Which movement is not associated with the scapula

Kinematics and EMG data are presented in Table 1. For pattern I dyskinesis, 3 PCs explained a total of The first PC For pattern II dyskinesis, 3 PCs explained a total of The contour plots of 4-muscle EMG with scapular upward rotation and posterior tipping in the X and Y axes respectively are presented in Fig.

Muscle activities were unique to patterns of dyskinesis. Impaired scapular kinematics and associated muscle activation are thought to result in shoulder disorders such as pain, restricted range of motion, and functional disability. Based on these assumptions, researchers have identified insufficient posterior tipping, external rotation, and upward rotation; decreased serratus anterior and lower trapezius activity; and increased upper trapezius muscle activity in patients with shoulder impingement 16 , 18 , 20 , 21 , Understanding the scapular kinematics and associated muscle activities unique to specific patterns of scapular dyskinesis would be important if the consequences of such alterations are correlated to clinical outcomes and injury mechanisms, especially in overhead athletes.

Main findings of our study showed different characteristics in pattern I and pattern II dyskinesis. Our results provide a method of analysis and identify the characteristics of the kinematics and muscle activities that are distinctive to patterns of scapular dyskinesis in subjects performing overhead sports. Principle component analysis of the scapular kinematics and muscle activities in different patterns of dyskinesis has not been reported previously.

Theoretically, scapular kinematics and associated muscle activities during arm movements should share similar variance. External rotation was described as accessory movement characteristics in third PC in pattern II dyskinesis. Thus, change of muscle activation may not be obviously corresponding to scapular movement during arm elevation in pattern II dyskinesis.

The results indicated that activation of the scapular muscles plays primary roles as stabilizers and secondary roles as movers of the scapula in patients with pattern II dyskinesis. This may explain why specific muscle activities and theoretically associated scapular kinematics were not found to be highly related in past research Clinically, this raises the question of whether specific muscle training can change scapular kinematics 27 , 28 , Further research is needed to validate this assumption.

Other studies have reported that excessive activity of the UT combined with reduced activity of the LT and SA was observed during arm elevation in patients with shoulder impingement 18 , Consistent with previous findings, the moderate correlations 0. This finding implies that these muscles are activated together as a force couple during arm movement.

Scapular muscle activations are unique to each pattern of dyskinesis. Additionally, the contour lines and plots expressed the functions of the observed or hypothetical muscle activations on two kinematic variables upward rotation and posterior tipping. The UT has previously been shown to elevate the scapula and extend the neck, while the MT acts to retract the scapula. Additionally, the SA functions as scapular upward rotator and external rotator 20 , For inferior angle prominence of scapula pattern I , muscle function of MT, LT and shared variance in the first PC with upward rotation and posterior tipping can be explained to stabilize the axis for scapular upward rotation by MT and to function posterior tipping of the scapula by LT during arm elevation.

However, the activation of LT cannot generate adequate scapular posterior tipping against the scapular inferior angle in pattern I dyskinesis. On the other hand, activated SA was not associated with generating scapular external rotation against the scapula medial border in pattern II dyskinesis. In clinical implication, evaluation of MT and LT muscle activations, as shared the same major variance with scapula kinematics, should be considered to correct inferior angle prominence of pattern I scapula dyskinesis subjects.

On the other hand, without shared the variance with scapular kinematics in medial border prominence pattern II dyskinesis subjects, UT, MT and SA activations are likely to play major roles in stabilization of scapula instead of movement of the scapula.

Instead of scapular muscle training, correction of medial border prominence dyskinesis may consider other factors, like soft tissue tightness or posture. Validation of this assumption should be further investigated.

The limitations of this study should be noted. Further studies need to confirm our findings of movement characteristics in different scapular dyskinesis patterns. Second, the kinematics data were measured with humeral elevation of less than degrees to reduce the error of the skin-based method.

Third, movement artifacts and crosstalk cannot be excluded with the use of surface electrodes during dynamic movements. Third, results from testing arm elevation in scapular plane may not represent results during functional movement or overhead sport activity. Additionally, participants were generally young and participated in overhead sports in this study. Sedentary or elderly people may have different scapular movement and muscle activation.

