Article

Scapular asymmetry in participants with and without shoulder impingement syndrome; a three-dimensional motion analysis

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Abstract

Background: This study analyzed the dynamic three-dimensional scapular kinematics and scapular asymmetry in participants with and without shoulder impingement syndrome. Methods: Twenty-nine participants with shoulder impingement syndrome, have been suffering from unilateral shoulder pain at the dominant arm lasting more than six weeks and thirty-seven healthy controls participated in the study. Scapular kinematics was measured with an electromagnetic tracking device during shoulder elevation in the sagittal plane. Data for bilateral scapular orientation were analyzed at 30°, 60°, 90°, and 120° of humerothoracic elevation and lowering. The symmetry angle was calculated to quantify scapular asymmetry throughout shoulder elevation. Findings: Statistical comparisons indicated that the scapula was more downwardly rotated (p<0.001) and anteriorly tilted (p=0.005) in participants with shoulder impingement syndrome compared to healthy controls. Side-to-side comparisons revealed that the scapula was more anteriorly tilted on the involved side of participants with shoulder impingement syndrome (p=0.01), and the scapula was rotated more internally (p=0.02) and downwardly (p=0.01) on the dominant side of healthy controls. Although there were side-to-side differences in both groups, symmetry angle calculation revealed that the scapular movement was more asymmetrical for scapular internal and upward rotation in individuals with shoulder impingement syndrome when compared with healthy controls (p<0.05). Interpretation: The findings of the study increase our knowledge and understanding of scapular alterations in symptomatic and asymptomatic populations, which creates biomechanical considerations for shoulder assessment and rehabilitation.

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... The mobility and stabilization of the shoulder region depends on the functional integrity and organization of the musculoskeletal system [6][7][8]. Considering the shoulder's biomechanics, a difference in the movement of any of the joints composing the shoulder girdle hinders the normal upper limb movements and causes abnormal scapulohumeral rhythm [6][7][8]. ...
... The mobility and stabilization of the shoulder region depends on the functional integrity and organization of the musculoskeletal system [6][7][8]. Considering the shoulder's biomechanics, a difference in the movement of any of the joints composing the shoulder girdle hinders the normal upper limb movements and causes abnormal scapulohumeral rhythm [6][7][8]. Scapular asymmetry lead to biomechanical abnormalities and change periscapular muscle activity [8]. This can affect the position of joint and proprioception [9,10]. ...
... This can affect the position of joint and proprioception [9,10]. This situation leads to impaired functional integrity and organization of the shoulder joint, and it may cause various shoulder problems [6][7][8]. There is not any clear evidence about the relationship between scapular asymmetry and shoulder injuries and the causes of the possible relationship. ...
Article
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Introduction: Scapular asymmetry may affect the biomechanics of the shoulder girdle joints and muscles by changing the contraction angles of the muscles. The purpose of this prospective cohort, matched-controlled study was to compare shoulder muscle strength, proprioception sense and internal/external rotation flexibility between adolescent athletes with and without scapular asymmetry. Material and methods: Nineteen athletes of tennis, fencing, shooting, archery, gymnastics, and badminton branches with left side (non-dominant) scapular asymmetry were included in the study as asymmetry group. Nineteen athletes who have similar gender, sports branch, professional experience, physical characteristics with asymmetry group were included in the study as the control group. Scapular asymmetry was measured using a tape measure with the Lateral Scapular Slide Test. Shoulder horizontal abduction/adduction isokinetic muscle strength and shoulder abduction/adduction isometric muscle strength was tested by an isokinetic dynamometer. The proprioception sense of the glenohumeral joint was evaluated with a digital inclinometer, and the flexibility of the internal and external rotation of the shoulder was evaluated by the flexibility test. Results: There was not any significant difference between the groups in isokinetic muscle strength, isometric muscle strength, and proprioception sense of shoulder (p > 0.05). Shoulder internal rotation flexibility of both dominant and non-dominant sides was higher in the asymmetry group than the control group (p < 0.05). Conclusions: It was determined that the flexibility of shoulder internal rotation in adolescent athletes with scapular asymmetry was higher than those without asymmetry.
... We can verify that the reduction of the EMG activity of the LT was precisely in movements where in patients with SIS present the major alterations of movement, like abduction and elevation (Alizadehkhaiyat et al., 2018;Lewis et al., 2015;Phadke et al., 2009;Thelen et al., 2008). With this in mind, one supposition is that patients used another strategy of movement through other muscles, such as the middle trapezius, pectoralis minor, levator scapulae, and rhomboids (Escamilla et al., 2014;Ludewig and Braman, 2011;Phadke et al., 2009;Turgut et al., 2016), as the kinematics variables of upward rotation, lateral rotation, and posterior tilt did not show significant differences (p > 0,05). It should be noted that subjects with SIS demonstrated reduction in posterior tilt (McClure , 2006;Turgut et al., 2016), upward rotation (Ludewig and Braman, 2011;Ludewig and Reynolds, 2009;Shaheen et al., 2015;Turgut et al., 2016), increase in internal rotation (Lopes et al., 2015), and elevation of the clavicle (Lin et al., 2005;Ludewig and Braman, 2011;Ludewig and Cook, 2000;Ludewig and Reynolds, 2009). ...
... With this in mind, one supposition is that patients used another strategy of movement through other muscles, such as the middle trapezius, pectoralis minor, levator scapulae, and rhomboids (Escamilla et al., 2014;Ludewig and Braman, 2011;Phadke et al., 2009;Turgut et al., 2016), as the kinematics variables of upward rotation, lateral rotation, and posterior tilt did not show significant differences (p > 0,05). It should be noted that subjects with SIS demonstrated reduction in posterior tilt (McClure , 2006;Turgut et al., 2016), upward rotation (Ludewig and Braman, 2011;Ludewig and Reynolds, 2009;Shaheen et al., 2015;Turgut et al., 2016), increase in internal rotation (Lopes et al., 2015), and elevation of the clavicle (Lin et al., 2005;Ludewig and Braman, 2011;Ludewig and Cook, 2000;Ludewig and Reynolds, 2009). The findings of the present study corroborate with those of others in the literature that use of KT on glenohumeral did not find influence on the variables of the scapular kinematics (Alam et al., 2015;Keenan et al., 2016) while disagreeing with the findings of those who applied strips on the stabilizer muscles and found influence on the scapular kinematics (Hsu et al., 2009;Leong et al., 2016;Van Herzeele et al., 2013). ...
... With this in mind, one supposition is that patients used another strategy of movement through other muscles, such as the middle trapezius, pectoralis minor, levator scapulae, and rhomboids (Escamilla et al., 2014;Ludewig and Braman, 2011;Phadke et al., 2009;Turgut et al., 2016), as the kinematics variables of upward rotation, lateral rotation, and posterior tilt did not show significant differences (p > 0,05). It should be noted that subjects with SIS demonstrated reduction in posterior tilt (McClure , 2006;Turgut et al., 2016), upward rotation (Ludewig and Braman, 2011;Ludewig and Reynolds, 2009;Shaheen et al., 2015;Turgut et al., 2016), increase in internal rotation (Lopes et al., 2015), and elevation of the clavicle (Lin et al., 2005;Ludewig and Braman, 2011;Ludewig and Cook, 2000;Ludewig and Reynolds, 2009). The findings of the present study corroborate with those of others in the literature that use of KT on glenohumeral did not find influence on the variables of the scapular kinematics (Alam et al., 2015;Keenan et al., 2016) while disagreeing with the findings of those who applied strips on the stabilizer muscles and found influence on the scapular kinematics (Hsu et al., 2009;Leong et al., 2016;Van Herzeele et al., 2013). ...
Article
Objective To investigate the effects of Kinesio Taping® (KT) on scapular kinematics and electromyographic (EMG) activity in subjects with shoulder impingement syndrome (SIS). Methods Twenty subjects with a diagnosis of SIS performed abduction, scaption, and flexion movements in two load conditions: (1) without load and (2) holding a dumbbell. The same movements were evaluated again with the use of KT over the deltoid muscle with a 20% tension. Scapular kinematics data of the shoulder complex were captured with BTS SMART-DX at a frequency rate of 100 Hz. EMG activity was evaluated for the upper trapezius, lower trapezius, middle deltoid, and serratus anterior muscles with BTS FREE EMG 1000 at a frequency rate of 1000 Hz. The root mean square values normalized by the maximal voluntary contraction and the peak values of upward rotation, internal rotation, and posterior tilt were compared with the KT conditions through repeated-measures ANOVA (α = 0.05) using SPSS software. Results No significant differences between KT conditions were found for scapular kinematics (p > 0.05). For EMG activity, a reduction in the lower trapezius was found (p < 0.05) during abduction with load (p < 0.05) and elevation without load (p < 0.05). Conclusions According to the results of this study, it was not possible to verify changes in scapular kinematics in subjects with SIS. However, a reduction in EMG activity was observed for the lower trapezius muscle. Therefore, caution should be taken in prescribing KT for SIS subjects, who already have a reduction in EMG activity in this muscle, as KT may have an adverse effect.
... Throughout the recovery phase, the scapula maintained an upwardly rotated position, whilst reaching maximal internal rotation and minimal anterior tilt relatively early on. The scapulothoracic motions observed were consistent with previous unilateral observations in everyday wheelchair users [11][12][13] and also resembled orientations previously associated with shoulder pain in AB populations [7][8][9]27]. However, previous studies that identified relationships between scapular kinematics and pain in AB populations did so during tasks around or in excess of 90°shoulder elevation during static or controlled planar motions [7][8][9]27]. ...
... The scapulothoracic motions observed were consistent with previous unilateral observations in everyday wheelchair users [11][12][13] and also resembled orientations previously associated with shoulder pain in AB populations [7][8][9]27]. However, previous studies that identified relationships between scapular kinematics and pain in AB populations did so during tasks around or in excess of 90°shoulder elevation during static or controlled planar motions [7][8][9]27]. Given the low shoulder elevation exhibited during wheelchair propulsion it could be suggested that the biomechanics of ADL wheelchair propulsion is a relatively 'low risk' activity for the development of shoulder pain, especially in wheelchair athletes. ...
... It was also clear that the magnitude of these asymmetries was not significantly affected by increased propulsion speed and relationships to shoulder pain were again limited, even in individuals with unilateral shoulder pain, where greater asymmetries may have been anticipated. Although non-wheelchair specific studies have previously identified relationships between scapulothoracic asymmetry and shoulder impingement syndrome using moiré topography [10] and 3D kinematics [27], the ambiguity between individual asymmetries and shoulder pain currently observed could again suggest that this is not a definite risk factor for the development of pain for wheelchair athletes during ADL wheelchair propulsion and warrants further investigation. ...
Article
Background: Shoulder pain is the most common complaint for wheelchair athletes. Scapular orientation and dyskinesia are thought to be associated with shoulder pathology, yet no previous studies have examined the bilateral scapula kinematics of wheelchair athletes during propulsion. Research question: To examine bilateral scapular kinematics of highly trained wheelchair rugby (WR) players and any associations with self-reported shoulder pain during everyday wheelchair propulsion. Methods: Ten WR players (5 with shoulder pain, 5 without) performed 2 × 3-minute bouts of exercise in their everyday wheelchair on a wheelchair ergometer at two sub-maximal speeds (3 and 6 km h-1). During the final minute, 3D kinematic data were collected at 100 Hz to describe scapulothoracic motion relative to each propulsion cycle. Instantaneous asymmetries in scapular orientation between dominant and non-dominant sides were also reported. Differences in scapular kinematics and propulsion asymmetries were compared across shoulders symptomatic and asymptomatic of pain. Results: An internally rotated, upwardly rotated and anteriorly tilted scapula was common during wheelchair propulsion and asymmetries ≤14° did exist, yet minimal changes were observed across speeds. Participants with bilateral shoulder pain displayed a less upwardly rotated scapula during propulsion, however large inter-individual variability in scapular kinematics was noted. Significance: Scapular asymmetries are exhibited by wheelchair athletes during wheelchair propulsion, yet these were not exacerbated by increased speed and had limited associations to shoulder pain. This suggests that propulsion kinematics of highly trained athletes may not be the primary cause of pain experienced by this population.
... A recent study has shown that both involved and noninvolved shoulders have alterations in scapular kinematics in individuals with shoulder impingement. 16 Additionally, these symptomatic individuals had increased scapular asymmetry when compared to asymptomatic individuals. 16,17 Although there are many investigations conducted on the relationship between soft tissue tightness and shoulder kinematics, there is a lack of information concerning the dynamic properties responsible for side-to-side differences such as scapular asymmetry. ...
