Athletic Training and Sports Health Care

Pearls of Practice Supplemental Data

Evaluating Scapular Dyskinesis

Aaron Sciascia, PhD, ATC, PES

Abstract

The scapula is, at its core, a link within the kinetic chain (the coordinated, integrated proximal to distal muscle activity sequencing that allows arm tasks to occur).1 It has several crucial roles but, most importantly, it serves as the link that transfers energy from the large muscles of the trunk, lower extremity, and core to the smaller muscles of the arm during arm movements. The shoulder is often described as a “funnel” because the scapula directs the energy from the core to the arm similar to a funnel directing fluid into a specific container or reservoir.1

Scapular motion comprises complex rotations and translations, although it is often simplified clinically to single planar motion. The complex motions and translations are necessary to allow the scapula to function as part of scapulohumeral rhythm, the integrated coupled motion of the moving arm and scapula that is the basis for effective upper extremity use. The scapular rotations (anterior/posterior tilt, upward/downward rotation, and internal/external rotation) are described as accessory arthrokinematic motions, which means they are involuntary, similar to patellar or clavicular motion. Conversely, the scapular translations (elevation/depression and medial/lateral translation) can be characterized as physiologic motions such as the voluntary gross actions of humeral flexion, abduction, or rotation. Medial translation (dynamic movement of the scapula around the thorax posteriorly toward the vertebral column) and lateral translation (dynamic movement of the scapula around the thorax anteriorly toward the chest) should be used to describe active motion while retraction and protraction should be used to describe the end position of the scapula after the movement has ceased.2

The rotations and translations occur as a result of synchronous muscle contraction of many muscles. Although we clinically attempt to identify a specific muscle as lacking strength, flexibility, and/or endurance, our testing procedures are incapable of specific isolation. Simply stated, muscles do not work in isolation; therefore, clinicians may wish to reconsider an isolated approach to rehabilitation.

When scapular motion becomes altered, the appropriate term to use would be scapular dyskinesis. “Dys” (alteration of) “kinesis” (motion) is a general term that reflects loss of control of normal scapular physiology, mechanics, and motion. Scapular dyskinesis can be clinically characterized by medial or inferior medial border prominence, early scapular elevation or shrugging on arm elevation, and/or rapid downward rotation on arm lowering.3 It has been hypothesized that arm function suffers when scapular dyskinesis is present due to a strain between the glenoid and humerus relationship.3 However, a cause versus effect relationship between scapular motion and shoulder injury has not been established.4

During the past 5 years, the literature has consistently noted that scapular dyskinesis, in isolation, is not an injury or a musculoskeletal diagnosis but rather a physical impairment.4 The alteration of motion reduces the efficiency of shoulder function in several ways, including changes in three-dimensional glenohumeral angulation, acromioclavicular joint strain, subacromial space dimensions, maximal muscle activation, and optimal arm position and motion.4 Scapular dyskinesis is analogous to patellar tracking issues. When we see the patella moving in a pattern that is not centralized to the knee, we identify that as an impairment. However, the altered tracking has to have a cause, which can range from bony abnormalities to tissue tightness and/or weakness. Similarly, scapular dyskinesis should be viewed as an impairment with a causative origin.

Scapular dyskinesis can be divided into four categories5: neurological involvement, bony disruption, muscle disruption, or soft tissue impairment. Scapular dyskinesis with neurological, bony, or muscle disruption origins can be seen clinically but occurs infrequently compared to soft tissue impairments. Therefore, scapular dyskinesis due to soft tissue impairment is described below, whereas a chart has been provided…

The scapula is, at its core, a link within the kinetic chain (the coordinated, integrated proximal to distal muscle activity sequencing that allows arm tasks to occur).1 It has several crucial roles but, most importantly, it serves as the link that transfers energy from the large muscles of the trunk, lower extremity, and core to the smaller muscles of the arm during arm movements. The shoulder is often described as a “funnel” because the scapula directs the energy from the core to the arm similar to a funnel directing fluid into a specific container or reservoir.1

Scapular motion comprises complex rotations and translations, although it is often simplified clinically to single planar motion. The complex motions and translations are necessary to allow the scapula to function as part of scapulohumeral rhythm, the integrated coupled motion of the moving arm and scapula that is the basis for effective upper extremity use. The scapular rotations (anterior/posterior tilt, upward/downward rotation, and internal/external rotation) are described as accessory arthrokinematic motions, which means they are involuntary, similar to patellar or clavicular motion. Conversely, the scapular translations (elevation/depression and medial/lateral translation) can be characterized as physiologic motions such as the voluntary gross actions of humeral flexion, abduction, or rotation. Medial translation (dynamic movement of the scapula around the thorax posteriorly toward the vertebral column) and lateral translation (dynamic movement of the scapula around the thorax anteriorly toward the chest) should be used to describe active motion while retraction and protraction should be used to describe the end position of the scapula after the movement has ceased.2

The rotations and translations occur as a result of synchronous muscle contraction of many muscles. Although we clinically attempt to identify a specific muscle as lacking strength, flexibility, and/or endurance, our testing procedures are incapable of specific isolation. Simply stated, muscles do not work in isolation; therefore, clinicians may wish to reconsider an isolated approach to rehabilitation.

