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Ed INVITED REVIEW
Scapular dyskinesis: the surgeon’sperspective
Simon J Roche1, Lennard Funk2, Aaron Sciascia3 andW Ben
Kibler3
AbstractThe scapula fulfils many roles to facilitate optimal
function of the shoulder. Normal function of the shoulder joint
requires
a scapula that can be properly aligned in multiple planes of
motion of the upper extremity. Scapular dyskinesis, meaning
abnormal motion of the scapula during shoulder movement, is a
clinical finding commonly encountered by shoulder
surgeons. It is best considered an impairment of optimal
shoulder function. As such, it may be the underlying cause or
the
accompanying result of many forms of shoulder pain and
dysfunction. The present review looks at the causes and
treatment options for this indicator of shoulder pathology and
aims to provide an overview of the management of
disorders of the scapula.
Keywords
Dyskinesis, instability, scapula
Date received: 17th June 2015; accepted: 22nd June 2015
Introduction
Normal scapula function is essential for optimal shoul-der
function in all individuals and, in particular, theoverhead
throwing athlete. Scapula control and pos-itioning allows for
optimal positioning of the humerusin relation to the glenoid
transferring power from thecore to the distal upper extremity.
Abnormalities ofscapula function can be seen in many patients. It
pre-sents clinically as asymmetry in scapular motion com-pared to
the contralateral side, either in elevation ordescent, leading to a
disrupted motion.
In a static sense, it may present as a prominence ofthe scapula
or a resting position of protraction com-pared to the other side.
Scapular dyskinesis can bedefined as a collective term that refers
to movementof the scapula that is dysfunctional and may create
apossible impairment of overall shoulder function,although it may
also represent the cause of persistentshoulder symptoms or may be
the manifestation ofunderlying structural shoulder pathology in
manytypes of shoulder injury.1 In this review, we
explorecontemporary concepts in the understanding and man-agement
of scapular dyskinesis from the surgeon’sperspective.
Anatomical concepts of the scapula
The scapula is attached to the axial skeleton via theclavicle
through the acromioclavicular (AC) and ster-noclavicular joints. It
has muscular attachments to theposterior aspect of the ribcage via
trapezius, rhomboidsand serratus anterior. Core strength is
transferred viathe glenohumeral joint to the arm and hand by
optimalcoupling of the muscle activations and bony motion.The
scapula has relatively limited bony attachmentsand is therefore
dependent on mostly muscle activationfor mobility and
stability.
Normal movement of the scapula comprises compo-nents of three
motions: (i) upward/downward rotationaround a horizontal axis
perpendicular to the plane ofthe scapula; (ii) internal/external
rotation around a
1Royal Oldham Hospital, Oldham, UK2Wrightington Hospital, Wigan,
UK3Lexington Clinic, Lexington, KY, USA
Corresponding author:
Lennard Funk, Wrightington Hospital, Hall Lane, Appley Bridge,
Wigan
WN6 9EP, UK.
Tel: þ44 1625 545071Email: [email protected]
Shoulder & Elbow
2015, Vol. 7(4) 289–297
! The Author(s) 2015
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DOI: 10.1177/1758573215595949
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vertical axis through the plane of the scapula; and(iii)
anterior/posterior tilt around a horizontal axis inthe plane of the
scapula. The clavicle acts as a strut forthe shoulder complex,
connecting the scapula to theaxial skeleton. Normality of this
linkage enables twotranslations: (i) upward/downward translation on
thethoracic wall and (ii) retraction/protraction aroundthe rounded
thorax (Figure 1).2,3
The coupling of scapular external rotation, posteriortilt,
upward rotation and medial translation is calledretraction. The
coupling of internal rotation, angulartilt, downward rotation and
lateral translation iscalled protraction. The coupling of upward
translation,anterior tilt and internal rotation is seen as a
shrug.1
The scapula fulfils important functions in dynamicand static
modes. In addition to upward rotation, thescapula is required to
tilt posteriorly and externallyrotate to clear the acromion from
the moving arm inelevation and abduction. In addition, the scapula
mustbe able to internally/externally rotate in a synchronousmanner
to maintain the glenoid as a congruent socketfor the arm in motion,
thereby maximizing concavitycompression and ball and socket
kinematics. The scap-ula must be dynamically stabilized in a
position of
retraction during use of the arm to achieve maximalactivation of
all of the muscles that originate on thescapula.4,5
Another important role of the scapula in the normalshoulder is
as a link in the proximal to distal sequencingof velocity, energy
and forces of shoulder function. Inmost cases, sequencing begins at
ground level and indi-vidual body segments are coordinated by
muscle acti-vation and body position to generate, summate
andtransfer forces through these segments to the terminallink. This
sequence is termed the kinetic chain.6
The upper and lower trapezius muscles in addition tothe serratus
anterior muscles have been shown to be thegreatest contributors to
scapular stability and mobility(Figure 2).5,7 The trapezius and
serratus anterior mus-cles initiate upward rotation and posterior
tilt of thescapula. Activation of the lower trapezius muscleplays
an important role in the stability of the arm inthe overhead
position and in descent of the arm from aposition of maximum
elevation. The rhomboids assistthe trapezius in stabilizing the
scapula contributing tocontrol of medial and lateral scapular
translation.Latissimus dorsi and pectoralis minor, which are
bothextrinsic shoulder girdle muscles, affect scapular
Figure 1. Combined translational movements of the scapula in
three planes lead to protraction and retraction around the
thorax.