... 16 Additionally, these symptomatic individuals had increased scapular asymmetry when compared to asymptomatic individuals. 16,17 Although there are many investigations conducted on the relationship between soft tissue tightness and shoulder kinematics, there is a lack of information concerning the dynamic properties responsible for side-to-side differences such as scapular asymmetry. 10,14,15 It is not yet clear whether side-to-side pectoralis minor and posterior capsule flexibility deficits have an effect on the observed scapular asymmetry in asymptomatic and symptomatic individuals. ...
... The method suggested by Zifchock et al. 27 was used to define symmetry angle, to be able to quantify scapular asymmetry throughout arm elevation (at rest and at 30 • , 60 • , 90 • , 120 • of elevation, and at 120 • , 90 • , 60 • , 30 • of lowering) between involved and non-involved shoulders of the asymptomatic group or dominant and non-dominant shoulders of the asymptomatic group. The symmetry angle was calculated with the data obtained from each scapular kinematics variable identified previously at the same humerothoracic elevation angle by using the previously described formulae 16,25 : Furthermore, the symmetry angle obtained through the scapular internal/external rotation, the upward/downward rotation, and the anterior/posterior tilt at the each specific humerothoracic elevation angle was then averaged. The symmetry angle value of 0% indicated perfect symmetry while 100% indicated that the two values were equal and opposite in magnitude. ...
Article
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Background: Many studies have investigated the relationship between soft tissue tightness and shoulder kinematics. However, there is a lack of information on the dynamic properties responsible for side-to-side differences such as scapular asymmetry. Objective: To determine the relationship between a deficit in soft tissue flexibility and scapular asymmetry. Methods: A total of 58 individuals (29 patients with shoulder pain and 29 asymptomatic participants) were enrolled. Bilateral shortening of the pectoralis minor muscle and posterior shoulder tightness were assessed. Additionally, side-to-side flexibility deficit was calculated. Scapular kinematics were measured with an electromagnetic tracking device while individuals were standing in a resting position and during arm elevation. The symmetry angle was calculated to quantify scapular asymmetry. Results: The pectoralis minor and the posterior capsule flexibility deficit showed a significant positive relationship with the symmetry angle in the resting position separately for both asymptomatic (r=0.47, r=0.37 relatively) and symptomatic groups (r=0.58, r=0.38 relatively), indicating that the increased deficit in the pectoralis minor and posterior capsule flexibility were associated with increased scapular asymmetry. However, no significant relationship was found between flexibility deficit and scapular asymmetry during arm elevation and lowering for both asymptomatic and symptomatic groups. Conclusion: The findings of the study provided information on the relationship of a flexibility deficit on the scapular position and orientation in asymptomatic and symptomatic populations.
... Inclusion process is synthesized in Fig. 1. Six studies (Alizadehkhaiyat et al., 2018;Huang et al., 2016;Körver et al., 2014;Park and Park, 2019;Shinohara et al., 2014;Turgut et al., 2016c) were excluded during the full text assessment. Three (Huang et al., 2016;Körver et al., 2014;Turgut et al., 2016c) because there was no group comparison, two (Park and Park, 2019;Shinohara et al., 2014) because the population included did not meet the objectives of this review, and one (Alizadehkhaiyat et al., 2018) because measurement was performed during isometric task. ...
... Six studies (Alizadehkhaiyat et al., 2018;Huang et al., 2016;Körver et al., 2014;Park and Park, 2019;Shinohara et al., 2014;Turgut et al., 2016c) were excluded during the full text assessment. Three (Huang et al., 2016;Körver et al., 2014;Turgut et al., 2016c) because there was no group comparison, two (Park and Park, 2019;Shinohara et al., 2014) because the population included did not meet the objectives of this review, and one (Alizadehkhaiyat et al., 2018) because measurement was performed during isometric task. Finally, the 17 included studies observed a total of 943 participants, mean age of 35.6 ± 6.1 years. ...
Article
Background: Subacromial shoulder pain syndrome is a very common and challenging musculoskeletal disorder. Kinematics, electromyographic muscle activity and isokinetic dynamometry are promising non-invasive movement analysis tools to improve understanding of this condition. No review has combined their results to provide a better understanding of the effects of subacromial pain syndrome on shoulder movement. This systematic review aimed to synthesise the associations between exposure to shoulder pain due to subacromial pain syndromes or subacromial impingement and changes in shoulder movement measures. Methods: The databases were Scholar google, Pubmed, Science Direct, Scopus and the Cochrane Library. We included studies that observed the association of the presence of subacromial pain syndromes or subacromial impingement with changes in shoulder motion measures. Findings: Seventeen studies with 943 participants were included. The main kinematic change was a lower scapular posterior during abduction in the subacromial pain syndrome group with a "low" level of evidence (standardised mean difference = -0.61, 95% confidence interval [-0.80; -0.43]). The main electromyographic change was an earlier onset of activation of the upper trapezius in the subacromial pain syndrome group, with a "moderate" level of evidence (standardised mean difference = 1.01, 95% confidence interval: [-2.97; 0.96]). The main isokinetic change was a lower peak internal rotator torque in the subacromial pain syndrome group, with a 'low' level of evidence (standardised mean difference = -0.41, 95% confidence interval: [-0.53; -0.29]). Interpretation: The variables measured during movement are associated with subacromial pain syndrome or subacromial impingement syndrome. Consistency between the results supports the importance of scapula biomechanics measurements in these conditions.
... By performing the Flexion-EF, participants are required to actively mobilize their scapula into greater UR most likely through increased activation of the SA. This may prove useful among patients with SAIS who have been shown to present with decreased scapular UR, 33,34 decreased SA activation, 3 and increased activation of the UT. 3,35 The Flexion-EF may possess several advantages over other exercises purported to promote optimal scapular muscle activation ratios. ...
... 11,13 However, the Flexion-EF results in similar muscle activation effects while avoiding some of the undesirable effects of increased scapular protraction including hyperactivation of the deltoid and a decreased ability to generate shoulder muscle strength. 13,36,37 Finally, since Flexion-EF also resulted in increased scapular UR, it may possess a better choice in patients demonstrating diminished scapular UR. 3,33,34 A less expected finding of this study was the decreased activation of the UT during Flexion-EF. Castelein et al 38 similarly reported lower UT activation when shoulder elevation was performed with the elbow bent. ...
Article
Context: Decreased scapular upward rotation (UR) and diminished activation of the serratus anterior (SA) and lower trapezius (LT) are often observed among patients with subacromial impingement syndrome. Maintaining the elbow fully flexed during shoulder flexion may limit glenohumeral motion due to passive insufficiency of the triceps brachii and therefore facilitate greater scapular UR and increased scapular muscle activation. Objectives: To compare scapular UR, SA, upper trapezius (UT), middle trapezius, and LT activation levels between shoulder flexion with the elbow extended (Flexion-EE) to shoulder flexion with the elbow fully flexed (Flexion-EF). This study hypothesized that Flexion-EF would result in greater scapular UR, greater SA and LT activation, and a lower UT/SA and UT/LT activation ratio compared with Flexion-EE. Design: Cross-sectional study. Setting: A clinical biomechanics laboratory. Participants: Twenty-two healthy individuals. Main outcome measures: Scapular UR and electromyography signal of the SA, UT, middle trapezius, and LT, as well as UT/SA and UT/LT activation ratio were measured during Flexion-EE and Flexion-EF. Results: Flexion-EF resulted in greater scapular UR compared with Flexion-EE (P < .001). Flexion-EF resulted in greater SA activation, lower UT activation, and a lower UT/SA activation ratio compared with Flexion-EE (P < .001). Conclusions: Fully flexing the elbow during shoulder flexion leads to increased scapular UR primarily through greater activation of the SA. This exercise may be of value in circumstances involving diminished scapular UR, decreased activation of the SA, and an overly active UT such as among patients with subacromial impingement syndrome.
... A disturbed activation pattern of the scapula stabilizers is often found in patients with subacromial pain 16,18,25,77,94,105,145,159 . Patients with subacromial pain have less scapular movement (upward rotation, posterior tilt and external rotation) during arm elevation than healthy controls 147,159,160,162 . The difference may be the result of several mechanisms, including deficient scapular and rotator cuff muscle performance 14,18,94,105 , posterior capsule tightness 39,86,162 , shortening of the pectoralis minor 111,166,172 and an increase of thoracic spine flexion 86,95,119,162 . ...
... The three components chosen to use in clinical presentation were based on research by Clausen et al. (2017) 21 and Uhl et al. (2009) 160 , who showed their importance in clinical examination 21,161 . Our results show that the choice is justified, since 98% of the patients with subacromial pain presented with positive clinical findings in at least one of these three components. ...
... It was observed that 44% women and 56% of men were affected by shoulder impingement syndrome in the symptomatic group of patients [26]. In a narrative review to analyze the epidemiology shoulder syndrome, it was summarized that the ratio of male to female prevalence rates for the [25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44] year age groups were 23% and 13% respectively [27]. It was also observed that most of the individuals suffering from shoulder impingement syndrome were of normal BMI. ...
... Another case-control study was conducted to observe variation in the scapular position with shoulder impingement. For this purpose, 66 individuals were included and observed that almost all the individuals suffering from shoulder impingement syndrome were affected dominant side [31]. ...
Article
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Background: Shoulder impingement syndrome is the most pronounced cause of shoulder pain and disability. It is the entrapment of subacromial content in the shoulder outlet. Howoever, entrapment could be caused by a number of bony and soft tissue defects. However, Ultrasound is the modality of choice for the diagnosis and differentiation of these various causes of shoulder impingement syndrome.
... Different conditions of shoulder pain are frequently associated with alterations in scapular kinematics (Hebert et al., 2002;Kijima et al., 2015;Lawrence et al., 2014;Ludewig and Cook, 2000;Lukasiewicz et al., 1999;McClure and Michener, 2015;Mell et al., 2005;Ogston and Ludewig, 2007;Turgut et al., 2016). These alterations typically include increased scapular internal rotation, decreased scapular upward rotation and decreased posterior tilt (Hebert et al., 2002;Lawrence et al., 2014;Ludewig and Cook, 2000;Lukasiewicz et al., 1999). ...
... Alterations in scapular kinematics such as decreased upward rotation and posterior tilt, and increased internal rotation have already been described in individuals with shoulder pain (Hebert et al., 2002;Ludewig and Cook, 2000;Ludewig and Reynolds, 2009;Lukasiewicz et al., 1999;Turgut et al., 2016). The SAT is performed to assist scapular upward rotation and posterior tilt during active and dynamic elevation of the arm in individuals with shoulder pain. ...
Article
Background: The Scapular Assistance Test was suggested to directly assess the influence of scapular motion on pain and indirectly measure the function of the scapular rotators. However, it is still not clear if individuals with a positive Scapular Assistance Test actually present changes in scapular motion and muscle strength. This study compared scapular kinematics and muscle strength between those with a positive Scapular Assistance Test and those with a negative Scapular Assistance Test. Methods: Fifty individuals with shoulder pain were randomly allocated to: positive (n = 25) or negative Scapular Assistance Test (n = 25) group. Scapular kinematics was measured during elevation and lowering of the arm. Strength of the serratus anterior and lower trapezius was also measured. Two-way analysis of variance was used to compare kinematics between groups. Unpaired Student's t-test and Mann-Whitney test were used to compare strength of serratus anterior and lower trapezius, respectively. Findings: There were no differences (P > 0.05) in scapular internal rotation and upward rotation between both groups. For scapular tilt, there was group main effect (P < 0.05) during elevation and lowering of the arm, whereas the positive Scapular Assistance Test group presented greater scapular anterior tilt. There was no difference (P > 0.05) in strength between groups. Interpretation: Individuals with a positive Scapular Assistance Test are more likely to present decreased scapular posterior tilt in those with shoulder pain. Strength of the scapular muscles seems to be same in those with a positive and a negative Scapular Assistance Test.
... Further, shortened internal rotator muscles combined with weak external rotator muscles can also lead to a narrowing of the subacromial space and subsequent impingement [25]. Individuals with impingement were reported to have a more downward rotated and anterior tilted scapula, and often demonstrate more asymmetry in scapular motion when compared to healthy individuals [26]. ...
... Since the scapula bones are connected to the spine by muscles and ribs, it can be expected that any change in the position of the spine and shoulder girdle can lead to a change in the position of the shoulder [5,6]. In this regard, various studies people with shoulder impingement or healthy people, including overhead athletes have emphasized the asymmetry of the shoulders [7][8][9]. ...