Scapular Dyskinesis

When scapular motion becomes altered, the appropriate term to use would be scapular dyskinesis. “Dys” (alteration of) “kinesis” (motion) is a general term that reflects loss of control of normal scapular physiology, mechanics, and motion. Scapular dyskinesis can be clinically characterized by medial or inferior medial border prominence, early scapular elevation or shrugging on arm elevation, and/or rapid downward rotation on arm lowering.3 It has been hypothesized that arm function suffers when scapular dyskinesis is present due to a strain between the glenoid and humerus relationship.3 However, a cause versus effect relationship between scapular motion and shoulder injury has not been established.4

During the past 5 years, the literature has consistently noted that scapular dyskinesis, in isolation, is not an injury or a musculoskeletal diagnosis but rather a physical impairment.4 The alteration of motion reduces the efficiency of shoulder function in several ways, including changes in three-dimensional glenohumeral angulation, acromioclavicular joint strain, subacromial space dimensions, maximal muscle activation, and optimal arm position and motion.4 Scapular dyskinesis is analogous to patellar tracking issues. When we see the patella moving in a pattern that is not centralized to the knee, we identify that as an impairment. However, the altered tracking has to have a cause, which can range from bony abnormalities to tissue tightness and/or weakness. Similarly, scapular dyskinesis should be viewed as an impairment with a causative origin.

Causes of Dyskinesis

Scapular dyskinesis can be divided into four categories5: neurological involvement, bony disruption, muscle disruption, or soft tissue impairment. Scapular dyskinesis with neurological, bony, or muscle disruption origins can be seen clinically but occurs infrequently compared to soft tissue impairments. Therefore, scapular dyskinesis due to soft tissue impairment is described below, whereas a chart has been provided to assist clinicians with understanding the presentation of scapular dyskinesis that arises from the other pathologic origins (Table A, available in the online version of this article).

Scapular Dyskinesis with Neurological, Bony, or Muscle Disruption Origins Scapular Dyskinesis with Neurological, Bony, or Muscle Disruption Origins

Table A:

Scapular Dyskinesis with Neurological, Bony, or Muscle Disruption Origins

Kinetic Chain Based

Weakness or tightness within proximal kinetic chain segments can create a dysfunctional scapula. For example, deficits at the hip or knee can create scapular dyskinesis by altering force generation or decreasing proximal kinetic chain motion or by placing the scapula in a biomechanically disadvantaged position.1 Clinically, this can be seen in overhead athletes with hip abductor weakness. For example, a high school shortstop has shoulder pain during throwing and has had difficulty throwing a live ball to first base. He throws the ball either over the first baseman's head or at his feet. His examination revealed no signs of internal derangement at the shoulder but he has mild scapular dyskinesis. When the patient steps to throw, his weak hip causes his pelvis to drop, which in turn causes his arm and scapula to drop. The lower positioned scapula causes the humeral head to contact the glenoid at a premature point in the throwing motion, thus creating pain. However, the hip weakness is the culprit. The noted scapular dyskinesis would be classified as a non-specific response to the loss of proximal activation and facilitation rather than a specific response to specific pathology.

Muscle Tightness/Inflexibility Based

Muscle tightness is a common factor that can result in scapular dyskinesis. Inflexibility of the muscles that insert on the coracoid process, including the pectoralis minor and the short head of the biceps, is common, as well as tightness of the infraspinatus/teres minor and latissimus dorsi muscles. Tightness in these muscles leads to the commonly seen rounded shoulder posture, which manifests as a protracted scapula at rest and/or with arm motion and increased scapular anterior tilt/internal rotation, resulting in a decrease in the subacromial space height and loss of scapular external rotation. These scapular mal-positions can be associated with symptoms that mimic external impingement, decreased rotator cuff strength, and internal impingement. The discovery of scapular dyskinesis with physical impairments but without obvious pathology should prompt the evaluation for kinetic chain or muscle inflexibility causative factors.