290 Ed Shoulder & Elbow 7(4)
-
motion in their role as prime movers of the arm. Thesemuscles
act mainly as force couples. The appropriateforce couples for
scapular stabilization include theupper and lower portions of the
trapezius muscle work-ing together with the rhomboid muscles,
paired with theserratus anterior muscle (Figure 3).8 The
appropriateforce couples for acromial elevation are the lower
tra-pezius and the serratus muscles working together pairedwith the
upper trapezius and rhomboid muscles.6
Scapular dyskinesis
Scapular dyskinesis (alteration of motion) is a term thatdenotes
loss of control of normal scapular motion,physiology or mechanics.
Dyskinesis as opposed to dys-kinesia is the more accurate
terminology because thelatter is applied to abnormal active
movementsmediated by neurological factors (e.g. tardive
dyskin-esia), whereas dyskinesis is more inclusive, incorporat-ing
many other factors that may be causative.1
Dyskinesis as a finding in the examination of theshoulder may be
the result of an injury, although itmay also not be related to any
form of previoustrauma. The clinical characteristics may include
prom-inence of the medial or inferomedial scapular border,early
scapular elevation or shrugging on arm elevationand/or rapid
downward rotation on lowering of thearm.9 The efficacy of shoulder
function is altered inmany ways, with resulting changes in 3D
glenohumeralangulation, AC joint strain, subacromial space
dimen-sions, maximal muscle activation and optimal arm pos-ition
and motion. This may result in augmentation ofpre-existing symptoms
related to concurrent shoulderpathology or produce new symptoms of
pain/discom-fort where none existed previously.
There are multiple causes of dyskinesis. Joint-relatedcauses
include high-grade AC arthrosis and instabilityand glenohumeral
joint internal derangement. Bonycauses include thoracic kyphosis,
clavicular fracturenon-union and clavicular malunion with
shortening,
Figure 2. Prime movers and stabilizers of the scapula: upper and
lower trapezius with serratus anterior.
Ed Roche et al. 291
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rotation or angulation. Neurological causes includepalsies of
the long thoracic or spinal accessory nervesand cervical
radiculopathy.
The commonest causative mechanisms of dyskinesishave a soft
tissue components, involving either intrinsicmuscle pathology or
inflexibility or inhibition of normalmuscle activation. Decreased
flexibility of either theshort head of biceps muscle or pectoralis
minor havebeen shown to create anterior tilt and protraction ofthe
scapula as a result of their pull on the coracoid.10
Periscapular muscle activation alterations may beseen in
patients with dyskinesis. Strength and activationof serratus
anterior are reduced in cases of impingement
and shoulder pain. This can cause a loss of posterior tiltand
upward rotation of the scapula leading to scapulardyskinesis.11
Regardless of the particular cause of dyskinesis, thefinal
result in most cases is a protracted scapula eitherat rest or with
the arm in motion. Protraction is notfavourable for optimal
shoulder function and results indecreased subacromial space with
increased symptomsof impingement and increased extrinsic rotator
cuffcompression. Rotator cuff strength can also bedecreased.4,5
Protraction can also lead to an increasein strain of the anterior
glenohumeral ligaments and agreater risk of internal
impingement.12
Figure 3. Force couples for scapula motion: in early elevation
(a, b), the upper and lower trapezius and serratus anterior
muscles
have long lever arms, being effective rotators and stabilizers.
