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It is only in recent years that specific tests have been developed to assess the function of the scapula. The measurement properties of these tests are still being investigated.
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The scapula should be assessed with most upper quarter conditions, and the examination should include the scapula dyskinesis test, modified scapula assistance test, scapula reposition test, pectoralis minor length, thoracic kyphosis/flexibility, flexibility of posterior capsule of the glenohumeral joint, and muscle performance testing for the primary scapular stabilizers: lower trapezius, middle trapezius, and serratus anterior.
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One key principle in designing a scapular exercise program is to match the difficulty of the exercise with the patient’s level of motor control and strength. It is important to observe the patient posteriorly during an exercise to assure that he or she is able to maintain good scapular control.
Scapular dysfunction is a common clinical problem, and proper scapular motion and stability is considered to be crucial to normal function of the shoulder. The scapula is required to serve as a stable base for glenohumeral function but is also required to move through a substantial arc of motion. This motion is required to maintain optimal muscle length-tension relationships and glenohumeral joint alignment and stability during elevation of the arm.
The goals of this chapter are to: (1) describe normal and abnormal motion of the scapula, (2) discuss the relationship between scapular dyskinesis and shoulder pathology, (3) describe current examination techniques for identifying possible scapular pathology, and (4) describe intervention techniques for scapular pathology including enhancing muscle performance, stretching, bracing, and taping.
Normal Scapular Motion
The basic anatomy of the shoulder girdle and the scapular muscles is covered in Chapter 4 ; therefore, this section will focus on describing scapular motion and the primary muscles and other factors controlling this motion. The terminology used to describe scapular motion is quite varied in the literature and no definitive standard has emerged, but we have promoted using scapular and clavicular angles to accurately describe scapular orientation and position, respectively. Three scapular rotations are typically used to describe scapular orientation, and these are depicted in Figure 93-1A–C . Upward/downward rotation of the scapula occurs around an axis that is perpendicular to the plane of the scapula. Anterior/posterior tilting (sometimes called tipping ) occurs around an axis through the spine of the scapula. Posterior tilting involves the inferior angle of the scapula moving anteriorly and the superior border moving posteriorly. Internal/external rotation occurs around a vertically oriented axis, and external rotation involves the lateral border of the scapula moving away from the thorax. More precise biomechanical definitions of these axis systems are available in original sources.
Scapular position on the thorax has been described in various ways using terms that correspond to superior-inferior or medio-lateral translation of the scapula from its normal resting position between the second and seventh ribs. However, because the clavicle acts as a strut, the scapula remains at a fixed medio-lateral position relative to the thorax (assuming an intact acromioclavicular joint and clavicle). Therefore, the rotational motion of the clavicle around the sternoclavicular joint into protraction/retraction and elevation/depression can be used to describe scapular position in two degrees of freedom. The description of scapular position using these two clavicular angles can be likened to the identification of a point on the earth using two angles, longitude and latitude. As shown in Figure 93-1D and E , clavicular elevation and depression occur around an anterior-posterior axis through the sternoclavicular joint, and clavicular protraction and retraction occur around a vertical axis through the sternoclavicular joint. Therefore, the motions of “scapular elevation or depression” and “scapular protraction or retraction” really occur in conjunction with corresponding rotary motions at the sternoclavicular joint.
During elevation of the arm there is a consistent pattern of scapular upward rotation, posterior tilting, and external rotation, along with clavicular elevation and retraction. Figure 93-2 shows the normal pattern for each of these motions in healthy subjects derived using a sensor attached directly to the scapula via bone pins during arm raising and lowering in the scapular plane. This figure shows each of the scapular and clavicular rotations separately with humerothoracic motion plotted along the x-axis.
As evidenced by Figure 93-2A , scapular upward rotation, there is a much greater contribution from the glenohumeral joint than the scapulothoracic joint in the early phase of elevation. After 90 degrees of arm elevation, the contribution from the glenohumeral joint and the scapulothoracic joint become almost equal. Scapular upward rotation is controlled primarily by a force couple between the upper and lower trapezius and the serratus anterior.