Examination

Considering the scapula is a link not only in the kinetic chain, but also between the core and arm tasked with transferring energy from the proximal structures to the distal extremity, evaluations focused on detecting potential deficiencies local and distant to the scapula (the legs, hips, and trunk and the scapula itself) should precede the traditional shoulder examination.4

Core Examination

The kinetic chain model suggests that improvement of common deficiencies within the core (immobility of the pelvis, hip, and/or trunk, muscular weakness of the same areas, and alterations in muscle recruitment and timing) would decrease the risk of injury to the upper extremity.1 Although no standard or universally accepted method to measure core strength or stability exists, a table of maneuvers and qualifying positive findings based on the author's clinical experience and expertise has been provided for clinical use (Table B, available in the online version of this article).

Scapular Evaluation Template

Table B:

Scapular Evaluation Template

Scapular Examination

Key elements for a consistent scapular evaluation are clinical observation of the presence or absence of scapular dyskinesis and demonstration of the effects of corrective maneuvers (Table B). Clinical experience has demonstrated that posterior weakness is often seen in combination with other impairments, especially tightness of the muscles attaching to the coracoid process. Coracoid-based inflexibility can be assessed by palpation of the pectoralis minor and the short head of the biceps brachii at their insertion on the coracoid tip. The muscles will usually be tender to palpation, even if they are not symptomatic in use, can be traced to their insertions on the ribs and arm as taut bands, and will create symptoms of soreness and stiffness when the scapulae are manually maximally retracted and the arm is slightly abducted to approximately 40 to 50 degrees.

Thoracic and rib mobility may be assessed for hypermobility or hypomobility using standard anterior/posterior gliding techniques. The acromioclavicular joint should be evaluated for joint tenderness or instability. Acromioclavicular joint laxity can be evaluated by stabilizing the clavicle with one hand and grasping and mobilizing the acromion in an anterior/posterior direction with the other hand. The integrity of the sternoclavicular joint may also be assessed by performing an anterior/posterior mobilization.

Identifying the presence or absence of scapular dyskinesis is best accomplished through the scapular dyskinesis test.4 The examination is conducted by having the patient raise the arms in forward flexion to maximum elevation, and then lower them three to five times. If the clinician is not sure if an alteration of motion is present, the patient can be asked to repeat the scapular dyskinesis test with a 3- to 5-pound weight in each hand. The added weight may help accentuate any altered motion. This motion requires activation of the muscles to maintain the open chain mechanism of scapulohumeral rhythm. Failure to maintain this rhythm can result in increased scapular internal rotation, with consequent medial border prominence. The scapular dyskinesis is more easily observed in the descent phase of arm motion. Prominence of any aspect of the medial scapular border on the symptomatic side is recorded as “yes” (prominence detected) or “no” (prominence not detected) (Figure 1).

Example of scapular dyskinesis.

Figure 1.

Example of scapular dyskinesis.

Three muscle tests should be performed: manual resistance of the arm at 130 degrees of flexion (targets the serratus anterior) (Figure 2A), manual resistance of the arm at 130 to 150 degrees of abduction (targets the lower and middle trapezius) (Figure 2B), and extension of the arm at the side (targets the rhomboids) (Figure 2C).4 If the clinician can “break” the patient's arm position and the scapula is visibly moving out of position, then each test would be positive for scapular weakness.

Manual muscle test for the (A) serratus anterior and (B) lower and middle trapezius showing (left) starting and (right) end positions, and (C) rhomboid muscles.

Figure 2.

Manual muscle test for the (A) serratus anterior and (B) lower and middle trapezius showing (left) starting and (right) end positions, and (C) rhomboid muscles.

Finally, corrective maneuvers designed to “correct” scapular motion and/or scapular positioning should be employed.4 The scapular assistance test (SAT) helps evaluate scapular contributions to shoulder pain based on motion alterations; the scapular retraction test (SRT) evaluates scapular contributions to rotator cuff strength; and the low row evaluates contributions to arm strength.

In the SAT, the examiner applies gentle pressure to assist scapular upward rotation and posterior tilt as the patient elevates the arm (Figure 3A). A positive result occurs when the painful arc during arm motion is relieved and the arc of motion is increased.

(A) Scapular assistance test. (B) Scapular retraction test showing the (left) nonscapula and (right) stabilized testing component. (C) Low row test. The arm is first tested without gluteal contraction then followed up with retesting with gluteal contraction.

Figure 3.

(A) Scapular assistance test. (B) Scapular retraction test showing the (left) nonscapula and (right) stabilized testing component. (C) Low row test. The arm is first tested without gluteal contraction then followed up with retesting with gluteal contraction.