Article
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Background and Aims: Daily living activities require the composition and coordination of scapulothoracic and glenohumeral joints. In athletes, the position of the scapula have a direct effect on their athletic performance due to its relationship with shoulder function. This study aims to investigates the scapulohumeral rhythm, kyphosis and forward shoulder in Iranian Wushu athletes and non-athletes. Methods: This is a quasi-experimental study. Participants were 27 wushu athletes (Age: 23.29±1.72 years, height: 1.72±0.20 m, weight: 69.50±11.50 kg, body mass index: 22.25±3.29 kg/m2) and 27 non-athletes (Age: 25.92±2.85 years, height: 1.75±0.07 m, weight: 69.36±11.73 kg, body mass index: 22.53±3.08 kg/m2) which were selected using a convenience sampling method. The kyphosis angle was assessed with a flexible ruler and the forward shoulder was assessed using the photographic method. The distance of the scapula from the spine was assessed using the lateral scapular slide test. Independent t-test was used to examine the differences between the groups, and Pearson correlation test was used to examine the relationship between the study variables. Statistical analysis was performed in SPSS software, version 24. The significance level was set at 0.05. Results: The angles of kyphosis and forward shoulder had a significant relationship with the distance of the scapula from the spine at 0, 45 and 90 degrees of arm abduction (P≥0.05) such that with increasing kyphosis and forward shoulder angles, the distance increased. In non-athletes, there was a significant difference between the distances of dominant and non-dominant scapula from the spine in 0 degree (P=0.01) and 45 degrees (P=0.02) of arm abduction; in 90 degrees, no significant difference in non-athletes was observed. Results of independent t-test showed a significant difference in kyphosis and forward shoulder angles and in the distance of the scapula from the spine at different degrees of arm abduction between the two groups (P≤0.05), which were greater in athletes than in non-athletes. Conclusion: The kyphosis and forward shoulder angles have a relationship with the position of the scapula on the spine in professional Wushu athletes. More attention should be paid to these changes and their evaluation in terms of injury and musculoskeletal disorders.
... Six études (154-159) ont été exclues lors de la lecture de l'intégralité des articles. Trois d'entre elles(154,156,157) car elles ne comparaient pas les groupes entre eux, deux (155,159) parce qu'elles incluaient une population qui ne correspondait pas aux critères d'inclusion de la revue, et une (158) parce que la tâche durant laquelle avait lieu la mesure était isométrique. Les études incluses ont recueilli les résultats de 943 participants, d'âge moyen de 35,6 ± 6,1 ans. ...
Thesis
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Un soignant sur deux déclare avoir des douleurs de l’épaule au cours de sa carrière, malgré les connaissances actuelles sur les structures de l’épaule et leurs pathologies. Une meilleure compréhension des mouvements de l’épaule pathologique semble compléter ces connaissances pour améliorer l’offre de prévention et de soin de ces pathologies. Cette thèse avait pour but d’améliorer la compréhension du syndrome de douleurs sous-acromiales en utilisant des méthodes de quantification du mouvement auprès de professionnels de santé hospitaliers.Une première partie a exposé à travers un travail bibliographique la complexité des troubles musculosquelettiques de l’épaule dans un contexte de travail. Des pistes d’amélioration de la compréhension de ces pathologies ont été apportées avec la présentation de méthodes d’évaluation du mouvement.Une deuxième partie présente le travail expérimental mené, portant sur l’évaluation des mouvements de l’épaule atteinte de syndrome de douleurs sous-acromiales. Une revue systématique de la littérature portait sur la population générale et une étude transversale s’est concentrée sur une population de soignants du bassin ébroïcien.Les résultats de ces travaux ont montré avec un niveau de preuve faible à modéré que la bascule postérieure de la scapula, le délai d’activation du trapèze supérieur et le couple de force en rotation médiale étaient des variables altérées chez les participants symptomatiques. Ils suggèrent également que l’épaule des soignants symptomatiques présente une hyperactivité musculaire. Les altérations de la bascule postérieure de la scapula peuvent ainsi être associées au raccourcissement du délai d’activation du trapèze supérieur. L’hyperactivité de la musculature de l’épaule peut être interprétée comme une surcharge sur les structures musculosquelettiques.Une troisième partie discute les observations réalisées chez les soignants comparativement à celles réalisées dans la population générale. Ce travail aboutit à des propositions de conduites à tenir pour la prévention et les soins à apporter auprès d’une population de soignants susceptible d’être atteinte de syndrome de douleurs sous-acromiales.
... Turgut et al observed asymmetry of scapular kinematics between the involved and uninvolved shoulder in patients with SIS and reported increased protraction, downward rotation, and anterior tilting of the scapula in the involved shoulder. [26] In this study, patients with SIS showed combined asymmetry of the scapular position in the resting posture and limited extension of the thoracic spine Table 2 Comparative analysis of shoulder range of motion between groups. during dynamic motion. ...
Article
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The motions of the shoulder are mainly carried out through the glenohumeral joint, but are also assisted by the scapulothoracic joint. Therefore, changes in the biomechanics of the thoracic spine and scapula affect the function of the shoulder. However, there is limited information on the biomechanical and functional characteristics of the shoulder complex and thoracic spine in patients with subacromial impingement syndrome (SIS). In this study, the biomechanical and functional characteristics of the shoulder complex and thoracic spine were analyzed in patients with SIS compared to healthy individuals. A total of 108 participants were included in this study. Participants were classified into 2 groups, the SIS (n = 55) and healthy (n = 53) groups. The shoulder and thoracic range of motion (ROM), scapular position, and isokinetic shoulder strength were measured in all participants. The shoulder ROM was significantly decreased in the SIS group compared to the healthy group (P < .001). The thoracic spine ROM showed significantly limited extension in the SIS group (P < .001). The scapular position showed significantly increased anterior tilting (P = .005), internal rotation (P = .032), protraction (P < .001), and decreased upward rotation (P = .002) in the SIS group. The isokinetic shoulder external rotation (P < .001) and abduction (P < .001) strength were significantly lower in the SIS group. Patients with SIS showed reduced shoulder ROM and end-range extension of the thoracic spine compared to healthy individuals, and the scapula was in a more anterior-tilted, protracted, and downward rotated position. In addition, it showed lower external rotation and abduction strength. These results suggest the need for interventions to improve the limited thoracic extension and altered scapular position, which may affect shoulder ROM and muscle strength in the rehabilitation of patients with SIS.
... Rossi (22,26). Range of motion of over 130°in arm elevation was considered an inclusion criterion in four of the studies (21,25,27,28). The other studies did not report the minimum range of elevation for inclusion. ...
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Context: With a key role in normal shoulder function, scapular kinematics have been investigated in shoulder impingement syndrome (SIS). Objectives: This systematic review aimed at determining scapular kinematic patterns in patients with SIS compared to in asymptomatic individuals. Data Sources: Databases such as PubMed, Scopus, Web of Science, Ovid, Embase and PEDRO were searched from January 1995 to June 2021. Study Selection: Articles in English published in peer-reviewed journals and using motion analysis systems to compare scapular kinematics between patients with SIS and asymptomatic subjects during arm elevation were included. Data Extraction: A modified Downs and Black checklist was used to assess the risk of bias of the included studies. A random-effects model was employed to perform a meta-analysis. Results: Nine out of 1650 screened abstracts were included for data extraction. Scapular upward rotation significantly decreased during arm elevation in SIS (SMD = -0.13, 95% CI = -0.23 to -0.02) with a low effect size (I2 = 46%). No differences were observed in scapular posterior tilt (SMD = -0.07, 95% CI = -0.18 to 0.03) and external rotation (SMD = 0.02, 95% CI = -0.06 to 0.09) between patients with SIS and asymptomatic subjects. Conclusions: This review revealed that except for scapular upward rotation, scapular movement was generally insignificantly different between the subjects with and without SIS during arm elevation. Between-group differences might have been overlooked as a result of the high risk of bias in the included studies. The high-quality studies addressing confounders are required to provide a definitive conclusion on the relationship between SIS and scapular kinematics.
... Page 2 of 11 Nomura et al. BMC Sports Science, Medicine and Rehabilitation (2022) 14:76 during upper extremity movement occurs in patients with SLAP lesions [3], subacromial impingement syndrome [4,5], and internal impingement of the shoulder [6,7]. In particular, Mihata et al. [7] reported that an increased scapular internal rotation angle and downward rotation angle at the maximum shoulder external rotation (MER) of simulated baseball pitching caused internal impingement of the shoulder in vitro. ...
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Background A baseball pitcher with decreased scapular control may not be able to achieve suitable scapular motion at maximum shoulder external rotation (MER) of baseball pitching during the pitching action. It is common clinically to compare scapular control of the throwing and non-throwing arms to detect side-to-side differences. However, it remains unclear whether scapular control is different between the throwing and non-throwing arms. Moreover, no data exist on the relationship between scapular control and scapular motion at MER of pitching. Primarily, this study aimed to compare scapular control during isometric shoulder flexion between the throwing and non-throwing arms. Secondly, this study aimed to investigate the relationship between scapular control during isometric shoulder flexion and scapular motion at MER of pitching. Methods Fifteen healthy collegiate baseball pitchers (age, 20.2 ± 1.9 years; height, 1.76 ± 0.05 m; body mass, 73.3 ± 6.7 kg) were recruited. An optical motion tracking system was used to assess scapular motion. Scapular control was defined as the amount of change in the scapular internal rotation angle, downward rotation angle, and anterior tilt angle during isometric shoulder flexion. We assessed scapular position at MER of pitching. Results No significant differences were detected for any of the scapular angles during isometric shoulder flexion between the throwing and non-throwing arms. The amount of change in the scapular internal rotation angle, scapular downward rotation angle, and scapular anterior tilt angle during isometric shoulder flexion had a significant relationship with the scapular downward rotation angle at MER. Conclusions No side-to-side difference was noted in scapular control during isometric shoulder flexion in healthy collegiate baseball pitchers at the group level. Further studies are required to understand the side-to-side differences at the individual level. Additionally, there was a relationship between scapular control during isometric shoulder flexion and scapular position at MER. These findings suggest that clinicians may consider using isometric shoulder flexion to assess scapular control in baseball pitchers.
... Com esse aumento, especula-se que possa levar a alterações na cinemática escapular e consequentemente prevenir uma patologia no ombro [3,18]. Apesar desta diminuição da atividade EMG do TD ser algo considerado benéfico na prevenção e reabilitação de pacientes, ainda assim não sabemos se tal resultado é proveniente de uma mudança na cinemática escapular, o que consequentemente geraria uma alteração da atividade EMG do TD, ou ainda, se com a aplicação da bandagem, promoveria a inibição pelo mecanismo proprioceptivo [8,34] e resultaria numa mudança no engrama motor do movimento, fazendo com que outros músculos periescapulares (trapézio médio, peitoral menor, levantador da escápula) compensassem o movimento realizado [38,39]. ...
Article
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Introdução: A bandagem elástica é uma fita elástica adesiva utilizada na prevenção e reabilitação do complexo do ombro. Entretanto, existem divergências na literatura sobre seus efeitos na atividade eletromiográfica dos músculos periescapulares durante exercícios com carga. Objetivo: Avaliar os efeitos da bandagem elástica na atividade eletromiográfica de músculos periescapulares durante o movimento de flexão do ombro sem carga e com halter em indivíduos saudáveis. Métodos: Vinte e seis indivíduos do sexo masculino realizaram o movimento de flexão do ombro sem carga e com halter com a bandagem elástica sobre o trapézio descendente. Foram avaliadas as atividades eletromiográficas de trapézio descendente, trapézio ascendente e serrátil anterior. São comparados os valores de pico e RMS em percentual da contração isométrica voluntária máxima através da ANOVA One Way. Resultados: Na flexão de ombro com halter ocorreu diminuição do pico da atividade eletromiográfica do trapézio descendente (p = 0,035). Não houve influência sobre os demais músculos periescapulares (p > 0,05). Conclusão: A bandagem elástica diminuiu o pico da atividade eletromiográfica do trapézio descendente durante a flexão do ombro com halter. Pode-se aplicar este resultado na prevenção de indivíduos que podem tender a aumentar a atividade do trapézio descendente.
... Ten studies evaluated pain before and after exercise interventions. 3,6,28,29,32,[37][38][39]41,46 Four studies measured pain using the visual analog scale; in 3 of these studies, significant effects of therapeutic exercise on pain were reported. 3,6,29 Although Struyf et al 39 reported no change in resting pain after exercise therapy, they reported a significant reduction of pain during movement (P < .004) ...