Posterior tilting ( Fig. 93-2B ) and external rotation ( Fig. 93-2C ) motions are nonlinear, with the majority of these motions not occurring until after 90 degrees of arm elevation. While specific muscle activity associated with these motions has not been demonstrated directly, the lower fibers of the serratus anterior and lower trapezius are positioned to produce posterior tilting and the middle trapezius is positioned to produce external rotation. Weakness in these muscles following nerve injury has been clearly associated with scapular winging, which is attributable to excessive anterior tilting and scapular internal rotation.
The clavicular retraction ( Fig. 93-2D ) observed suggests that the superior aspect of the scapula normally moves posteriorly during arm elevation while the scapula also moves superiorly as represented by clavicular elevation ( Fig. 93-2E ). These motions are attributable to all parts of the trapezius muscle.
Abnormal Scapular Motion (Scapular Dyskinesis)
A commonly observed abnormal pattern of scapular motion (scapular dyskinesis) is the premature or excessive scapular elevation that appears as shrugging ( Fig. 93-3 ). This pattern has been associated with rotator cuff pain, weakness, and fatigue. It has also been observed with loss of glenohumeral motion. Therefore, excessive or early elevation of the scapula is a sign of scapular compensation for a weak rotator cuff and/or a stiff glenohumeral joint capsule. This shrugging motion has been associated with increased upper trapezius activity. Abnormal eccentric control of scapular rotation during arm lowering may also occur. The normal pattern of scapular downward rotation during arm lowering is shown in Figure 93-2B and is quite linear. Clinically, this should appear as a smooth descent of the scapula during arm lowering. We have commonly observed that poor eccentric control of this scapular downward rotation appears as a rapid dumping of the scapula instead of smooth downward rotation ( Fig. 93-4 ). We are unaware of experimental documentation of this kinematic abnormality.
Another common form of scapular dyskinesis is scapular winging wherein either the inferior angle or medial border of the scapula become more prominent. Inferior angle prominence would be associated with anterior tilting of the scapula, while medial border prominence would be associated with excessive scapular internal rotation. We have documented these motion abnormalities in our laboratory on subjects with long thoracic nerve injuries ( Fig. 93-5 ) affecting the serratus anterior muscle. Another source that may contribute to scapular winging is the action of the pectoralis minor muscle. If this muscle is tight or overactive, it has the ability to tilt the scapula forward, producing winging of the inferior angle as well as scapular depression ( Fig. 93-6 ). Borstad has presented data suggesting that subjects with tight pectoralis minor muscles demonstrate greater anterior tilting and scapular internal rotation.
Is Scapular Dyskinesis Related to Shoulder Pathology?
Recognition of the biomechanical role of the scapula in normal shoulder function has led to several clinical studies attempting to associate abnormal scapular motion, “scapular dyskinesis,” with shoulder pathology such as shoulder impingement or instability. These studies have included several methods of capturing scapular motion including Moiré topography, electromechanical digitization, radiographic methods, MRI, and electromagnetic tracking devices. Results of studies assessing three-dimensional scapular motion in those with pathology have been inconsistent. Subjects with shoulder impingement have been found to demonstrate increased posterior tilting, decreased posterior tilting, decreased upward rotation, increased upward rotation, increased superior translation, and increased internal rotation. In addition to the variability of findings in these studies, the magnitude of differences between those with healthy shoulders and those with pathology is typically small, in the 3 to 5 degree range, and it is unclear whether these differences, although statistically significant, are really of clinical significance. Furthermore, in a recent study in overhead athletes, we failed to find an association between shoulder symptoms and abnormal scapular motion. Despite some authors claiming a strong relationship between abnormal scapular motion and shoulder pathology, the actual research evidence supporting this assertion is limited. Other clinical tests predicated on altering symptoms with manual scapula repositioning may hold promise in clarifying which patients truly have scapular dysfunction driving their symptoms.