In the SRT, the examiner first grades the strength in forward flexion following standard manual muscle testing procedures (Figure 3B, left). The examiner then places and manually stabilizes the medial border of the scapula in a retracted position (Figure 3B, right). A positive result occurs when the demonstrated strength increases when the scapula is in the retracted position and stabilized by the clinician.

In the low row test (LRT), the patient is asked to place his or her arm in slight humeral extension and then instructed to resist movement of the arm into forward flexion (Figure 3C). The examiner (positioned posterior to the patient) then instructs the patient to contract the gluteal muscles while applying the same anterior force on the arm. If strength increases with the gluteal contraction, this is an indication that scapular and shoulder muscle activation may be facilitated by involving hip and core strength, which suggests lower extremity/core strengthening should be included in the treatment plan for the shoulder.

A positive result on the SAT, SRT, or LRT informs the clinician that the rehabilitation should primarily focus on scapular mobility, scapular strength, or core strength rather than take a rotator cuff activation or strengthening focus.

Major Clinical Take Home Points

  1. Scapular kinematics and muscle activations should not be viewed as single planar, isolated actions but rather be appreciated as complex, intricate actions.

  2. Scapular dyskinesis is a physical impairment, not a diagnosis.

  3. Altered scapular motion can be seen with various shoulder pathologies including nerve injury, bony injury, muscle detachment injury, and, most commonly, with soft tissue impairments seen at both the upper and lower extremity.

  4. The scapula is a link in the kinetic chain; therefore evaluation of the scapula should include an assessment of areas and regions local (scapula and shoulder) and distant (trunk and legs) to the scapula.

  5. Clinical examination of the scapula should include assessment of core strength and stability, scapular position, scapular motion, muscle strength, and corrective maneuvers.

References

  1. Sciascia A, Thigpen C, Namdari S, Baldwin K. Kinetic chain abnormalities in the athletic shoulder. Sports Med Arthrosc Rev. 2012;20(1):16–21. doi:10.1097/JSA.0b013e31823a021f [CrossRef]22311288
  2. Ludewig PM, Lawrence RL. Mechanics of the scapula in shoulder function and dysfunction. In: Kibler WB, Sciascia AD, eds. Disorders of the Scapula and Their Role in Shoulder Injury: A Clinical Guide to Evaluation and Management. Switzerland: Springer; 2017:7–24. doi:10.1007/978-3-319-53584-5_2 [CrossRef]
  3. Kibler WB, Ludewig PM, McClure PW, Uhl TL, Sciascia AD. Scapula Summit 2009. J Orthop Sports Phys Ther. 2009;39(11):A1–A13. doi:10.2519/jospt.2009.0303 [CrossRef]19881011
  4. Kibler WB, Ludewig PM, McClure PW, Michener LA, Bak K, Sciascia AD. Clinical implications of scapular dyskinesis in shoulder injury: the 2013 consensus statement from the ‘Scapular Summit.’Br J Sports Med. 2013;47(14):877–885. doi:10.1136/bjsports-2013-092425 [CrossRef]23580420
  5. Kibler WB, Sciascia A, Wilkes T. Scapular dyskinesis and its relation to shoulder injury. J Am Acad Orthop Surg. 2012;20(6):364–372. doi:10.5435/JAAOS-20-06-364 [CrossRef]22661566