Article
Background: Therapeutic exercise for scapular muscles is suggested to be effective in reducing shoulder pain in patients with rotator cuff disorders, whereas its effectiveness on scapular position and motion has remained unclear. Therefore, the aim of this systematic review was to investigate whether exercise therapy improves scapular position and motion in individuals with scapular dyskinesis. Methods: This study is a wide systematic review including any type of clinical trial in which the effect of any type of therapeutic exercise, including scapular muscle strengthening, stretching, and scapular stabilization exercise, is investigated in adult participants. Results: Twenty studies were included in this systematic review. Studies were categorized on the basis of the techniques they used to measure scapular position and motion and the included participants. Methodologic quality of the studies was assessed by the Cochrane tool of assessing the risk of bias. Eight studies used 3-dimensional techniques for measuring scapular motions. Among them, 5 studies showed significant effects of exercise on scapular motion, of which 3 studies investigated individuals with subacromial impingement syndrome (SIS). The other 12 studies used 2-dimensional measurement techniques, of which 8 studies reported significant effects of exercise on scapular position and motion both in SIS patients and in asymptomatic individuals. However, their methodologic quality was debatable. Therefore, there was conflicting evidence for the effect of exercise on scapular dyskinesis. Conclusion: There is a lack of evidence for beneficial effects of exercise in improving scapular position and motion in individuals with scapular dyskinesis. However, exercise is beneficial in reducing pain and disability in individuals with SIS.
... The alterations in the scapular position and orientation have been clinically defined as the scapular dyskinesis, which affects shoulder function and performance; however, no direct relationship has been shown between the scapular motion deficit and existence of shoulder pain or risk factor for shoulder injury (Kibler, Sciascia, & Wilkes, 2012). Regarding anatomical relationships, a decrease in scapular upward rotation and posterior tilt results in a reduced subacromial space width, contributing to the development of subacromial impingement symptoms (Brossmann et al., 1996;Michener, McClure, & Karduna, 2003;Turgut, Duzgun, & Baltaci, 2016). An inappropriate scapular posterior tilt results in an inadequate elevation of the anterior acromion during shoulder movements, therefore decreases the subacromial space (Brossmann et al., 1996). ...
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Adult overhead athletes without a history of shoulder injury show scapular adaptations. There is a lack of detailed assessment of scapular kinematics in junior overhead athletes. This study aims to investigate three-dimensional scapular kinematics in junior overhead athletes. We recruited a total of 20 junior tennis players and 20 healthy children without participation in any overhead sports in this study. Bilateral scapular kinematic data were recorded using an electromagnetic tracking device for scapular plane glenohumeral elevation. The data were further analysed at 30°, 45°, 60°, 90° and 120° during glenohumeral elevation and lowering. Statistical comparisons of the data between groups (junior overhead athletes and non-overhead athletes) and sides (serve dominant and non-dominant shoulders of the overhead athletes) were analysed with the ANOVA. Comparisons showed that, in general, the scapula was more upwardly rotated and anteriorly tilted in overhead athletes when compared to non- overhead athletes, however there was no side-to-side di erences when serve dominant and non-dominant shoulders compared in junior overhead athletes. The serve dominant arm of junior overhead athletes had alternations in scapular kinematics when compared with the non-overhead athletes. These ndings provide clinical evaluation implications and the need for clinicians to assess for potential adaptations in junior overhead athletes.
... Five sensors with dimensions of 1.9 × 3.3 × 3.5 cm were used for the analysis. Sensors were bilaterally attached using double-sided tape to the posterior edge of the acromion, the insertion of the deltoid muscles and the first thoracic vertebra (Turgut et al., 2016;Thigpen et al., 2006), and then they were also fixed in the inflexible band (Fig. 1a). ...
Article
Background The relation between shoulder pain and scapular movement impairments is still unclear. The scapular assistance test (SAT) assesses the influence of shoulder pain on abnormal scapular movement or positions. This study aimed to investigate scapular kinematics during arm raising/lowering with and without elastic resistance in volleyball players with positive and negative SAT. Methods Scapular kinematics of twenty-six volleyball players with Scapular Dyskinesis (13 positive SAT, 13 negative SAT) was measured during shoulder abduction, flexion, and scaption under loaded and unloaded conditions. 3D scapular kinematics were recorded using Vicon motion capture system by an Acromial Marker Cluster. Results The main findings revealed that in the unloaded condition, participants with a positive SAT showed significant decrease in scapular posterior tilt in 60–90 degrees of arm raising in the scapular plane, compered to negative SAT. Conclusions It can be concluded that the combination of pain and dyskinesia may alter scapular posterior tilt during shoulder elevation in scapular plane without elastic resistance; but this does not alter the scapular upward and external rotation.
Article
Backgroud: Reliable scapular upward rotation and anterior-posterior tilt data are required for patients with subacromial impingement syndrome (SIS). Only a few studies have explored the reliability of such measurements derived using a modified inclinometer. Objectives: To determine the relative and absolute reliability of scapular upward rotation and anterior-posterior tilt measurements derived using a modified digital inclinometer in patients with SIS. Method: Seventeen SIS patients were assessed twice within 1 week. We determined the relative and absolute measurement reliability by calculating the intraclass correlation coefficient (ICC), standard error of measurement (SEM), and minimal clinically important difference (MCID). Both intra- and interrater reliability were determined. Results: The intra-rater reliability (both measurements) was high (0.72-0.88), and the interrater ICC was high to excellent (0.72-0.98). Clinically acceptable SEM and MCID values were obtained for scapular upward rotation (SEM: 4.28-9.33∘, MCID: 5.1-11.3∘) and anterior-posterior tilt (SEM: 3.72-7.55∘, MCID: 2.5-10.8∘). Conclusions: Measurements of scapular upward rotation and anterior-posterior tilt using a modified digital inclinometer reliably reveal scapular position and kinematics in patients with SIS.
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Objetivo: Comparar la actividad electromiográfica de la musculatura superficial escapulohumeral entre los tres planos de elevación de hombro: sagital, escapular y frontal. Métodos: Se realizó un estudio observacional, analítico, de corte transversal. Trece participantes realizaron una elevación y descenso de hombro en los tres planos. Durante estas elevaciones, se midió la cinemática del hombro con un sistema de captura de movimiento 3D. Sincrónicamente, se registró la actividad electromiográfica del músculo serrato anterior, de las tres porciones del músculo deltoides (anterior, medio y posterior) y trapecio (superior, medio e inferior). Se comparó la actividad muscular entre los tres planos a través de una prueba de Friedman o Skillings-Mack, según ausencia o presencia de datos perdidos. Resultados: Las porciones anterior y posterior del músculo deltoides (anterior y posterior) y el trapecio medio mostraron diferencias entre los planos de elevación (p<0.05). La porción media del deltoides se activó más en el plano frontal, al inicio de la elevación (p<0.05). Los demás músculos no mostraron diferencias entre los distintos planos. Conclusión: Los músculos deltoides anterior y posterior y trapecio medio modifican su activación en la elevación de hombro en distintos planos. Esta información puede orientar la selectividad muscular de ejercicios utilizados en la rehabilitación de la articulación escapulohumeral.
Article
Background Scapular kinematics of breast cancer survivors are most often evaluated during arm elevation. However, known compensations exist during functional task performance. The purpose of this study was to determine if scapular kinematics of breast cancer survivors during arm elevation are related to scapular kinematics during functional task performance. Methods Scapular kinematics of 25 non-cancer controls and 25 breast cancer survivors (split by presence of impingement pain) during arm elevation in 3 planes and 3 reaching and lifting functional tasks were measured. Scapular upward rotation and scapulohumeral rhythm (SHR) at 30° increments of arm elevation were calculated. Between-group differences of upward rotation during arm elevation were evaluated with one-way ANOVAs (p < 0.05). The association of upward rotation angle and SHR during arm elevation and functional tasks was tested with Pearson correlations (p < 0.05). Findings Scapular upward rotation was reduced for the breast cancer survivor with pain at lower levels of arm elevation in each plane by up to 7.1° (p = .014 to 0.049). This is inconsistent with functional task results, in which upward rotation decrements occurred at higher levels of arm elevation. Upward rotation angles and SHR during arm elevation had an overall weak-to-moderate relationship (r = 0.003 to 0.970, p = .001 to 0.048) to values from functional tasks. Arm elevation during sagittal plane elevation demonstrated scapular upward rotation that was most closely associated to upward rotation during functional task performance. Interpretation Inconsistent relationships suggests that clinical evaluations should adopt basic functional movements for scapular motion assessment to complement simple arm elevations.
Article
Background Round shoulder posture (RSP) is one of the potential risks for shoulder impingement syndrome (SIS) due to alignment deviation of the scapula. Evidence on how the characteristics of a shoulder brace affecting the degree of RSP, shoulder kinematics, and associated muscle activity during movements is limited. Research question The purposes of this study were (1) to compare the effects of a shoulder brace on clinical RSP measurements, muscle activities and scapular kinematics during arm movements in subjects with shoulder impingement syndrome (SIS) and RSP; and (2) to compare the effects of two configurations (parallel and diagonal) and two tensions (comfortable and forced tension) of the brace straps on muscle activities and scapular kinematics during arm movements in subjects with SIS and RSP. Methods Twenty-four participants (12 males; 12 females) with SIS and RSP were randomly assigned into 2 groups (comfortable then forced, and forced then comfortable) with 2 strap configurations in each tension condition. The pectoralis minor index (PMI), acromial distance (AD) and shoulder angle (SA) were used to assess the degree of RSP. Three-dimensional electromagnetic motion analysis and electromyography were used to record the scapular kinematics and muscle activity during arm movements. Results All clinical measurements with the brace were significantly improved (p < 0.05). Under forced tension, muscle activities were higher with the diagonal configuration than with the parallel configuration in the lower trapezius (LT) (1.2–2.3% MVIC, p < 0.05) and serratus anterior (SA) (2.3% MVIC, p = 0.015). For upward rotation and posterior tilting of the scapula, the diagonal configuration was larger than the parallel configuration (1.5°, p = 0.038; 0.4°–0.5°, p < 0.05, respectively). Significance Different characteristics of the straps of the shoulder brace could alter muscle activity and scapular kinematics at different angles during arm movement. Based on the clinical treatment preference, the application of a shoulder brace with a diagonal configuration and forced tension is suggested for SIS and RSP subjects.
Article
Background: Breast cancer survivors may encounter upper limb morbidities post-surgery. It is currently unclear how these impairments affect arm kinematics, particularly during functional task performance. This investigation examined upper body kinematics during functional tasks for breast cancer survivors and an age-matched control group. Methods: Fifty women (aged 35-65) participated: 25 breast cancer survivors who had undergone mastectomy and 25 age-range matched controls. Following basic clinical evaluation, including shoulder impingement tests, motion of the torso and upper limbs were tracked during six upper limb-focused functional tasks from which torso, scapular, and thoracohumeral angles were calculated. Between-group differences were evaluated with independent t-tests (p < .05). The breast cancer group was then divided based upon impingement tests and differences between the three new groups were tested with one-way ANOVAs (p < .05). Findings: Breast cancer survivors had higher disability scores, lower range of motion, and lower performance scores. The largest kinematic differences existed between the breast cancer survivors with impingement pain and the two non-pain groups. During overhead tasks, right peak scapular upward rotation was significantly reduced (d = 0.80-1.11) in the breast cancer survivors with impingement pain. This group also demonstrated trends of decreased peak humeral abduction and internal rotation at extreme postures (d = 0.54-0.78). These alterations are consistent with kinematics considered high risk for rotator cuff injury development. Interpretation: Impingement pain in breast cancer survivors influences functional task performance and may be more important to consider than self-reported disability when evaluating pain and potential injury development.
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Objective To determine the potential differences in both scapular positioning and scapular movement between the symptomatic and asymptomatic contralateral shoulder, in patients with unilateral subacromial pain syndrome (SAPS), and when compared with participants free of shoulder pain. Setting Three different primary care centres. Participants A sample of 73 patients with SAPS in their dominant arm was recruited, with a final sample size of 54 participants. Primary outcome measures The scapular upward rotation (SUR), the pectoralis minor and the levator scapulae muscles length tests were carried out. Results When symptomatic shoulders and controls were compared, an increased SUR at all positions (45°, 90° and 135°) was obtained in symptomatic shoulders (2/3,98/8,96°, respectively). These differences in SUR surpassed the minimal detectable change (MDC95) (0,91/1,55/2,83° at 45/90/135° of shoulder elevation). No differences were found in SUR between symptomatic and contralateral shoulders. No differences were found in either pectoralis minor or levator scapulae muscle length in all groups. Conclusions SUR was greater in patients with chronic SAPS compared with controls at different angles of shoulder elevation.