Specific Nerve Injuries
The spinal accessory and long thoracic nerves are two nerves commonly injured that lead to scapular muscle dysfunction, primary winging, and related shoulder disability. The spinal accessory nerve (cranial nerve XI) is derived from the ventral rami of C2, C3, and C4. It runs behind the sternocleidomastoid muscle and then emerges more superficially over the levator scapula to innervate the trapezius muscle. Due to its relatively superficial course, it is more susceptible to injury. Spinal accessory nerve injury has been reported to occur following blunt trauma, traction, lymph node biopsy in the posterior cervical triangle, and radical neck dissection. In the case of trapezius weakness, the shoulder appears depressed with the scapula translated laterally and the inferior angle rotated laterally. Winging will be most apparent with frontal plane abduction to 90 degrees.
The long thoracic nerve originates from the ventral rami of the C5, C6, and C7 cervical nerves. The nerve passes around the middle scalene muscle then reaches the upper slip of the serratus anterior muscle and descends along its anterior surface. This nerve can be damaged from viral illness, repetitive trauma, stretching, or surgery. Long thoracic nerve injury produces weakness of the serratus anterior and results in primary winging most evident during sagittal plane elevation. The scapula is described as being superiorly elevated and medially translated, with the inferior pole medially rotated.
Friedenberg retrospectively reviewed 106 patients with either long thoracic or spinal accessory neuropathy with a mean follow-up of 48 months. They found that with conservative care 40/50 patients with long thoracic injury and 37/56 patients with spinal accessory neuropathy obtained a good outcome. A traumatic injury mechanism was associated with a poorer outcome, but electrodiagnostic findings were generally not predictive of outcome. With closed injuries, recovery is often spontaneous but may require up to one year. For patients in whom substantial weakness persists for longer than 6 months, procedures may be warranted. For more information on nerve injuries about the shoulder, see Chapter 57 .
Examination
Evidence exists supporting the notion that altered scapular kinematics in a subset of persons may decrease the subacromial space, and that either this may therefore contribute to subacromial impingement or the altered kinematics may be a compensatory mechanism for the shoulder pathology. In light of this, clinicians need to be able to identify persons with scapular motion abnormalities. A scapular assessment measure should have clinical feasibility and acceptable reliability and validity. The measure should also assess dynamic, three-dimensional motion during concentric and eccentric loaded conditions, as would be present during athletics and occupational endeavors. Following is a description of existing clinical measures of scapular motion.
Two-Dimensional Tests
Lateral Scapula Slide Test and Modifications of Linear Tests
Kibler has described a measurement of scapular stability devised for use at static positions during arm elevation. The lateral scapular slide test involves taking a linear measure from the inferior angle of the scapula to the spinous process of the thoracic vertebrae and defines an “abnormality” threshold of 1.5 cm in side-to-side linear measurement difference in any of three test positions: with the arms resting at the sides, with the hands placed on the hips, and with the arms actively abducted to 90 degrees and internally rotated ( Fig. 93-7A–C online). The reported reliability of this method was done on the actual linear measurements, not the difference in linear measures between sides at the different arm positions. Although Kibler cites a study reporting intertester reliability to be between 0.77 and 0.85, a replication of the original study found significant differences between the two testers on all Kibler measures. Odom et al. reported inter-rater intraclass correlation coefficients ranging from 0.52 to 0.66 for the measurement of scapula side-to-side differences for subjects with shoulder dysfunction and 0.75 to 0.80 for subjects without shoulder impairment. The standard error of measures sometimes exceeded the mean value of the difference. Based on these results, the value of the difference in side-to-side scapular distance measurements with this technique was not found to be reliable in determining the presence and amount of scapular asymmetry.