For the inferior angle prominence dyskinesis, the major characteristics are coactivation of middle and lower trapezius and corresponding scapular posterior tipping and upward rotation.

This study was a cross-sectional study. All participants performed arm elevation in the scapular plane. The characteristics of the scapular kinematics and associated muscle activities specific to patterns of dyskinesis were identified. One hundred thirty-four subjects with unilateral shoulder pain and scapular dyskinesis were recruited for this study. The inclusion criteria were 1 age of 20 to 40 years old, 2 with unilateral shoulder pain of less than 5 on a point visual analog scale during arm elevation and 3 demonstration of inferior angle or medial border of scapula prominence during arm elevation.

Exclusion criteria were a history of stroke, diabetes mellitus, rheumatoid arthritis, rotator cuff tear, surgical stabilization of the shoulder, osteoporosis, or malignancies in the shoulder region. Participants who had pain or disorders of the cervical spine, elbow, wrist, or hand, who had pain radiating from the shoulder to the arm, or who could not elevate their arms to degrees were also excluded.

They received written and verbal explanations of the purposes and procedures of the study. All subjects gave written informed consent to the Research Ethics Committee of the National Taiwan University Hospital approval number RINA following a complete explanation of this study, and in accordance with the Declaration of Helsinki. Karduna et al. The details of the methodology can be found in a previous paper Three sensors were placed in locations where the skin motion artifact was minimized sternum, acromion, distal humerus.

Anatomic landmarks sternal notch, xiphoid process, seventh cervical vertebra, eighth thoracic vertebra, acromioclavicular joint, root of the spine of the scapula, inferior angle of the scapula, lateral epicondyle, and medial epicondyle were palpated and used for subsequent receiver mounting and landmark digitization.

Surface EMG electrodes were placed on the upper trapezius UT, midway between the acromion and C7 , middle trapezius MT, midway between the root of the spine of the scapula and T3 , lower trapezius LT, on the line between the spine of the scapula and T7 and serratus anterior SA, anterior to the latissimus dorsi and posterior to the pectoralis major of the involved shoulder.

The referenced electrode was placed on the ipsilateral clavicle. Maximal voluntary isometric contraction MVIC was tested and used to normalize the sEMG data during the task for the UT, resisted shoulder flexion of 90 degrees; for the MT, resisted horizontal abduction while lying prone with the arm abducted to 90 degrees; for the LT, resisted arm elevation while lying prone with the arm abducted in line with muscle fibers; and for the SA, resisted arm elevation of degrees.

Two single patterns with inferior angle of the scapula prominence pattern I and medial border of the scapula prominence pattern II and the mixed pattern with combination of the two single patterns were selected in this study. Kinematics and sEMG data were collected during arm elevation in the scapular plane. Participants were asked to elevate the arms that the dumbbells in each hand weighed 2. Raw kinematic data were low-pass filtered at a 6-Hz cutoff frequency and converted into anatomically defined rotations.

In general, we followed the ISB guidelines for constructing a shoulder joint coordinate system Then the data were normalized to the MVIC trials. The EMG data of each muscle were the average of the middle 3 trials. Descriptive statistics of kinematics and EMG data were calculated.

This analysis yielded the amount of variance explained by each principal component, and also the correlations between principal components PCs and the 3-dimensional scapular kinematics and 4 muscles EMG. Additionally, the characteristics of movements of the dyskinesis patterns were demonstrated by contour plots of 4-muscle EMG with scapular upward rotation and posterior tipping in the X and Y axes, respectively.

Kibler, W. Br J Sports Med. Current concepts: scapular dyskinesis. Article PubMed Google Scholar. Uhl, T. Evaluation of clinical assessment methods for scapular dyskinesis. Kawasaki, T. Does scapular dyskinesis affect top rugby players during a game season? J Shoulder Elbow Surg. Otherwise, as an imaging modality, ultrasound isn't used much for the diagnosis of the snapping scapular syndrome. Once the diagnosis has been made, the physician's attention turns to treatment.