Article
The aim of this study is to investigate the effects of scapular taping on scapular kinematics by three-dimensional electromagnetic system during shoulder elevation in facioscapulohumeral muscular dystrophy patients. A total of 11 patients with facioscapulohumeral muscular dystrophy were included in the study. Scapular anterior-posterior tilt, upward-downward rotation, and internal-external rotations were evaluated using the three-dimensional electromagnetic system during the elevation of the upper limbs in the scapular plane before and after kinesio taping. For maximum humerothoracic elevation, there were no differences between the patients before and after taping on both dominant (p = 0.72) and non-dominant sides (p = 0.64). For scapular internal rotation, upward rotation, and posterior tilt, there were no differences between patients before and after taping during humerothoracic elevation on both dominant and non-dominant sides (p > 0.05). These results showed us that the excessive and abnormal movements of the scapula observed during the humeral elevation in facioscapulohumeral muscular dystrophy patients cannot be supported with flexible methods like kinesio taping. Therefore, we recommend to evaluate the scapula position by applying flexible and rigid taping to the patients who can reach over 90o in humerothoracic elevation in future studies.
Article
[Purpose] The purpose of this study was to investigate the effects of the plane of arm elevation on the scapulohumeral rhythm of scapular tilt in healthy persons. [Participants and Methods] An optical motion tracking system and acromion marker cluster were used to assess the scapulohumeral rhythm of scapular tilt in the coronal, sagittal and scapular planes during elevation of the arm of fourteen healthy male college students. [Results] The scapulohumeral rhythm of scapular tilt was 1.9 ± 0.4:1 for abduction, 1.8 ± 0.5:1 for scaption, and 1.8 ± 0.4:1 for flexion. During the arm elevation phase, the plane of arm elevation didn’t affect the scapulohumeral rhythm of scapular tilt. [Conclusion] Regardless of the plane of arm elevation, it is possible to use the 2:1 ratio of scapulohumeral rhythm of scapular tilt as a clinical indicator.
Article
Objective: The purpose of this study was to describe the three-dimensional deformities of midshaft clavicle fractures, which had been treated nonoperatively, using computed tomography (CT) surface matching. Methods: Twenty-one patients with unilateral midshaft clavicle fracture, who had been treated nonoperatively, were enrolled and evaluated retrospectively. The three-dimensional deformity of the fractured clavicle was evaluated by CT surface matching. CT scans of 21 age- and sex-matched patients with initial traumatic shoulder dislocation or proximal humeral fracture were enrolled as a control group, and the differences in three-dimensional deformities and lengths of the clavicles between the fracture group and the control group were evaluated. A correlation analysis was also performed between rotational deformities and clavicular length shortening. Results: The affected clavicle showed 1.3 ± 6.9 degrees of downward angular deformity, 2.1 ± 8.0 degrees of anterior angular deformity, and 5.0 ± 4.9 degrees of anterior rotational deformity. Compared with the control group, the fractured clavicle showed larger anterior rotational deformity (P = 0.021). Shortening of the clavicle demonstrated negative correlation with anterior axial rotation (R = -0.534, P = 0.013), but no correlation was found between clavicular shortening and the other two rotational deformities. Conclusion: In cases of midshaft clavicle fracture, the distal fragment usually rotates anteriorly due to its anatomical relationships. Shortening deformity following clavicle fracture was reported to change shoulder kinematics, and anterior rotational deformity might adversely affect scapular motion.
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Study design: Clinical measurement. Objective: To establish trial-to-trial within-day and between-day reliability, standard error of measurement, and minimal detectable change of scapular orientation during elevation and lowering of the arm, and with the arm relaxed at the side, in individuals with and without shoulder impingement. Background: Electromagnetic devices are commonly used to measure 3-D scapular kinematics during arm elevation in different conditions and for intervention studies. However, there is a lack of studies that evaluate within- and between-day reliability of these measurements. Methods: The subjects were allocated to either a control group or an impingement group. Kinematic data were collected using the Flock of Birds electromagnetic device during elevation and lowering of the arm in the sagittal plane on 2 different occasions, separated by 3 to 5 days. Forty-nine subjects were tested for within-day reliability. Forty-three subjects were reassessed for between-day reliability. Results: Intraclass correlation coefficients for within- and between-day assessment of scapular orientation during elevation and lowering of the arm in both groups ranged from 0.92 to 0.99 and from 0.54 to 0.88, respectively. Intraclass correlation coefficients for assessment of scapular orientation with the arms relaxed at the side in both groups ranged from 0.66 to 0.95. The standard error of measurement for between-day measurements ranged from 3.37° to 7.44° for both groups. The minimal detectable change for between-day measurements increased from 7.81° at the lower to 17.27° at the higher humerothoracic elevation angles. Conclusion: These results support the use of Flock of Birds to measure scapular orientations in subjects with and without impingement symptoms. The measurements showed excellent within-day reliability but were not highly reliable over time.
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Context: The literature does not present a consistent pattern of altered scapular kinematics in patients with shoulder-impingement syndrome (SIS). Objectives: To perform meta-analyses of published comparative studies to determine the consistent differences in scapular kinematics between subjects with SIS and controls. In addition, the purpose was to analyze factors of the data-collection methods to explain the inconsistencies in reported kinematics. The results of this study will help guide future research and enable our understanding of the relationship between scapular kinematics and SIS. Evidence acquisition: A search identified 65 studies; 9 papers met inclusion criteria. Sample sizes, means, and SDs of 5 scapular-kinematic variables were extracted or obtained from each paper's lead author. Standard difference in the mean between SIS and controls was calculated. Moderator variables were plane of arm elevation, level of arm elevation (ARM) and population (POP). Evidence synthesis: Overall, the SIS group had less scapular upward rotation (UR) and external rotation (ER) and greater clavicular elevation (ELE) and retraction (RET) but no differences in scapular posterior tilt (PT). In the frontal plane, SIS subjects showed greater PT and ER, and in the scapular plane, less UR and ER and greater ELE and RET. There was also greater ELE and RET in the sagittal plane. There was less UR at the low ARM and greater ELE and RET at the high ARM with SIS. Athletes and overhead workers showed less UR, while athletes showed greater PT and workers showed less PT and ER. The general population with SIS had greater ELE and RET only. Conclusions: Subjects with SIS demonstrated altered scapular kinematics, and these differences are influenced by the plane, ARM, and POP. Athletes and overhead workers have a different pattern of scapular kinematics than the general population. The scapular plane is most likely to demonstrate altered kinematics. These factors should be considered when designing futures studies to assess the impact of altered kinematics in patients with SIS.
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The purpose of this manuscript is to review the knowledge of scapular positioning at rest and scapular movement in different anatomic planes in asymptomatic subjects and patients with shoulder impingement syndrome (SIS) and glenohumeral shoulder instability. We reviewed the literature for all biomechanical and kinematic studies using keywords for impingement syndrome, shoulder instability, and scapular movement published in peer reviewed journal. Based on the predefined inclusion and exclusion criteria, 30 articles were selected for inclusion in the review. The literature is inconsistent regarding the scapular resting position. At rest, the scapula is positioned approximately horizontal, 35° of internal rotation and 10° anterior tilt. During shoulder elevation, most researchers agree that the scapula tilts posteriorly and rotates both upward and externally. It appears that during shoulder elevation, patients with SIS demonstrate a decreased upward scapular rotation, a decreased posterior tilt, and a decrease in external rotation. In patients with glenohumeral shoulder instability, a decreased scapular upward rotation and increased internal rotation is seen. This literature overview provides clinicians with insight into scapular kinematics in unimpaired shoulders and shoulders with impingement syndrome and instability.
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Observation of the scapular posture is one of the most important components of the physical examination in overhead athletes. Postural asymmetry is typically considered to be associated with injuries. However, asymmetry in the overhead athlete's scapula may be normal due to the dominant use of the limb. To quantify the differences in resting scapular posture between the dominant and nondominant sides in 3 groups of healthy overhead athletes (baseball pitchers, volleyball players, and tennis players) using an electromagnetic tracking device. Cross-sectional design. University-based biomechanics laboratory. A total of 43 players participated, including 15 baseball pitchers, 15 volleyball players, and 13 tennis players. All participants were healthy college-aged men. Bilateral 3-dimensional scapular kinematics with the arm at rest were measured using an electromagnetic tracking device. Bilateral scapular position and orientation were measured. Between-groups and between-sides differences in each variable were analyzed using separate analyses of variance. In tennis players, the scapula was more protracted on the dominant side than on the nondominant side (P < .05). In all overhead athletes, the dominant-side scapula was more internally rotated (P = .001) and anteriorly tilted (P = .001) than the nondominant-side scapula was. The dominant-side scapula of the overhead athletes was more internally rotated and anteriorly tilted than the nondominant-side scapula. The dominant-side scapula of the tennis players was more protracted than that on the nondominant side. Clinicians evaluating overhead athletes need to recognize that scapular posture asymmetry in unilateral overhead athletes may be normal. Our results emphasize the importance of the baseline evaluation in this population in order to accurately assess pathologic change in bilateral scapular positions and orientations after injury.
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This study examined the relationship between lower extremity dominance and kinematic symmetry during gait. Fourteen healthy volunteers without any observable gait deviations participated in the study. The subjects (8 male, 6 female) ranged in age from 19 to 56 years. Lower extremity lateral dominance was determined using an assessment method developed by Carol Coogler. Retroreflective spherical markers were placed bilaterally at points over the greater trochanter, the lateral joint line of the knee, the lateral malleolus, and the metatarsal break. A video-based data-acquisition instrument interfaced with a PDP 11/73 computer measured 12 kinematic variables while the subjects walked at self-selected speeds along a 10-m walkway. A multivariate analysis of variance with one repeated measure revealed significant differences between limbs, across subjects, for stance time and maximum knee extension. A within-subject analysis demonstrated significant differences for 10 variables; however, lateral dominance could not be related predictably to these variations. Our results indicate that symmetry cannot be generalized in view of intrasubject variability for these variables. [Valle DR, Gundersen LA, Barr AE, et al: Bilateral analysis of the knee and ankle during gait: An examination of the relationship between lateral dominance and symmetry.
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The purpose of this study was to propose a measure of symmetry/asymmetry for normal human gait and to quantify symmetries/asymmetries of normal human gait for selected gait variables using a force platform. Sixty-two subjects performed ten gait trials each, stepping on the force platform five times with each leg. From these gait trials a symmetry index was calculated for 34 gait variables. The upper and lower limits of normal gait were calculated such that 95% of all symmetry indices obtained from this subject population fell within these limits. Upper and lower limits were found to vary from +/- 4% to over +/- 13,000%. Extremely high percentages were found for variables which had absolute magnitudes close to zero and/or variables which occurred at distinctly different instants during the gait cycle. The results of these variables need to be interpreted with caution.
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Nonrandomized 2 group post-test only. To compare scapular position and orientation between subjects with and without impingement syndrome. Abnormal scapular motion is commonly believed to be a contributing factor to shoulder impingement syndrome. Twenty nonimpaired subjects with a mean age of 34.3 (+/- 7.5 years) and 17 patients with impingement syndrome with a mean age of 45.8 (+/- 11.0) participated. A 3-dimensional electromechanical digitizer was used to measure scapular position and orientation in 3 planes. Measurements were taken with the arm at the side, elevated in the scapular plane to horizontal, and at maximum elevation. One-way analysis of variance was used to compare nonimpaired subjects to the impingement group and the symptomatic and asymptomatic sides within the impingement group. Five scapular kinematic variables were assessed at each arm position. Orientation was described by posterior tilting angle, upward rotation angle, and internal rotation angle. Position was described by medial-lateral position and superior-inferior position and determined by the distance from the scapula centroid to the seventh cervical vertebra (C7). During scapular plane elevation of the arm, the scapula showed a general pattern of increasing posterior-tilt angle, increasing upward-rotation angle, and decreasing internal-rotation angle in both impingement and nonimpaired groups. Also, the scapula moved to a more superior position and a slightly more medial position with increasing arm elevation. Compared to nonimpaired subjects (34.6 degrees +/- 9.7), those with impingement demonstrated a significantly lower posterior tilting angle of the scapula in the sagittal plane (25.1 degrees +/- 9.1). Subjects with impingement also demonstrated higher superior-inferior scapular position with maximal arm elevation (5.2 cm +/- 1.6 below the first thoracic vertebrae) compared to nonimpaired subjects (7.5 cm +/- 1.5). These results suggest that altered scapular kinematics may be an important aspect of the impingement syndrome.