Other researchers have described modifications of the lateral scapular slide in the seated position, using overhead upper extremity positions, using string to measure linear distance, and additionally calculating normalized scapular abduction (the linear distance from T3 to the inferior angle of the acromion divided by the scapular size). The findings of these studies are inconsistent, but the use of a linear measure from the spinous process to a designated point on the scapula has inherent drawbacks irrespective of the reliability and validity issues. First, use of only a linear horizontal or oblique measure along the thorax does not address displacement of the scapula’s medial border or inferior angle away from the thoracic wall (winging). Additionally, in a study of 71 collegiate athletes who participated in one-arm-dominant sports, 52 of the 71 subjects exhibited a difference of at least 1.5 cm on one or more of the three positions assessed for the lateral scapular slide test. The calculated specificity of 26.8% in this study questions the usefulness of asymmetry as an indicator of pathology. In support of this finding, Nijs et al. report no association between the results of the lateral scapular slide and measures of pain and disability in a group of 29 patients diagnosed with a shoulder disorder.
SICK Scapula Rating Scale
Based on the concept of the SICK scapula (scapular malposition; inferior medial border prominence; coracoid pain and malposition; dyskinesis of scapular movement), linear measures of asymmetry have been described for use in throwers. With the arms by the side, three static measurements are taken: (1) infera, which is the difference between the vertical height of the superomedial angle of the inferior scapula in centimeters and that of the contralateral scapula; (2) lateral displacement, which is the difference of the horizontal distance of superomedial scapular angle from midline between the inferior scapula and the contralateral scapula; and (3) abduction, which is the difference between scapulas in angular measure of the medial scapular border from a midsagittal plumbline using a goniometer. Based on these static measurements as well as subjective complaints and other clinical examination findings, a 20-point rating scale has been devised for use as a measure of severity of symptoms. The authors acknowledge, however, that superficial landmarks have less than optimal reliability, but state that this scale is used as a qualitative measure of severity and progress assessment. A recent study performed on athletes performing repetitive overhead activities did support the assertion that static abnormalities with the arm at the side were associated with altered scapular kinematics found with dynamic movement, especially in the lower ranges of elevation.
Visual Schemes
Although several authors recommend assessing the scapula visually and some even report statistics of abnormal scapula motion patterns, they either do not provide operational definitions or fail to substantiate their assessment methods with reliability or validity studies. Bak and Faunl observed scapulohumeral rhythm while standing behind competitive swimmers who were performing repeated abduction. They defined scapulothoracic instability as either scapular winging or asynchronous motion, but offer no reliability of their assessment measures. In 2004, Bulut and colleagues reported on the reliability of rating scapular position on 29 patients with shoulder pain. Two physical therapists rated scapula position as being either symmetrical or asymmetrical, and also described the scapula as either normal, inferior angle winging, or medial border winging. Winging was operationally defined as being able to place the finger under the respective location (inferior angle or medial border). Poor intertester reliability with κ coefficients ranging from –0.20 to 0.16 was reported for visual inspection of scapular position using this method, and rating occurred only with static shoulder position with the arms by the side.
Classification System Developed By Kibler et al
Rating during active arm elevation, operational definitions, and reliability measures are provided in a visual classification system reported by Kibler et al., who define scapular dyskinesis as “the observable alterations in the position of the scapula and the patterns of scapular motion in relation to the thoracic cage.” They describe a system in which dyskinesis is categorized into three types: type I, inferior angle prominence; type II, medial border prominence; type III, translation of the scapula superiorly with prominence of the superior medial border. These categories correspond to abnormalities occurring about the three scapular axes, respectively: transverse, vertical, and perpendicular to the scapular plane. A type IV category designates normal, symmetrical scapular motion. A reliability study was undertaken using this system in which subjects performed frontal and scapular plane elevation while being videotaped from behind. Tapes were reviewed and rated by two physicians and two physical therapists. κ coefficients were used to measure agreement. Inter-rater reliability was 0.42 between the physical therapists and 0.31 between the physicians. Intratester reliability was 0.5. Although these values are not high enough to support the use of their system as described, the authors suggest that with refinement, reliable visual analysis of scapular dysfunction may be possible.