With higher arm elevation (c), the upper trapezius moment arm
is
shorter, whereas the lower trapezius and serratus anterior
moment arms remain long, continuing to rotate the scapula. With
maximum arm elevation (d), the lower trapezius maintains scapula
position and the instant centre of rotation moves from
the medial border of the spine to the acromioclavicular joint
(adapted from Bagg SD, Forrest W).8
292 Ed Shoulder & Elbow 7(4)
-
Scapular dyskinesis and specific shoulder injuries
Labral injury. Scapular dyskinesis has a high associationwith
labral injury.13 The altered position and motion ofinternal
rotation and anterior tilt changes GH align-ment, placing increased
tensile strain on the anteriorligaments, increasing ‘peel-back’ of
the biceps/labralcomplex on the glenoid, and creating
pathologicalinternal impingement. These effects are magnified inthe
presence of glenohumeral internal rotation deficit,which creates
increased protraction as a result of ‘wind-up’ of the tight
posterior structures in follow-through.The demonstration of
dyskinesis in patients with sus-pected labral injury provides a key
component ofrehabilitation protocols. Correction of the symptomsof
pain found in the modified dynamic labral sheartest14 can be
frequently demonstrated by the additionof manual scapular
retraction. This indicates the pres-ence of dyskinesis as part of
the pathophysiology andthe need for scapular rehabilitation to
improve scapularretraction, including mobilization of tight
anterior mus-cles and institution of the scapular stability series
ofstrengthening exercises.
Impingement. Impingement is frequently seen in throw-ing
athletes. Most commonly in this group, impinge-ment is secondary to
other pathology such asinstability, labral injury or biceps
pathology. Scapulardyskinesis is associated with impingement by
alteringthe scapular position at rest and upon dynamic
motion.Scapular dyskinesis in impingement is characterized byloss
of acromial upward rotation, excessive scapularinternal rotation
and excessive scapular anteriortilt.15,16 These positions create
scapular protraction,which decreases the subacromial space and
decreasesdemonstrated rotator cuff strength.4,17
Activation sequencing patterns and strength of themuscles that
stabilize the scapula are altered in patientswith impingement and
scapular dyskinesis. Increasedupper trapezius activity, imbalance
of upper trapez-ius/lower trapezius activation, such that the lower
tra-pezius activates later than normal, and decreasedserratus
anterior activation have been reported inpatients with
impingement.15 Increased upper trapeziusactivity is clinically
observed as a shrug manoeuvre,resulting in a variation of the
scapular dyskinesis pat-tern. This causes impingement as a result
of a lack ofacromial elevation. Frequently, lower trapezius
activa-tion is inhibited or delayed, creating impingementbecause of
loss of acromial elevation and posteriortilt. Serratus anterior
activation has been shown to bedecreased in patients with
impingement, creating a lackof scapular external rotation and
elevation with armelevation.
The pectoralis minor has been shown to be shor-tened in length
in patients with impingement.
This tight muscle creates a position of scapular protrac-tion at
rest and does not allow scapular posterior tilt orexternal rotation
upon arm motion, predisposingpatients to impingement symptoms.
Rotator cuff injury. The rotator cuff is frequently
clinicallyinvolved in throwers with shoulder symptoms andsymptoms
can be exacerbated by dyskinesis. The dys-kinetic position that
results in an internally rotated andanteriorly tilted glenoid
increases the internal impinge-ment on the posterior superior
glenoid with arm exter-nal rotation and increases the torsional
twisting of therotator cuff, which may create the undersurface
rotatorcuff injuries seen in throwers.12 In addition, positions
ofscapular protraction have been shown to be limiting tothe
development of maximal rotator cuff strength.Recent work in
laboratory models of rotator cuff dis-ease has shown that
surgically induced scapular dyskin-esis results in changes in cell
morphology, geneexpression and tendon characteristics that are
similarto those seen in rotator cuff tendinopathy.18
AC joint injuries. AC joint injuries are rare in
throwingathletes except American football quarterbacks,although
they can create major functional deficits as aresult of the
disruption of the important AC linkage.Dyskinesis is found in a
high percentage of patientswith high-grade AC symptoms.19 AC
separationslessen and high-grade AC separations remove thestrut
function of the clavicle on the scapula. Loss ofthe strut function
permits the ‘third translation’ of thescapula, allowing it to move
inferior and medial to theclavicle, changing the biomechanical
screw axis of sca-pulohumeral rhythm, allowing excessive scapular
inter-nal rotation and protraction and decreased dynamicacromial
elevation when the arm is elevated.Iatrogenic AC joint injury as a
result of excessivedistal clavicle resection and detachment of the
AC liga-ments shortens the bony strut and allows excessivescapular
internal rotation as a result of excessive anter-ior/posterior
motion at the AC joint. The protractedscapular position creates
many of the dysfunctionalproblems associated with chronic AC
separations,including impingement and decreased demonstratedrotator
cuff strength. However, scapular and shoulderdysfunction can also
occur in type II injuries if the ACligaments are torn. This creates
an anterior/posteriorAC joint laxity and can be associated with
symptomsof pain, clicking, decreased arm elevation anddecreased
shoulder function.