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The validation of two noninvasive methods for measuring the dynamic three-dimensional kinematics of the human scapula with a magnetic tracking device is presented. One method consists of simply fixing a sensor directly to the acromion and the other consists of mounting a sensor to an adjustable plastic jig that fits over the scapular spine and acromion. The concurrent validity of both methods was assessed separately by comparison with data collected simultaneously from an invasive approach in which pins were drilled directly into the scapula. The differences between bone and skin based measurements represents an estimation of skin motion artifact. The average motion pattern of each surface method was similar to that measured by the invasive technique, especially below 120 degrees of elevation. These results indicate that with careful consideration, both methods may offer reasonably accurate representations of scapular motion that may be used to study shoulder pathologies and help develop computational models.
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Measurement of scapular kinematics is an important component in the assessment of shoulder function; however, repeatability of these measurements has not been established. The purpose of this study, therefore, was to determine the repeatability of scapular rotation measures for different humeral elevation planes between trials, sessions, and days. Three-dimensional scapular rotations were collected using an electromagnetic tracking system in three planes of humeral elevation. Coefficient of multiple correlation (CMC) values were calculated between trials, sessions, and days for curves of scapular rotations. CMC values were compared with repeated measures analysis of variance (ANOVAs) and Tukey's post-hoc procedures. Tests of simple main effects were performed for significant interaction effects. Our results suggest that scapular rotation measures are repeatable between trials within the same testing session, but less repeatable between testing sessions and days. Sagittal plane elevation consistently yielded the highest CMC values for all scapular rotations. These results suggest sagittal plane elevation should be considered to evaluate differences in scapular rotations.
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Several factors such as posture, muscle force, range of motion, and scapular dysfunction are commonly believed to contribute to shoulder impingement. The purpose of this study was to compare 3-dimensional scapular kinematics, shoulder range of motion, shoulder muscle force, and posture in subjects with and without primary shoulder impingement syndrome. Forty-five subjects with impingement syndrome were recruited and compared with 45 subjects without known pathology or impairments matched by age, sex, and hand dominance. Shoulder motion and thoracic spine posture were measured goniometrically, and force was measured with a dynamometer. An electromagnetic motion analysis system was used to capture shoulder kinematics during active elevation in both the sagittal and scapular planes as well as during external rotation with the arm at 90 degrees of elevation in the frontal plane. The impingement group demonstrated slightly greater scapular upward rotation and clavicular elevation during flexion and slightly greater scapular posterior tilt and clavicular retraction during scapular-plane elevation compared with the control group. The impingement group demonstrated less range of motion and force in all directions compared with the control group. There were no differences in resting posture between the groups. The kinematic differences found in subjects with impingement may represent scapulothoracic compensatory strategies for glenohumeral weakness or motion loss. The decreased range of motion and force found in subjects with impingement support rehabilitation approaches that focus on strengthening and restoring flexibility.
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Overhead athletes require a delicate balance of shoulder mobility and stability in order to meet the functional demands of their respective sport. Altered shoulder mobility has been reported in overhead athletes and is thought to develop secondary to adaptive structural changes to the joint resulting from the extreme physiological demands of overhead activity. Researchers have speculated as to whether these structural adaptations compromise shoulder stability, thus exposing the overhead athlete to shoulder injury. Debate continues as to whether these altered mobility patterns arise from soft-tissue or osseous adaptations within and around the shoulder. Researchers have used quantitative techniques in an attempt to better characterize these structural adaptations in the shoulders of overhead athletes. Throwing athletes have been shown to display altered rotational range of motion (ROM) patterns in the dominant shoulder that favour increased external rotation and limited internal rotation ROM. Throwers also show a loss of horizontal or cross-body adduction in the throwing shoulder when compared with the non-throwing shoulder. This posterior shoulder immobility in the throwing shoulder is thought by some researchers to be associated with reactive scarring or contracture of the periscapular soft-tissue structures (e.g. posterior capsule and/or cuff musculature); however, evidence of reactive scarring or contractures of the posterior-inferior capsule or cuff musculature from anatomic or noninvasive imaging studies is lacking. Conversely, translational ROM (laxity) has been consistently shown to be symmetric between dominant and non-dominant shoulders of overhead athletes. From a skeletal perspective, throwing shoulders are shown to have more humeral retroversion when compared with the non-throwing shoulder. Alterations in humeral retroversion are thought to develop over time in young pre-adolescent throwers when the proximal humeral epiphysis is not yet completely fused. Even though the evidence is inconclusive at the present time, there is more compelling evidence that leads us to believe that altered shoulder mobility in the overhead-throwing athlete is more strongly associated with adaptive changes in proximal humeral anatomy (i.e. retroversion) than to structural changes in the articular and periarticular soft tissue structures. In addition, this retroversion is thought to account for the observed shift in the arc of rotational ROM in overhead athletes. However, in some athletes, capsulo-ligamentous adaptations such as anterior-inferior stretching or posterior-inferior contracture may become superimposed upon the osseous changes. This may ultimately lead to pathological manifestations such as secondary impingement, type II superior labrum from anterior to posterior (SLAP) lesions and/or internal (glenoid) impingement. Overuse injuries in the overhead athlete are a common and perplexing clinical problem in sports medicine and, therefore, it is imperative for sports medicine clinicians to have a thorough understanding of the short- and long-term effects of overhead activity on the shoulder complex. It is our intention that the information presented will serve as a guide for clinicians who treat the shoulders of overhead athletes.
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There is a growing body of literature associating abnormal scapular positions and motions, and, to a lesser degree, clavicular kinematics with a variety of shoulder pathologies. The purpose of this manuscript is to (1) review the normal kinematics of the scapula and clavicle during arm elevation, (2) review the evidence for abnormal scapular and clavicular kinematics in glenohumeral joint pathologies, (3) review potential biomechanical implications and mechanisms of these kinematic alterations, and (4) relate these biomechanical factors to considerations in the patient management process for these disorders. There is evidence of scapular kinematic alterations associated with shoulder impingement, rotator cuff tendinopathy, rotator cuff tears, glenohumeral instability, adhesive capsulitis, and stiff shoulders. There is also evidence for altered muscle activation in these patient populations, particularly, reduced serratus anterior and increased upper trapezius activation. Scapular kinematic alterations similar to those found in patient populations have been identified in subjects with a short rest length of the pectoralis minor, tight soft-tissue structures in the posterior shoulder region, excessive thoracic kyphosis, or with flexed thoracic postures. This suggests that attention to these factors is warranted in the clinical evaluation and treatment of these patients. The available evidence in clinical trials supports the use of therapeutic exercise in rehabilitating these patients, while further gains in effectiveness should continue to be pursued.
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Using the spark plasma sintering (SPS) process, Al4SiC4 powder was synthesized at a temperature 550 °C lower and for one-sixth of the holding time compared with the conventional heating method. The extrusion of molten raw powder and the temperature overshoot could be prevented by modifying the mold. The increase in maximum applicable temperature for powder synthesis was another benefit of the new mold. The synthesis temperature and time decreased with increasing size of the mold as a result of the effect of high current during SPS.
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Generally, the scapular motions of pathologic and contralateral normal shoulders are compared to characterize shoulder disorders. However, the symmetry of scapular motion of normal shoulders remains undetermined. Therefore, the aim of this study was to compare 3dimensinal (3D) scapular motion between dominant and nondominant shoulders during three different planes of arm motion by using an optical tracking system. Twenty healthy subjects completed five repetitions of elevation and lowering in sagittal plane flexion, scapular plane abduction, and coronal plane abduction. The 3D scapular motion was measured using an optical tracking system, after minimizing reflective marker skin slippage using ultrasonography. The dynamic 3D motion of the scapula of dominant and nondominant shoulders, and the scapulohumeral rhythm (SHR) were analyzed at each 10° increment during the three planes of arm motion. There was no significant difference in upward rotation or internal rotation (P > 0.05) of the scapula between dominant and nondominant shoulders during the three planes of arm motion. However, there was a significant difference in posterior tilting (P = 0.018) during coronal plane abduction. The SHR was a large positive or negative number in the initial phase of sagittal plane flexion and scapular plane abduction. However, the SHR was a small positive or negative number in the initial phase of coronal plane abduction. Only posterior tilting of the scapula during coronal plane abduction was asymmetrical in our healthy subjects, and depending on the plane of arm motion, the pattern of the SHR differed as well. These differences should be considered in the clinical assessment of shoulder pathology.
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Controlled laboratory study. To measure superior/inferior translation and external rotation of the humerus relative to the scapula during scapular plane abduction using 3-D/2-D model image registration techniques. Kinematic changes in the glenohumeral joint, including excessive superior translation of the humeral head and inadequate external rotation of the humerus, are believed to be a possible cause of shoulder impingement. Although many researchers have analyzed glenohumeral kinematics with various methods, few articles have assessed dynamic in vivo glenohumeral motion. Twelve healthy males with a mean age of 32 years (range, 27-36 years) were enrolled in this study. Fluoroscopic images of the dominant shoulder during scapular plane elevation were taken, and computed tomography-derived 3-D bone models were matched with the silhouette of the bones in the fluoroscopic images using 3-D/2-D model image registration techniques. The kinematics of the humerus relative to the scapula were determined using Euler angles. On average, there was 2.1 mm of initial humeral translation in the superior direction from the starting position to 105° of humeral elevation. Subsequently, an average of 0.9 mm of translation in the inferior direction occurred between 105° and maximum arm elevation. The average amount of external rotation of the humerus was 14° from the starting position to 60° of humeral elevation. The humerus then rotated internally an average 9° by the time the shoulder reached maximum elevation. These changes in superior/inferior translation and external/internal rotation were statistically significant (P<.001 and P = .001, respectively), based on 1-way repeated-measures analysis of variance. The observed glenohumeral translations and rotations characterize healthy shoulder function and serve as a preliminary foundation for quantifying pathomechanics in the presence of glenohumeral joint disorders.
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The exact role and the function of the scapula are misunderstood in many clinical situations. This lack of awareness often translates into incomplete evaluation and diagnosis of shoulder problems. In addition, scapular rehabilitation is often ignored. Recent research, however, has demonstrated a pivotal role for the scapula in shoulder function, shoulder injury, and shoulder rehabilitation. This knowledge will help the physician to provide more comprehensive care for the athlete. This "Current Concepts" review will address the anatomy of the scapula, the roles that the scapula plays in overhead throwing and serving activities, the normal biomechanics of the scapula, abnormal biomechanics and physiology of the scapula, how the scapula may function in injuries that occur around the shoulder, and treatment and rehabilitation of scapular problems.
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Alterations in scapular motion frequently are seen in association with various shoulder disorders. It is common clinically to compare the pathological shoulder with the contralateral shoulder, in spite of arm dominance, to characterize the disorder. However, there have been few articles that test the underlying assumption that dominant and nondominant shoulders exhibit comparable dynamic kinematics. The purpose of this study was to compare the 3-dimensional (3-D) scapular kinematics of dominant and nondominant shoulders during dynamic scapular plane elevation using 3-D-2-D (2-dimensional) registration techniques. Twelve healthy males with a mean age of 32 years (range, 27-36) were enrolled in this study. Bilateral fluoroscopic images during scapular plane elevation and lowering were taken, and CT-derived 3-D bone models were matched with the silhouette of the bones in the fluoroscopic images using 3-D-2-D registration techniques. Angular values of the scapula and scapulohumeral rhythm were compared between dominant and nondominant shoulders with statistical analysis. There was a significant difference in upward rotation angles between paired shoulders (P < .001), while significant differences were not found in the other angular values and scapulohumeral rhythm. The dominant scapulae were 10° more downwardly rotated at rest and 4° more upwardly rotated during elevation compared to the nondominant scapulae. Scapular motion was not the same between dominant and nondominant arms in healthy subjects. The dominant scapula was rotated further downward at rest and reached greater upward rotation with abduction. These differences should be considered in clinical assessment of shoulder pathology.