Scapula Dyskinesis Test
We have recently developed a visually based test to identify abnormal motion called the scapular dyskinesis test (SDT) that has demonstrated validity and has satisfactory reliability. The SDT involves viewing the exposed posterior thorax during elevation of the upper extremities in both the sagittal plane (flexion) and coronal plane (abduction) while grasping 3- to 5-pound (1.4–2.3 kg) dumbbells. Motion patterns are rated as normal, “obvious,” or “subtle” dyskinesis using the operational definitions in Box 93-1 .
Definitions of terms
Normal scapulohumeral rhythm: Scapula is stable with minimal motion during initial 30 to 60 degrees of humerothoracic elevation, then smoothly and continuously upwardly rotates during elevation and smoothly and continuously downwardly rotates during humeral lowering with no evidence of winging.
Scapular dyskinesis : Either or both of the following motion abnormalities
Dysrhythmia: Scapula demonstrates premature or excessive elevation or protraction, non-smooth or stuttering motion during arm elevation or lowering, or rapid downward rotation during arm lowering.
Winging: There is posterior displacement of the medial border and/or inferior angle of the scapula away from the posterior thorax.
Scapular Dyskinesis Rating Scale for Each Test Movement
N = Normal motion: no evidence of abnormality
S = Subtle abnormalities: mild/questionable evidence of abnormality, not consistently present
O = Obvious abnormalities: striking, clearly apparent abnormalities, evident on at least 3/5 trials (dysrhythmias or winging of 1 inch or greater displacement of scapula from thorax)
To determine the reliability of this system, 142 athletes competing in a collegiate sport that required repetitive overhead activity were recruited. This population was chosen due to the high incidence of shoulder pathology reported among athletes participating in sports requiring overhead arm use.
To determine the reliability of this system, 142 athletes competing in a collegiate sport that required repetitive overhead activity were recruited. This population was chosen due to the high incidence of shoulder pathology reported among athletes participating in sports requiring overhead arm use. Each subject performed five repetitions of bilateral active weighted shoulder flexion (sagittal plane) and bilateral active weighted shoulder abduction (coronal plane) while they were videotaped from a posterior view. For subjects under 150 pounds (68 kg), 3-pound (1.4-kg) weights were held. For those weighing 150 pounds (68 kg) or greater, 5-pound (2.3 kg) weights were held. The test movements were based on previous pilot studies by these researchers and Johnson et al. that found that active movements with resistance resulted in abnormal scapular motion more often than static tests in subjects with shoulder pathology.
All examiners underwent standardized training via a self-instructional PowerPoint (Microscoft Corp.) presentation including operational definitions, photographs, and embedded video examples. Six raters (three separate pairs consisting of two athletic trainers and two pairs of experienced physical therapists) independently viewed randomly selected videotaped athletes and rated their shoulders as having obvious dyskinesis, subtle dyskinesis, or normal motion ( Fig. 93-8A,B )
We found moderate inter-rater reliability (average κ = 0.54 for video raters) in classifying scapular motion patterns as either normal, or having subtle or obvious dyskinesis, which is a higher κ value than reported using the Kibler method. Our system did not distinguish between subtypes of dyskinesis, as we observed that the subtypes described in the Kibler method often occurred simultaneously. The SDT also included loaded tasks, which can alter scapular kinematics. There is also evidence that muscular fatigue, which may occur with repetition, directly affects scapulohumeral rhythm and may result in compensatory increased rotation or destabilization of the scapula, so we feel that repetitive motion is necessary for proper evaluation.
