is a common human health problem. Changes in scapular posture and alteration of muscle activation patterns of scapulothoracic muscles are cited as potential risk factors for neck pain. The purpose of this study was to compare the effects of neck exercise training (NET) with and without scapular stabilization training (SST) on pain intensity, the scapula downward rotation index (SDRI), forward head angle (FHA) and neck range of motion (ROM) in patients with chronic neck pain and scapular dyskinesia. A total of sixty-six subjects with chronic neck pain and scapular dyskinesia were randomly divided into three groups: neck exercise training, n = 24, combined training (NET + SST), n = 24 and a control group, n = 24. Pain intensity, SDRI, FHA and ROM were measured by the numerical rating scale, caliper, photogrammetry and IMU sensor, respectively. When the combined intervention group consisting of NET and SST was compared with NET alone at six weeks, there was a statistically significant difference in pain intensity, SDRI, FHA and cervical ROM for flexion and extension (p ≤ 0.05). Adding scapular exercises to neck exercises had a more significant effect in decreasing pain intensity, SDRI, FHA and increased cervical ROM than neck exercises alone in patients with chronic neck pain. These findings indicate that focus on the scapular posture in the rehabilitation of chronic neck pain effectively improves the symptoms.

Scapula alata: Diagnosis and treatment by nerve surgery and tendon transfers

Scapula alata, also known as winged scapula, can lead to severe upper limb impairment. The shoulders’ function is altered because the scapula, which supports the upper limb, is no longer stable. Typical scapula alata is described for serratus anterior palsy; however, any scapulothoracic muscle impairment may lead to scapular winging, particularly trapezius palsy, which is easy to miss, thus needed to be considered as a differential diagnosis. The diagnosis is difficult and based on various clinical tests and a thorough examination as well as electroneuromyography and MRI. The treatment ranges from conservative treatments for spontaneous recovery, nerve surgery including neurolysis, nerve transfers and nerve grafts for acute cases, to tendon transfers for more chronic cases and when nerve procedures are no longer feasible. Tendon transfers in serratus anterior palsy produce excellent results with a high rate of patient satisfaction and are described with the sternal or clavicular head of the pectoralis major; we describe our preferred technique in this article. Tendon transfers in trapezius palsy are performed with the levator scapulae, rhomboid minor and major muscles. Our preferred method is the Elhassan triple transfer. Scapula alata is a frequent and often misdiagnosed condition. Appropriate management can yield excellent results. Patients should be referred right away to specialized centers for surgery if recovery is not spontaneous.

Effect of conscious abdominal contraction on the activation of periscapular muscles in individuals with subacromial pain syndrome

BackgroundSynergism between shoulder and trunk muscles seems to be effective to increase periscapular muscle activation in asymptomatic subjects. The influence of conscious contraction of the abdominal muscles has not yet been studied in non-athlete subjects with pain. The study aimed to investigate the effect of the instruction for conscious activation of the abdominal muscles on the activity of the scapulothoracic muscles during shoulder exercises in subjects with subacromial pain syndrome. MethodThirty subjects with unilateral pain (mean age 52 ± 11 years) participated in this study. Three isometric and five dynamic exercises for the scapulothoracic muscles were assessed. The group without instruction just repeated the exercises, while the instruction group was evaluated before and after conscious abdominal training. The linear mixed model analysis was used to compare the muscle activation between groups. FindingsDifferences between groups after the conscious abdominal contraction for activation of middle and lower trapezius on the symptomatic side in the “Full can”(p = 0.03; effect size:0.92 middle trapezius); (p = 0.02; effect size:0.96 lower trapezius) and “Knee Push” (p = 0.01; effect size:0.75 lower trapezius). For asymptomatic side, the exercises “External Rotation Kneeling” (p = 0.04; effect size: 0.81 lower trapezius); (p = 0.00; effect size: 2.09 serratus anterior), “Knee Push” (p = 0.04; effect size:1.24 serratus anterior) and “Wall Slide” (p = 0.01; effect size: 1.03 serratus anterior). InterpretationConscious contraction of the abdominal muscle immediately alter the activation of the serratus anterior muscle during closed kinetic chain exercises on the asymptomatic side and increased activation of trapezius on the symptomatic side during shoulder open kinetic chain exercise.

EMG activity of the serratus anterior and trapezius muscles during elevation and PUSH UP exercises

BackgroundElevation and push up (Pu) exercises are considered to be beneficial for the rehabilitation of shoulder complex pathology. Despite their clinical utility, there is a lack of evidence comparing scapulothoracic muscles recruitment during these exercises. ObjectiveTo evaluate the EMG activity of upper trapezius (UT), Lower Trapezius (LT), Upper Serratus anterior (USa) and Lower Serratus anterior (LSa) muscles during a variety of elevation and Pu exercises. MethodsThirteen healthy participants (non, athlete, male, mean ± standard deviation; age: 21.1 ± 1.8 years; height: 1.80 m ± 0.04; weight: 79 ± 12 kg) were assessed. EMG data was collected during Scaption, wall slide and elevation with external rotation (EleEr) with and without load. Pu classic, Pu plus (PuP) on stable/unstable surfaces and Pu with shoulder internal rotation were also assessed. ResultsUT had a significant higher activity during ‘Scaption load’ (p < .05) and LT in ‘EleEr load’ and ‘Scaption load’ (p < .05). USa and LSa had a significant higher activity on ‘PuP unstable surface’ and ‘PuP internal rotation’ compared to elevation exercises (p < .05). Scaption had greater activity ratio compared to the other exercises on UT/LT (p < .05). Pu variations had lower results in UT/USa and UT/LSa ratios compared to shoulder elevation exercises (p < .05). ConclusionsElevation exercises produce significant effects on upper and lower trapezius activation while Pu exercises on Sa muscles. Wall slide exercise notes the lowest activation in all muscles. A descending order of muscle activity during different variations of elevation and Pu exercises is provided in order to guide exercise selection in everyday clinical practice.

Mechanisms of Modulation of Automatic Scapulothoracic Muscle Contraction Timings

Erected posture provides humans a large shoulder mobility that requires complex automatic muscle synergies to accomplish joint stability needs. This is evident in shoulder abduction, wherein the voluntary activation of glenohumeral muscles is coupled with an automatic recruitment of scapulothoracic muscles. Here, we investigated whether volitional modification of the scapular position, and dynamic scapular elevation, modulate the contraction timing of five shoulder muscles (middle deltoid, upper, middle and lower fiber of the trapezius, serratus anterior) during shoulder abduction. The results show matched contraction timings of the deltoid and upper trapezius across the scapular positions, whereas the contraction timings of the middle and lower fibers of the trapezius change secondary to the scapular position. These results might reflect different central strategies to coordinate the automatic sequences of contraction of the scapulothoracic muscles. This suggest a flexible and adaptable predisposition of the motor control system in exploring alternative solutions to accomplish the functional movement needs, such as the fulfillment of unconstrained movements. Intriguingly, the shoulder abduction may represent a powerful, non-invasive, and straightforward tool to deepen the understanding of the neural basis underlying the voluntary motor command modulation of the out-of-volition automatic muscle contractions.