Article
Background and Purpose. Treatment of patients with impingement symptoms commonly includes exercises intended to restore “normal” movement patterns. Evidence that indicates the existence of abnormal patterns in people with shoulder pain is limited. The purpose of this investigation was to analyze glenohumeral and scapulothoracic kinematics and associated scapulothoracic muscle activity in a group of subjects with symptoms of shoulder impingement relative to a group of subjects without symptoms of shoulder impingement matched for occupational exposure to overhead work. Subjects. Fifty-two subjects were recruited from a population of construction workers with routine exposure to overhead work. Methods. Surface electromyographic data were collected from the upper and lower parts of the trapezius muscle and from the serratus anterior muscle. Electromagnetic sensors simultaneously tracked 3-dimensional motion of the trunk, scapula, and humerus during humeral elevation in the scapular plane in 3 hand-held load conditions: (1) no load, (2) 2.3-kg load, and (3) 4.6-kg load. An analysis of variance model was used to test for group and load effects for 3 phases of motion (31°–60°, 61°–90°, and 91°–120°). Results. Relative to the group without impingement, the group with impingement showed decreased scapular upward rotation at the end of the first of the 3 phases of interest, increased anterior tipping at the end of the third phase of interest, and increased scapular medial rotation under the load conditions. At the same time, upper and lower trapezius muscle electromyographic activity increased in the group with impingement as compared with the group without impingement in the final 2 phases, although the upper trapezius muscle changes were apparent only during the 4.6-kg load condition. The serratus anterior muscle demonstrated decreased activity in the group with impingement across all loads and phases. Conclusion and Discussion. Scapular tipping (rotation about a medial to lateral axis) and serratus anterior muscle function are important to consider in the rehabilitation of patients with symptoms of shoulder impingement related to occupational exposure to overhead work.
Article
The purposes of this study were to (1) assess the inter-rater reliability and validity of 2 clinical assessment methods of categorizing scapular dyskinesis and (2) quantify the frequency of asymmetry of bilateral scapular motion in injured and uninjured shoulders by use of 3-dimensional (3D) kinematic analysis. We evaluated 56 subjects, 35 with shoulder injury and 21 with no symptoms. Two blinded evaluators categorized the scapular motion of all subjects to determine inter-rater reliability using 2 observational methods ("yes/no" and "4 type") to evaluate scapular dyskinesis. Subjects were also instrumented with electromagnetic receivers to assess bilateral 3D scapular kinematics to determine the presence of dyskinesis and establish criterion validity of the 2 methods. The inter-rater percent agreement and the degree of this agreement as measured by kappa statistic showed that the yes/no method produced a higher inter-rater percent agreement (79%, kappa = 0.40) than the 4-type method (61%, kappa = 0.44). The yes/no method had a higher sensitivity (76%) and positive predictive value (74%) when compared with the 3D criterion. A chi(2) analysis found significantly more multiple-plane asymmetries in symptomatic subjects (54%) in flexion compared with asymptomatic subjects (14%) (P = .002). The yes/no method allows multiple-plane asymmetries to be considered in clinical assessment and therefore renders this a good screening tool for the presence of scapular dyskinesis. Kinematic analysis shows that asymmetries are common in symptomatic and asymptomatic populations. Testing in flexion showed a higher frequency of multiple-plane scapular asymmetries in the symptomatic group. Identification of scapular dyskinesis is a key component of the shoulder examination. The clinician's ability to establish the presence or absence of scapular dyskinesis by observation is enhanced using a simple yes/no method especially when testing subjects in shoulder forward flexion. Although scapular asymmetries appear to be a prevalent finding, dyskinesis in the presence of shoulder symptoms should be considered a potential factor contributing to the dysfunction in the presence of shoulder symptoms should be considered a potential factor contributing to the dysfunction.
Article
Assessment of whether elevation and lowering of the dominant and nondominant arms occur in a similar manner in healthy individuals is clinically important in terms of shoulder disorders. We examined the scapulohumeral rhythm (SHR) and performed electromyography (EMG) for the middle deltoid, upper trapezius, lower trapezius, and lower part of the serratus anterior muscles of both shoulders in 18 healthy volunteers (14 men, 4 women) with a mean age of 24 years (range, 19-30 years). The participants randomly elevated and lowered either the right or left arm in the scapular plane, and the motion was measured using a 3-dimensional motion analyzer. The average angles of maximum arm elevation and scapular upward rotation were 130.3 degrees +/- 7.9 degrees and 32.2 degrees +/- 5.6 degrees, respectively, for dominant arms, and 130.8 degrees +/- 6.4 degrees and 31.8 degrees +/- 5.8 degrees, respectively, for nondominant arms. The SHR in each 10 degrees increment did not differ significantly between the dominant and nondominant arms in each participant during elevation (P = .337) and lowering (P = .1). A significant difference was found in the percentage integrated EMG (%IEMG) of the lower trapezius between the 2 shoulders (P < .049). If the kinematic difference is identified between both shoulders, we can predict the dysfunction or disorder in shoulder complex. Moreover, we should evaluate how shoulder muscles are used and whether the muscle becomes weak. Healthy individuals elevate and lower the dominant and nondominant shoulders in a similar kinematical pattern despite 3 of 4 muscles indicating different EMG activities between both shoulders.
Article
Unlabelled: There is a growing body of literature associating abnormal scapular positions and motions, and, to a lesser degree, clavicular kinematics with a variety of shoulder pathologies. The purpose of this manuscript is to (1) review the normal kinematics of the scapula and clavicle during arm elevation, (2) review the evidence for abnormal scapular and clavicular kinematics in glenohumeral joint pathologies, (3) review potential biomechanical implications and mechanisms of these kinematic alterations, and (4) relate these biomechanical factors to considerations in the patient management process for these disorders. There is evidence of scapular kinematic alterations associated with shoulder impingement, rotator cuff tendinopathy, rotator cuff tears, glenohumeral instability, adhesive capsulitis, and stiff shoulders. There is also evidence for altered muscle activation in these patient populations, particularly, reduced serratus anterior and increased upper trapezius activation. Scapular kinematic alterations similar to those found in patient populations have been identified in subjects with a short rest length of the pectoralis minor, tight soft-tissue structures in the posterior shoulder region, excessive thoracic kyphosis, or with flexed thoracic postures. This suggests that attention to these factors is warranted in the clinical evaluation and treatment of these patients. The available evidence in clinical trials supports the use of therapeutic exercise in rehabilitating these patients, while further gains in effectiveness should continue to be pursued. Level of evidence: Level 5.
Article
Qualitative visual inspection and manual muscle testing are traditional methods of evaluation that may overlook subtle weakness of the axioscapular musculature. A modification of the standard technique of Moiré topographic analysis of spinal deformity was applied to assess axioscapular muscle function in 51 subjects: 22 asymptomatic individuals, 22 with shoulder instability, and seven with impingement syndrome. Static Moiré evaluation demonstrated scapulothoracic asymmetry or increased topography in 14% of asymptomatic subjects, compared with 32% and 57% in the instability and impingement groups, respectively. The dynamic Moiré test demonstrated an abnormal Moiré pattern in 18% of asymptomatic individuals, compared with 64% and 100% in the instability and impingement groups, respectively. Axioscapular muscle dysfunction is common with both instability and impingement syndrome of the shoulder, although it remains to be determined whether this represents a primary or secondary phenomenon.
Article
The purpose of this investigation was to determine whether force platform measurements can be used to objectively assess short-term effects of spinal manipulation on patients with diagnosed, chronic unilateral "sacroiliac dyskinesia," here defined as decreased interarticular mobility of the sacroiliac joint. Nine patients walked across a force platform, were than manipulated by a chiropractor and then repeated the gait trials. Temporal and kinetic gait variables from the force platform measurements were analyzed for changes in the symmetry of the subjects' gait before and after treatment sessions. There was a distinct tendency towards improved gait symmetry after treatment in those cases where the gait was asymmetric prior to the treatment. This result indicated that force platform measurements may be used successfully to assess the effects of spinal manipulations on the gait of patients with sacroiliac dyskinesia.
Article
Impingement lesions are considered in three progressive stages: I, edema and hemorrhage; II, fibrosis and tendinitis; III, tears of the rotator cuff, biceps ruptures, and bone changes. The physical findings in all of these stages are similar, accounting for some of the misconceptions about tears of the rotator cuff. The 'impingement test' identifies these lesions. Arthrography is the most reliable method of identifying complete-thickness tears from other impingement lesions. Further observations confirm that impingement occurs anteriorly, not laterally. It is thought that most supraspinatus and biceps lesions are due to impingement wear, usually caused in part by variations in the shape and slope of the acromion. When these tendons rupture, impingement may be escalated, because the head is allowed to migrate upward. Anterior acromioplasty is used routinely when tears of the rotator cuff are repaired, to decompress the supraspinatus from continuing wear. It is also used for chronic disability associated with incomplete tears but only occasionally in patients younger than 40 years of age. The approach offered by an anterior acromioplasty for repairing the rotator cuff offers three advantages over lateral acromionectomy: (1) less deltoid detachment; (2) better exposure of the supraspinatus; and (3) better decompression of the supraspinatus against continuing impingement. Small, unfused anterior acromial epiphyses are excised, whereas larger, unfused centers are tilted up and closed by curettage and local bone grafts, and internally fixed with screws or threaded wires.
Article
Athletes, particularly those who are involved in sporting activities requiring repetitive overhead use of the arm (for example, tennis players, swimmers, baseball pitchers, and quarterbacks), may develop a painful shoulder. This is often due to impingement in the vulnerable avascular region of the supraspinatus and biceps tendons. With the passage of time, degeneration and tears of the rotator cuff may result. Pathologically the syndrome has been classified into Stage I (edema and hemorrhage), Stage II (fibrosis and tendonitis), and Stage III (tendon degeneration, bony changes, and tendon ruptures). The impingement syndrome may be a problem for the young, active, and competitive athlete as well as the casual weekend athlete. The "impingement sign" which reproduces pain and resulting facial expression when the arm is forceably forward flexed (jamming the greater tuberosity against the anteroinferior surface of the acromion) is the most reliable physical sign in establishing the diagnosis. Flexibility exercises, strengthening programs, and special training techniques are a preventive and treatment requirement. Rest and local modalities such as ice, ultrasound, and antiinflammatory agents are usually effective to lessen the inflammatory reaction. Surgical decompression by resecting the coracoacromial ligament or a more definitive anterior acromioplasty may rarely be indicated.
Article
Athletes with shoulder pathology consistently demonstrate abnormalities in scapular rotator activity, suggesting that muscle dysfunction is a factor to consider in the aetiology or recurrence of shoulder pain. However, one important measure of the coordinated activity between the scapular rotators, their timing or temporal recruitment pattern, remains undetermined. The purposes of this study were to 1. provide normative data on the temporal recruitment pattern of the scapular rotators in freestyle swimmers, 2. determine the effect of a unilateral shoulder injury on this pattern, 3. determine whether these effects extend to the non-injured side, and 4. determine the effect of injury on the consistency (variability) of muscle recruitment. Surface EMG data for the upper and lower trapezius and serratus anterior were recorded bilaterally from two groups of competitive freestyle swimmers during controlled bilateral elevation in the plane of the scapula. An injured group comprising nine swimmers with unilateral shoulder pathology and a control group of nine non-injured swimmers were included. Temporal data determined for the onset of muscle activation for each muscle were then compared between groups using an ANOVA and a one-sided F test. The results of the study indicate that in non-injured swimmers, upper trapezius is activated 217 ms prior to shoulder motion, followed by serratus anterior activation 53 ms after motion commences. Lower trapezius was not recruited until 349 ms after shoulder motion, when the arm had attained 15 degrees elevation. In injured swimmers, all three muscles on the injured side displayed significantly increased variability in the timing of activation (p < 0.05), whilst the serratus anterior was significantly delayed in its activation on the non-injured side (p < 0.05). Skill hand preference was shown to have no effect on muscle recruitment. The findings of this study indicate that a relationship does exist between shoulder injury and the temporal recruitment patterns of the scapular rotators, such that injury reduces the consistency of muscle recruitment. They further suggest that injured subjects have muscle function deficits on their unaffected side.
Article
In this paper, a method is described for in vivo prediction of the glenohumeral joint rotation center (GH-r), necessary for the construction of a humerus local coordinate system in shoulder kinematic studies. The three-dimensional positions of five scapula bony landmarks as well as a large number of data points on the surface of the glenoid and humeral head were collected at 36 sets of cadaver scapulae and adjacent humeri. The position of GH-r in each scapula was estimated by mathematically fitting spheres to the glenoid and humeral head. GH-r prediction from scapula geometry parameters by linear regression resulted in a RMSE between measured and predicted GH-r of 2.32 mm for the x-coordinate, 2.69 mm for the y-coordinate and 3.04 mm for the z-coordinate. Application in vivo revealed a random humerus orientation error due to measurement inaccuracies of 1.35, 0.29 and 1.26 degrees standard deviation per rotation angle. The estimated total humerus orientation error including the offset error due to the regression model inaccuracy was 2.86, 0.84 and 2.69 degrees standard deviation. As these errors were about 15 and 20% of, respectively, the intra- and inter-subject variability of the humerus orientations measured, it is concluded that the method described in this paper allows for an adequate construction of a humerus local coordinate system.