To determine the validity of the SDT, athletes judged as having either “normal” motion or “obvious dyskinesis” underwent kinematic testing with an electromagnetic tracking system while performing weighted flexion and abduction, and the data from both groups were compared. Significant differences during arm elevation were found between the “normal” and “obvious dyskinesis” groups, with the latter group demonstrating less scapular upward rotation, less clavicular elevation, and greater clavicular protraction. These alterations have previously been associated with subacromial impingement. The suprahumeral structures, namely the rotator cuff, subacromial bursa, and long head of the biceps, probably undergo greater compression with reduced upward rotation. Kamkar and colleagues propose that upward rotation of scapula due to the serratus anterior activity is essential in preventing the humeral head from impinging on the acromion. The finding of less clavicular elevation in the dyskinesis group is consistent with the description of the SICK scapula syndrome, in which the scapula appears clinically as a “dropped” or lower scapula on the involved side in symptomatic throwing athletes. The scapulas in the dyskinesis group were more protracted than the normal group. Solem-Bertoft et al. found a reduction in the opening width of the subacromial space with the scapula in a protracted position compared with a retracted position using MRI. Our finding of greater protraction in those with dyskinesis may be relevant to the compression of structures within the subacromial space. The finding that shoulders visually judged as having dyskinesis have distinct alterations in three-dimensional scapular motion provides validity for the use of the SDT.
Under clinical conditions, use of the SDT is recommended using the test movements of repeated flexion and abduction, with the priority given to flexion if high irritability is encountered as this motion was more likely to evoke dyskinesis. To use this test, active elevation to at least 90 degrees is required. While these authors found that weighted shoulder was more provocative than if done without weights, there are some instances wherein using weights is not feasible due to pain or significant weakness.
Symptom Alteration Tests
The aim of symptom alteration tests is to infer that scapular pathology exists if an improvement in symptoms is found when applying manual forces to the scapula during provocation testing. The scapula assistance test described by Kibler is the application of a lateral and upward rotatory force to the medial border of the scapula during arm elevation to determine if symptoms of impingement were reduced or abolished. By assisting upward rotation, this test was reported to facilitate the action of the scapular rotators, primarily the serratus anterior–lower trapezius force couple, to elevate the arm and simultaneously assess the effect on pain. Reliability and validity have not been studied, but its concept provided the basis for further research regarding the potential identification of scapular pathology in those with shoulder pain.
Modified Scapula Assistance Test
Rabin described the modified scapula assistance test, in which posterior tilting was facilitated in addition to assisted upward rotation as described in the original scapula assistance test. This modification was based on several studies that found reduced posterior tilting in those with symptoms of shoulder impingement. The inter-rater reliability of the modified scapula assistance test was tested by two raters on 46 patients with shoulder pathology. Patients were asked to rate their pain using a typical 11-point verbal rating scale to describe their symptoms during arm elevation in the scapular and sagittal planes. Arm elevation and rating were then repeated while the tester applied a posterior tilting force with one hand by pulling back on the superior aspect of the scapula and concurrently using the heel of the hand to apply a lateral and upward rotary force to the inferior angle. A 2-point decrease in pain was considered clinically significant. κ values and percentage agreement for elevation in the scapular plane and sagittal plane were 0.53, 77% and 0.62, 91%, respectively, indicating moderate reliability and thus making it acceptable for clinical use. These authors recommend performing the test using the patient’s more painful arc of motion, in either the scapular or sagittal plane ( Fig. 93-9 ).
Scapula Retraction Test
The scapula retraction test has been described as stabilization of the scapula in a retracted position on the thorax by manual application of force along the medial border of the scapula. Kibler et al. measured pain using a numeric rating scale, and elevation strength using a hand-held dynamometer during isometric shoulder elevation in the scapular plane with the scapula in its natural position and then manually retracted using the scapula reposition test. This was performed in a group of 20 patients diagnosed with shoulder pathology and in 10 asymptomatic controls. The researchers reported an increase in shoulder elevation strength using the scapula retraction test position compared to testing with the scapula in its natural “rest” position in 100% of their patients. No warm-up trials were reported, and the natural position was always tested first, so strength gains may have been due to a practice or testing-order effect instead of manual repositioning. In addition, this test was described using two examiners (one to apply the retraction and another to measure the strength using a dynamometer), which may be clinically impractical.