Much research and study has been directed at finding conservative nonoperative ways to successfully treat this syndrome. Physiotherapists have taken front and center stage on this one.

Different theories and different approaches have been tried and tested. Addressing any postural issues is considered the first step. Making sure the head, neck, and shoulders line up and work together in a coordinated way with the rest of the body is part of a rehab approach called the kinetic chain model.

Kinetic chain rehab is very much like the old song that says the neck bone's connected to the shoulder bone and the shoulder bone's connected to the elbow and so on. Each body part moves in relation to all the other body parts from head to toe. Creating a rehab program for scapular dyskinesia takes into account all postural components, not just around the head, neck, shoulder, or scapula. Core training as well as individual muscle strengthening progresses through a stepwise program over a period of 10 to 12 weeks.

The patient is guided through the acute phase to recovery and beyond into a maintenance phase. The goal is to restore dynamic scapular control, muscle endurance, and a return to the normal glenohumeral-to-scapulothoracic rhythm. These treatment tools can aid in pain control and indirectly contribute to recovery from the poor motor control that is the center of scapular dyskinesia.

Where there is pain, the can be altered movement. Reducing or eliminating that pain, can help muscles resume normal movement patterns. If these measures don't achieve the desired results and especially if there are bone spurs or tumors involved, then surgery might be the next step.

Surgery is not advised in cases where there is not an identified lesion causing this syndrome. Surgery is considered first when the patient gets relief from the pain and snapping after a trial injection of local anesthetic provides pain relief.

When surgery is called for, the surgeon may remove a portion of the scapula that is prominent and rubbing against the rib cage. This procedure is called scapular dissection. Other soft tissues might also be dissected such as the inflamed bursa, bone spurs, or fibrous tendons. Any surgery in this area comes with an increased risk of nerve damage, as there are several nerves there that can be very easily cut by accident during the procedure.

Surgery may be done with an open incision. This approach gives the surgeon a better chance to see the various structures affected and identify what's going on. But more and more, arthroscopic surgery has replaced open treatment.

Arthroscopy is less invasive, reduces the amount of cutting and disruption to the soft tissues, creates fewer cosmetic problems, and shortens hospital stays. In some cases, the surgeon may choose to use a combination of open and arthroscopic approaches.

Studies show that the bursa is easily removed with arthroscopy but any bone removal may be better approached with an open incision. Surgery is followed by immobilization in a sling for several weeks. This gives time for the soft tissues to recover, especially when the muscles have been cut away from the bone as part of the procedure. Rehab follows the period of immobility in order to restore motion, strength, and function.

The authors of this review article on the topic of snapping scapular syndrome conclude by saying that this problem has been around for a long time. In fact, the first case was reported in during the post-civil war era. This syndrome probably isn't going to disappear overnight. The spine and acromion are the origin of the deltoid muscle consisting of 3 parts: anterior, middle and posterior and insertion of the trapezius muscle.

Differences in the activity of each of the bellies of the deltoid muscle have been observed. When the arm is in abduction, the posterior portion of the deltoid acts as an external rotator. This is an important fact in patients with massive rotator cuff tear affecting the infraspinatus and teres minor muscles. Moreover, differences in the action of the uppermost fibers of the trapezius have also been observed in patients with symptomatic and asymptomatic rotator cuff tears.

When the patient is symptomatic it is possible to observe an increase in the activation of the upper trapezius due to compensation of the elevation deficit by an increase in shoulder rotation. Moreover, small differences in scapular kinematics have been observed among patients with and without subacromial impingement. Patients suffering impingement presented a slight increase in upward rotation of the tip of the scapula, along with elevation of the clavicle during flexion movements and a slight increase in posterior translation and inclination of the clavicle during elevation in the plane of the scapula.

These differences have relative clinical importance, but represent compensatory movements which, in a certain way, can contribute to an overload of the scapular spine and the acromial process. Fragility fractures are one of the main types of stress fracture and usually occur when a normal load is applied to a bone whose mechanical characteristics are weakened due to a deficiency of elasticity. They can occur virtually anywhere in the skeleton and are associated with multiple conditions, such as rheumatoid arthritis, osteoporosis, Paget's disease, osteomalacia and rickets, renal osteodystrophy and bone irradiation.