Article
The relationship between repetitive motion and subacromial impingement and rotator cuff disease is controversial and poorly understood. The potential etiology is multifactorial and involves patient related factors (age, supraspinatus outlet anatomy, and preexisting rotator cuff pathology) and worker related factors (arm position, lifting requirements, numbers of repetitions). Radiographic and magnetic resonance imaging abnormalities may represent preexisting disease that could have predisposed the patient to the development of impingement syndrome, but should be interpreted cautiously within the context of the remainder of the clinical picture. Treatment often involves temporary or permanent modifications of the work environment.
Article
To compare trunk muscle coordination in people with and without low back pain with varying speeds of limb movement. Abdominal and back extensor muscle activity in association with upper limb movement was compared among three speeds of movement and between people with and without low back pain. Fourteen subjects with a history of recurrent low back pain and a group of age- and sex-matched control subjects. The onsets of electromyographic activity of the trunk and limb muscles, frequency of trunk muscle responses, and angular velocity of arm movements. Early activation of transversus abdominis (TrA) and obliquus internus abdominis (OI) occurred in the majority of trials, with movement at both the fast and intermediate speeds for the control group. In contrast, subjects with low back pain failed to recruit TrA or OI in advance of limb movement with fast movement, and no activity of the abdominal muscles was recorded in the majority of intermediate speed trials. There was no difference between groups for slow movement. The results indicate that the mechanism of preparatory spinal control is altered in people with lower back pain for movement at a variety of speeds.
Article
Treatment of patients with impingement symptoms commonly includes exercises intended to restore "normal" movement patterns. Evidence that indicates the existence of abnormal patterns in people with shoulder pain is limited. The purpose of this investigation was to analyze glenohumeral and scapulothoracic kinematics and associated scapulothoracic muscle activity in a group of subjects with symptoms of shoulder impingement relative to a group of subjects without symptoms of shoulder impingement matched for occupational exposure to overhead work. Fifty-two subjects were recruited from a population of construction workers with routine exposure to overhead work. Surface electromyographic data were collected from the upper and lower parts of the trapezius muscle and from the serratus anterior muscle. Electromagnetic sensors simultaneously tracked 3-dimensional motion of the trunk, scapula, and humerus during humeral elevation in the scapular plane in 3 handheld load conditions: (1) no load, (2) 2. 3-kg load, and (3) 4.6-kg load. An analysis of variance model was used to test for group and load effects for 3 phases of motion (31(-60(, 61(-90(, and 91(-120(). Relative to the group without impingement, the group with impingement showed decreased scapular upward rotation at the end of the first of the 3 phases of interest, increased anterior tipping at the end of the third phase of interest, and increased scapular medial rotation under the load conditions. At the same time, upper and lower trapezius muscle electromyographic activity increased in the group with impingement as compared with the group without impingement in the final 2 phases, although the upper trapezius muscle changes were apparent only during the 4.6-kg load condition. The serratus anterior muscle demonstrated decreased activity in the group with impingement across all loads and phases. Scapular tipping (rotation about a medial to lateral axis) and serratus anterior muscle function are important to consider in the rehabilitation of patients with symptoms of shoulder impingement related to occupational exposure to overhead work. [Ludewig PM, Cook TM. Alterations in shoulder kinematics and associated muscle activity in people with symptoms of shoulder impingement.
Article
This study presents an objective evaluation of both scapular upward and axial rotational tilts in shoulder impingement syndrome, using a scapular spine line defined on antero-posterior (AP) radiographs of the shoulder as the referential line. Twenty-seven patients with unilateral shoulder motion pain, who were diagnosed as having chronic shoulder impingement syndrome, were enrolled in the study. Scapular upward and axial rotational tilts were compared between the affected and contralateral shoulders. AP radiographs were obtained at shoulder abduction angles of 0 degrees, 45 degrees, and 90 degrees, and the X-ray films were digitized by computer. The upward and axial rotational tilts of the scapula were then evaluated on the digital images. In shoulder impingement syndrome, both upward and axial external rotations of the scapula were impaired at the painful arc angle of abduction. This tended to be more apparent for the axial rotation of the scapula than for the upward rotation. These reductions in scapular rotations reduce available clearance for the rotator cuff and humeral greater tuberosity as the shoulder is abducted.
Article
To quantify the contribution of each scapular rotation to the scapular total range of motion (ROM) in both shoulders of persons with a unilateral shoulder impingement syndrome (SIS), to compare 3-dimensional (3D) scapular attitudes of their symptomatic and asymptomatic shoulders in flexion and in abduction, and to characterize the scapular behavior of these subjects by classifying them into subgroups based on scapular tilting differences between their symptomatic and asymptomatic shoulders. Comparisons of 3D scapular attitudes, scapular total ROM, and percentage of contributions of each scapular rotation to the scapular total ROM. A motricity laboratory. Fifty-one subjects, including 41 with a SIS (29 had an asymptomatic contralateral shoulder) and 10 healthy subjects. The 3D scapular attitudes were calculated with the subjects in a standardized seated position; with the arm at rest; or at 70 degrees, 90 degrees, and 110 degrees of shoulder flexion and abduction. Axial rotation angles were calculated using a fixed set of Cardanic angles. At 90 degrees of arm elevation, data from 10 shoulders of healthy subjects were used to set up normative values (99% confidence interval of mean 3D scapular attitudes) to compare with 3D scapular attitudes of symptomatic and asymptomatic shoulders of SIS subjects. We analyzed the scapula behavior of subjects with SIS and classified them into subgroups based on scapular anterior tilting asymmetry. In flexion, almost half of the scapular total ROM was provided by anterior tilting (48.2%-51.3%), whereas in abduction, external rotation (40.3%-42.4%) was the main contributor. Scapular total ROM was higher in abduction than in flexion in all arm positions for both shoulder groups (P <.01). Also, 3D scapular attitude patterns of both shoulders of SIS subjects were different from those of healthy subjects. At 90 degrees, scapular asymmetry in anterior tilting allowed us to classify SIS subjects with respect to more (lead) or less (lag) scapular tilting in the affected side (P <.0001) or no difference (P =.11) between the sides (symmetrical). No significant differences (P >.05), except for a small 2 degrees difference in transverse rotation during arm flexion at 110 degrees (P =.002), were observed in 3D scapular attitudes and scapular total ROM between both shoulders of SIS subjects. Patterns of 3D scapular attitudes and scapular total ROM were significantly different between flexion and abduction arm positions (P <.05). The contribution of rotations and scapular total ROM differed according to the plane of arm elevation in SIS subjects. Group analyses revealed no differences in 3D scapular attitudes between symptomatic and asymptomatic shoulders of subjects with unilateral SIS. This could be caused by the use, in SIS subjects, of inappropriate neuromuscular strategies affecting both shoulders. However, individual analyses revealed scapular asymmetry in the sagittal plane, which suggests that SIS subjects with less anterior tilting in the symptomatic shoulder, as compared with the asymptomatic contralateral one, may be at high risk of developing chronic SIS. This last finding provides scientific evidence to focus rehabilitation protocols toward a restoration of anterior tilting.
Article
Accurate noninvasive clinical tests of shoulder instability are important in assessing and planning treatment for glenohumeral joint instability. An interexaminer agreement trial was undertaken to estimate the reliability of commonly used clinical tests for shoulder instability. Thirteen patients with a history suggestive of instability, who had been referred to a shoulder specialist for treatment of their symptomatic shoulders, were examined by four examiners of differing experience. Good to excellent interexaminer agreement was found for most variations of the load-and-shift test, with the best agreement in the 90 degrees abducted position for the anterior direction (intraclass correlation coefficient [ICC] = 0.72) and in the 0 degrees abducted position for the posterior (ICC = 0.68) and inferior (ICC = 0.79) directions. Fair to good interexaminer reliability was found for the sulcus sign (ICC = 0.60). With regard to the provocative tests, agreement was best when apprehension was used as the criterion for a positive test and was better for the relocation (ICC = 0.71) and release tests (ICC = 0.63) than for the apprehension (ICC = 0.47) and augmentations tests (ICC = 0.48). Reliability was poor (ICC < 0.31) when pain was used as the criterion for a positive test. These results indicate that the load-and-shift, sulcus, and provocative tests (apprehension, augmentation, relocation, and release) are reliable clinical tests for instability in symptomatic patients when care is taken with respect to arm positioning and if apprehension is used as the criterion for a positive provocative test.
Article
The objective of this study was to compare onset of deep and superficial cervical flexor muscle activity during rapid, unilateral arm movements between ten patients with chronic neck pain and 12 control subjects. Deep cervical flexor (DCF) electromyographic activity (EMG) was recorded with custom electrodes inserted via the nose and fixed by suction to the posterior mucosa of the oropharynx. Surface electrodes were placed over the sternocleidomastoid (SCM) and anterior scalene (AS) muscles. While standing, subjects flexed and extended the right arm in response to a visual stimulus. For the control group, activation of DCF, SCM and AS muscles occurred less than 50 ms after the onset of deltoid activity, which is consistent with feedforward control of the neck during arm flexion and extension. When subjects with a history of neck pain flexed the arm, the onsets of DCF and contralateral SCM and AS muscles were significantly delayed ( p<0.05). It is concluded that the delay in neck muscle activity associated with movement of the arm in patients with neck pain indicates a significant deficit in the automatic feedforward control of the cervical spine. As the deep cervical muscles are fundamentally important for support of the cervical lordosis and the cervical joints, change in the feedforward response may leave the cervical spine vulnerable to reactive forces from arm movement.
Article
Scapular activity during shoulder motion is critical for normal shoulder function. With aging, muscle function deteriorates in almost all people, which may lead to shoulder impingement syndrome. Forty-four normal subjects, 23 men and 21 women aged from 16 to 73 years with a mean age 48, were enrolled in the study. Static antero-posterior radiography at both 0 degrees and 90 degrees of abduction were undertaken and correlation between age and scapular orientations were evaluated by Pearson's correlation coefficient test. The purpose of this study is to investigate the relationship between aging and scapulo-thoracic orientation. Significant correlation coefficients were observed between aging and scapular orientations. With the shoulder at 0 degrees abduction, posterior tilt showed significant negative correlation with aging. At 90 degrees abduction, both posterior tilt and upward rotation angle correlated negatively with aging. The correlation was apparent at 90 degrees abduction. The results indicate that shoulder aging closely relates to changes of scapular orientation, which consist of decreases of the posterior tilt at 0 degrees and 90 degrees abduction and the upward rotation angle at 90 degrees. The current study indicated that one of the effects of aging on the shoulder is a decrease of posterior tilt and upward rotation angle as seen in an abducted position; and that these alterations are similar to the scapular kinematics of shoulder impingement syndrome. By taking this concept into consideration, the effects of aging on shoulder kinematics can be appropriately evaluated.
Article
In this communication, the Standardization and Terminology Committee (STC) of the International Society of Biomechanics proposes a definition of a joint coordinate system (JCS) for the shoulder, elbow, wrist, and hand. For each joint, a standard for the local axis system in each articulating segment or bone is generated. These axes then standardize the JCS. The STC is publishing these recommendations so as to encourage their use, to stimulate feedback and discussion, and to facilitate further revisions. Adopting these standards will lead to better communication among researchers and clinicians.
Article
Quantification of asymmetry is a common objective in both research and clinical settings. The most common method for quantification of asymmetry of discrete variables is calculation of the symmetry index. Essentially a measure of the percent difference between sides, the symmetry index requires the choice of a reference value. This is a limitation as the choice of value is not always clear, and can lead to inconsistent results and artificially inflated values. Therefore, the purposes of the current study were to examine the limitations of the symmetry index in depth, define a new method of quantifying symmetry that is robust to those limitations (the symmetry angle), and compute the correlations between the two measures. The results showed that, when using the symmetry index, the interpretation of asymmetry can be highly affected by the choice of reference value. The symmetry angle does not require the choice of a reference value. Therefore, it is not prone to the same limitations. While symmetry angle values tend to be smaller than symmetry index values, the measures are very highly correlated. This suggests that the symmetry angle is a good substitute for the symmetry index. Future studies of asymmetry may benefit from the use of the symmetry angle, as it is equally effective for identifying intra-limb differences as the symmetry index, but is not prone to problems due to normalization and provides a standard scale (+/-100%) to interpret results.
Orthopaedic Physical Assessment
  • D Magee
Magee, D., 1997. Orthopaedic Physical Assessment. W.B. Saunders Co, Philedelphia.
An assessment of the interexaminer reliability of tests for shoulder instability
  • Tzannes