Scapular Dyskinesis with Neurological, Bony, or Muscle Disruption Origins

Category When you see: What it could mean: How to detect the pathology:
Neurological Winging = scapular motion is altered from the initiation of arm movement through the end of arm movement Possible damage to the nerves supplying the scapular stabilizing muscles (long thoracic nerve, spinal accessory nerve, or dorsal scapular nerve) Step 1: patient reports traumatic injury or traction mechanism where arm was forcefully pulled away from the body Step 2: visual observation by the clinician noticing medial border prominence from the beginning of arm movement to the end of the movement Step 3: referral for diagnostic electromyography
Bony Disruption Altered scapular position following clavicle fracture The clavicle functions as a strut to maintain scapular position and to guide and constrain scapular motions during muscle activations and arm motions. Therefore, clavicle fractures can result in a loss of the strut, and alter normal scapular position and motion. The distal clavicle fragment is connected to the scapula through the intact acromioclavicular (AC) joint, and the scapula will move on the thorax as the distal clavicle fragment moves. Step 1: patient reports traumatic injury Step 2: visual observation by the clinician noticing clavicular deformity and altered scapular position at rest (increased anterior tilt and internal rotation) and during arm movement Step 3: referral for radiographic imaging
Altered scapular motion following high-grade AC injury. This alteration may be clinically manifested as scapular dyskinesis and be associated with a spectrum of subsequent shoulder symptoms such as pain, limited motion, clicking/catching/grinding/popping, and weakness. The AC joint, stabilized by both the coracoclavicular and AC ligaments, represents the critical link in coordinated scapuloclavicular kinematics and scapulohumeral rhythm. An AC joint disruption or injury may disrupt scapular kinematics; ultimately, multiplanar arm motion is altered because of a disruption to the screw axis of the coordinated motion (the screw axis is the rotational axis by which the acromioclavicular articulation moves around). Step 1: patient reports traumatic injury Step 2: visual observation by the clinician noticing deformity at the AC joint and altered scapular position during arm movement Step 3: referral for radiographic imaging Key Note: if deformity is present but NOT scapular dyskinesis, rehabilitation may be attempted. If deformity and scapular dyskinesis are both present, surgical treatment may be a consideration
Muscle Disruption Altered scapular position at rest and scapular dyskinesis with motion; posttraumatic onset of localized and intense pain (average pain rating 8 out of 10 at rest and with movement) along the medial scapular border; weakness of the rhomboids and lower trapezius; difficulty placing and maintaining the scapula in a retracted position; limitations of arm use away from the body in forward flexion or overhead positions; increased upper trapezius activity and spasm, resulting from lack of lower trapezius activity, creates migraine-like headaches Traumatic detachment of the lower trapezius and rhomboids not allowing proper scapular positioning or motion Step 1: patient reports a traction-type injury to the arm, which would include but not be limited to seat belt– restrained motor vehicle accidents, direct trauma to the scapular muscles, a repetitive overload tensile mechanism such as throwing, catching or lifting a heavy object with the arm at full extension, or pulling against a heavy object. Step 2: visual observation by the clinician noticing scapula in a static position of protraction and lateral deviation away from the vertebral column and medial border prominence during arm motion Step 3: point tenderness from the superior angle down the length of the medial border of the scapula Step 4: palpable defect detected similar to a “divot” between the rhomboid and medial border of the scapula Step 5: referral to orthopedic shoulder specialist

Scapular Evaluation Template

Component Test Positive Finding(s) Result
Kinetic Chain Single Leg Stance Trendelenburg sign □Yes □No
Single Leg Squat 1/3 squat (instead of ½ squat) □Yes □No
Trunk lean □Yes □No
Valgus Knee □Yes □No
Corkscrew □Yes □No

Posture Head position Forward head □Yes □No
Shoulder position Shoulder levels not symmetric □Yes □No
Forward, rounded shoulders □Yes □No
Taught pectoralis minor □Yes □No
Taught biceps brachii (short head) □Yes □No
Scapular position at rest Inferior angle prominence □Yes □No
Medial border prominence □Yes □No
Superior angle prominence □Yes □No
Spinal Alignment Thoracic kyphosis □Yes □No
Lumbar lordosis □Yes □No
Scoliosis □Yes □No

Special Testing Vertebral mobility Hypermobile □Yes □No
Within normal limits □Yes □No
Hypomobile □Yes □No
Costovertebral mobility Hypermobile □Yes □No
Within normal limits □Yes □No
Hypomobile □Yes □No
Rib mobility Hypermobile □Yes □No
Within normal limits □Yes □No
Hypomobile □Yes □No
AC joint mobility Hypermobile □Yes □No
Within normal limits □Yes □No

Scapular Movement Elevation in scapular plane 3-5x (add weight if unsure) Dyskinesis on descent □Yes □No

Manual Muscle Testing Use 1–5 MMT grading or dynamometer readings Forward Elevation to 130° Involved: ____
Non-Involved: ____
Scapular alteration □Yes □No
Abduction to 130°–150° Involved: ____
Non-Involved: ____
Scapular alteration □Yes □No
Extension at side Involved: ____
Non-Involved: ____
Scapular alteration □Yes □No

Corrective Maneuvers Scapular Assistance Test Improved ROM with assistance □Yes □No
Scapular Retraction Test Increased strength during resisted flexion in plane of the scapula when scapula is stabilized □Yes □No
Low Row Test Increased strength in extension when gluteal muscles are activated □Yes □No
Authors

From the Department of Exercise and Sport Science, Eastern Kentucky University, Richmond, Kentucky.

The author has no financial or proprietary interest in the materials presented herein.

Correspondence: Aaron Sciascia, PhD, ATC, PES, Department of Exercise and Sport Science, Eastern Kentucky University, 228 Moberly Building, 521 Lancaster Avenue, Richmond, KY 40475. E-mail: aaron.sciascia@eku.edu

10.3928/19425864-20191107-01

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