The loss of the mechanical properties of a bone due to a decrease in bone mineral density in a long bone can be partially compensated by changes in the diameter of its diaphysis. However, this compensatory mechanism does not take place in cancellous bone, thus increasing the risk of fractures due to mechanical overloads.

Out of the 5 cases similar to ours described previously, 6—8 1 had undergone prior radiotherapy on the area due to breast cancer, another case, an year-old female, had been diagnosed with osteoporosis, and the last case, a year-old female, had not been diagnosed with any disease, but her age and gender allowed us to assume the presence of associated osteoporosis.

The history of our 2 patients included diminished biomechanical properties of their bones. One had a long history of corticosteroid therapy, whilst the other had been diagnosed with severe osteoporosis through bone densitometry.

Therefore, the authors suggest that this type of fracture, very rare in this location, requires the combination of 3 factors. Firstly, the presence of a rotator cuff injury, which, as observed in the cases presented, can range from a massive tear thereof to a smaller lesion which alters its functionality.

Secondly, an increase in activity due to the previous injury of the muscles with origin and insertion in the spine of the scapula or base of the acromion, during arm lifting movements. Lastly, the presence of decreased bone mineral density and changes in the microarchitecture as is the case in osteoporosis which make the bone biomechanically inferior to normal bone.

These 3 etiological factors would cause a disruption in the kinematics of the scapula to compensate the glenohumeral dysfunction, which would eventually lead to a fracture in this location. Aside from the etiopathogenesis of the fracture, and offering a more clinical view, we could add that in all 3 cases it was possible to establish the diagnosis through physical examination and simple radiography.

The presence of pain over the spine and base of the acromion in patients with the aforementioned predisposing factors rotator cuff dysfunction and bone fragility should immediately make us think of this type of fracture, which may be easily confirmed by a complete radiographic study in 3 planes. It is not necessary to perform bone scintigraphy scans, and magnetic resonance imaging has only been used to assess the condition of the rotator cuff, reserving CT scans for the follow-up of fractures displacement and consolidation process.

Regarding treatment, common fractures of the spine of the scapula and base of the acromion normally associated with high-energy trauma are generally non-displaced fractures and their treatment is often conservative.

One of them was due to an absence of progression in the consolidation process, and the other due to persistence of pain. Roy et al. Two of the 3 cases reported in this article eventually required open reduction and osteosynthesis with a plate. The presence of persistent pain and absence of consolidation were the 2 criteria followed to indicate an intervention. Conservative treatment was only applied in 1 case, in a patient suffering a bilateral fracture. Although consolidation was not achieved, pain and function improved with rehabilitation, and the demands of the shoulder decreased as the operated contralateral shoulder improved and assumed tasks which it could not perform previously.

We agree with Roy et al. For these reasons, the authors propose surgical treatment thereof. A parallel issue would be that related to rotator cuff injury, whose treatment must be individualized according to the degree of injury rehabilitation treatment, rotator cuff repair or inverted arthroplasty, depending on each case, in order to achieve a normalization of shoulder kinematics. Level of evidence iv. The authors declare that no experiments were performed on humans or animals for this study.

The authors declare that no patient data appear in this article. Rev Esp Cir Ortop Traumatol. ISSN: Previous article Next article. Issue 5. Pages September - October More article options. Stress fracture of the scapular spine associated with rotator cuff dysfunction: Report of 3 cases and review of the literature. Download PDF. Corresponding author. This item has received. Article information. Two of them needed osteosynthesis and bone grafting, and the third one became a painless non-union.

As we believe that these fractures are unstable, and non-union would be expected, their surgical management is recommended. Scapular spine fracture. Palabras clave:. Full Text. Introduction Stress fractures of the scapular spine or the base of the acromion are unusual. Case reports Case 1 The patient was a year-old, right handed female without any prior history of trauma and with a history of systemic lupus erythematosus with 23 years evolution, who was following treatment with corticosteroids.

Figure 1. Figure 2.