If dyskinesis is demonstrated on the clinical examin-ation, then
increased attention should be directedtoward correcting the
biomechanical abnormalityrather than just placing the arm in a
sling. Treatmentshould include not only CC ligament
reconstruction,
Ed Roche et al. 293
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but also AC ligament reconstruction to completelyrestore the
screw axis mechanism.
Clavicle fractures. Clavicle fractures may produce dyskin-esis
if the anatomy is not completely restored. The dys-kinesis can be
associated with alterations in shoulderfunction such as decreased
strength and decreased armmotion in elevation.20 Shortened
malunions or non-unions decrease the length of the strut, and alter
thescapular position towards internal rotation and anter-ior tilt.
In addition to changes in length, changes inclavicle curvature or
rotation will affect scapular pos-ition or motion. Angulated
fractures result in func-tional shortening and loss of rotation.
The distalfragment in midshaft fractures often internally
rotates,decreasing the obligatory clavicle posterior rotationand
scapular posterior tilt during arm elevation.Dyskinesis can be a
clinical sign of potentially harmfulalteration of clavicle anatomy,
and can provide infor-mation to clarify indications for operative
treatment inthese fractures.
Clinical examination of the scapula
Evaluation of the scapula should be carried out as aroutine
component of the shoulder examination. Todetect scapular
dyskinesis, clinical observation is usedto determine whether
winging of the inferior or medialborders of the scapula is present.
Assessment for scapu-lar prominence because of lift off from the
thoracic wallis carried out in addition to detection of the lack of
asmooth coordinated movement of the scapula duringforward flexion,
shrugging or arm lowering from a pos-ition of full flexion. The
motion can then be character-ized as dyskinesis as a ‘yes’
(presence of deviation ordysrhythmia/asymmetry bilaterally or ‘no’
(no pres-ence). This scoring system has proven
interobserverreliability and clinical utility.21,22
A number of clinical tests have been devised thatemploy dynamic
corrective manoeuvres to assess theeffect of correction of
dyskinesis on shoulder symp-toms. The scapular assistance test
(SAT) and scapularretraction test (SRT) help evaluate the degree to
whichscapular dyskinesis, when corrected, may alter thepatient’s
symptoms. The SAT evaluates scapular con-tributions to impingement
and rotator cuff strengthwhereas the SRT can be used for evaluation
in casesof labral symptoms and rotator cuff strength.
To correctly carry out the SAT, assistance for scapu-lar
elevation is provided by manually stabilizing thescapula and
rotating the inferior border of the scapulaas the arm moves (Figure
4). This procedure simulatesthe force-couple activity of the
serratus anterior andlower trapezius muscles.23 If symptoms of
impingementare diminished or eliminated by this manoeuvre, then
rehabilitation of the scapular stabilizing muscles islikely to
help alleviate these symptoms.
The SRT involves manually stabilizing the scapula ina retracted
position on the thorax. This position confersa stable base of
origin for the rotator cuff and often willimprove tested rotator
cuff strength. This test fre-quently demonstrates scapular and
glenoid involvementin impingement lesions (Figures 5 and 6).23
Quantitative assessment of scapular stabilizerstrength can be
achieved by the lateral scapular slide
Figure 5. Scapula retraction test: the examiner stabilizes
the
medial border of the scapula as the arm is elevated. Relief
of
impingement symptoms is a positive test.
Figure 4. Scapula assistance test: the scapula is stabilized
with
one hand and the other hand ‘assists’ the scapula through
its
correct motion plane.
294 Ed Shoulder & Elbow 7(4)
-
test (Figure 7).6 This test is semi-dynamic and evaluatesthree
different positions of the scapula on injured andnon-injured sides
in relation to a fixed point on thespine as varying amounts of
loads are put on the sup-porting musculature. These positions offer
a gradedchallenge to the functioning of the shoulder musclesto
stabilize the scapula. The first position is with thearms by the
side. The inferomedial angle of the scapula
is palpated and marked on both the injured and non-injured
sides. The measurements from a fixed referencepoint are recorded.
The second position is with thehands on the hips, the fingers
anterior and the thumbposterior with approximately 10� of shoulder
extension.The new position of the inferomedial border of thescapula
is marked, and the reference point on thespine is maintained. The
distances are calculated on
Figure 7. Lateral scapula slide test. (a) Initial position with
arm at side. (b) Second position, arms on hips. (c) Third position
with
arms at 90� and internal rotation.