Scapula Reposition Test
Smith et al. found decreased elevation strength with maximal scapular retraction, and these authors confirmed this finding during pilot testing. Therefore, we modified Kibler’s test by emphasizing posterior tilting and external rotation of the scapula but avoiding full retraction, and named it the scapula reposition test (SRT).
The effect of the SRT on elevation strength and shoulder impingement was studied in 142 collegiate athletes who were engaged in sports requiring repetitive overhead movements. As part of the examination, three tests for impingement (Neer, Hawkins, and Jobe ) were performed as originally described with the scapula in its natural resting posture. If any of these tests were found to be positive for symptom provocation, the athlete was asked to rate his or her pain. Any pain-provoking test was then repeated with the scapula manually repositioned using the SRT. The SRT was performed by grasping the scapula with the fingers contacting the acromioclavicular joint anteriorly while remaining medial to the lateral acromial border. The palm and thenar eminence contact the spine of the scapula posteriorly, with the forearm obliquely angled toward the inferior angle of the scapula to provide additional support on the medial border ( Fig. 93-10 ). This encourages scapular posterior tilting and external rotation (inferior angle and medial border moved anteriorly toward thorax) and approximates the scapula to a midposition on the thorax. As the SRT was applied, the impingement test(s) that originally provoked pain were repeated and the athlete again rated his or her pain.
Isometric elevation strength in the Jobe’s test position (arm elevated to 90 degrees in the plane of the scapula and internally rotated by pointing the thumb down) was also measured using a hand-held dynamometer. Testing consisted of three repetitions of 5-second maximum isometric shoulder elevation contractions with the scapula in its natural position and also with the scapula manually repositioned using the SRT.
Almost half of the athletes had a reduction in pain during impingement testing with scapular repositioning, with a clinically significant strength gain in 26% of athletes with at least one positive shoulder impingement test, which amounted to about 10% strength increase with the SRT. Strength gains may have been facilitated simply by providing a more stable proximal fixation for the muscles such as the deltoid and rotator cuff used to perform shoulder elevation, or may have been the result of an improved length-tension relationship of the rotator cuff or scapular musculature secondary to an altered scapular position. A finding of increased shoulder elevation strength with scapular repositioning may provide a clinical test to identify the subset of those with shoulder pathology that may benefit from interventions designed to improve scapular musculature function.
In the clinical setting, we recommend asking for a pain rating (0–10) during resisted shoulder elevation in the Jobe’s “empty can” position with the shoulder elevated to 90 degrees in the plane of the scapula and maximally internally rotated. Manual resistance may be applied directly, or a hand-held dynamometer can be used for more objective strength assessment. The Jobe’s test should then be repeated using the SRT. A finding of a 2-point decrease in pain rating or a significant increase in strength using the SRT denotes a positive test and implies that suboptimal scapular orientation or position may be contributing to the patient’s symptoms, which suggests the need for interventions addressing the scapula.
Muscle Performance
Muscle performance is evaluated using a make test (subject uses maximal isometric force against stationary resistance) and graded as normal, reduced, or markedly reduced compared with the uninvolved extremity using the following operational definitions:
Normal (N): Strong, with equal resistance applied as compared bilaterally
Reduced (R): Mild to moderate deficit as compared bilaterally
Markedly Reduced (MR): Significant deficit as compared bilaterally (little to no resistance can be applied)
The muscles to be tested are the prime movers of the scapula, namely the serratus anterior and the lower and middle trapezius. The testing positions have been described by Kendall and verified electromyographically as eliciting maximal muscle activity.
Middle Trapezius
The patient is prone and the shoulder is placed in a position of horizontal abduction and external rotation (thumb up) with scapula adducted toward midline. Pressure is applied against the forearm in a downward direction while the trunk is manually stabilized. Monitor the medial border of the scapula and grade on the ability to maintain scapular retraction ( Fig. 93-11 online).