Figure 6. Scapula retraction test with resistance. (a) the
examiner performs a traditional ‘empty can’ test. (b) The
examiner
stabilizes the medial border of the scapula and repeats the
test. If the impingement symptoms are relieved, the test is
positive.
Ed Roche et al. 295
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both sides. A similar process is carried out for the
thirdposition. The arms are held at or below 90� of
forwardelevation with maximal internal rotation at the
gleno-humeral joint. The threshold of abnormality is 1.5 cmand
significant asymmetry is most commonly measuredin the third
position.
An essential part of scapula examination is evalu-ation of the
shoulder pathology or injury that couldbe causative of or
exacerbated by the concurrent pres-ence of scapula dyskinesis.
Rotator cuff integrity, labralstability and internal impingement
should be soughtbecause they may represent the underlying cause
ofthe dyskinesis.
Investigation and treatment of scapular dyskinesis
Investigations should be directed toward confirming anunderlying
diagnosis. Nerve conduction studies may beof value if a specific
traumatic precipitant causes injuryto the long thoracic nerve,
dorsal scapular nerve orspinal accessory nerve. Electromyography
studies canhelp identify injury and the potential for recovery
inperiscapular muscles. X-rays can help identify clavicleor AC
joint injury. Magnetic resonance imaging canhelp delineate muscle
injury, whereas MR arthrogramscan identify associated labral
pathology.
The mainstay of treatment for the scapulardyskinesis is physical
therapy to relieve the symptomsassociated with inflexibility or
trigger points and tore-establish muscle strength and activation
patterns.6,23
Dyskinesis can often be caused by muscle inhibitioncreated by
soft tissue related pathology such as labralinjury, internal
impingement or rotator cuff pathologyor hard tissue injury such as
clavicle fractures and ACseparations. In these instances, the
surgical problemshould be addressed prior to commencing physical
ther-apy to correct the dyskinesis.
Rehabilitation for scapular dyskinesis should startproximally
and end distally. The ultimate goal of phys-ical therapy is to
achieve the position of optimal scapu-lar function (i.e. posterior
tilt, external rotation andupward elevation). Core stability
exercises can helpimprove 3D control of scapular motion and this
isachieved through an integrated rehabilitation regimenin which the
larger muscles of the lower extremity andtrunk are utilized during
the treatment of the scapulaand shoulder. Scapular protraction and
retraction arefacilitated by hip and trunk flexion and
extensionexercises.
Once core stability has been established, a focus onthe scapular
controlling muscles can be initiated. Theserratus anterior muscle
acts as a powerful externalrotator of the scapula, whereas the
lower trapeziusacts as a stabilizer of the acquired scapular
position.Re-education of these muscles to act as dynamic
stabilizers of the scapula is achieved by employingshort lever,
kinetic chain assisted exercises and finallylong lever movements.2
This process may take at least6 months and appropriate patient
counselling to ensurerealistic expectations is essential in the
management ofthese cases. After achievement of adequate
scapularcontrol and retraction, other issues such as rotatorcuff
strength optimization or internal impingementcan then be addressed.
The sequence of rehabilitationexercises may need to be adapted for
individual casesbased on the rate of progress at each specific
stage.
Future directions
Although scapular dyskinesis is a proven clinical entitythat can
be responsible for shoulder pathology in manycases, there are still
a number of unanswered questionsthat require further clarification.
Dyskinesis seen inassociation with rotator cuff tears was
identified as afactor related to lower functional scores.25 It
remainsunclear whether scapular dyskinesis is a cause, effect
orcompensation for rotator cuff pathology.
Summary
Scapular dyskinesis is a relatively new concept in theassessment
of shoulder pathology. It is likely to be amajor contributor to
shoulder pain, particularly incases of recalcitrant shoulder pain
and dysfunction.Increasing evidence shows that the condition is
emi-nently treatable in the majority of cases and canimprove with
physiotherapy rehabilitation. It is advis-able that this condition
is recognized as a constituent ofthe routine shoulder examination
for shouldersurgeons.
Declaration of Conflicting Interests
The author(s) declared no potential conflicts of interest
withrespect to the research, authorship, and/or publication of
thisarticle.
Funding
The author(s) received no financial support for the
research,authorship, and/or publication of this article.
References
1. Kibler WB, Sciascia A and Wilkes T. Scapular dyskinesis
and its relation to shoulder injury. J Am Acad Orthop Surg
2012; 20: 364–372.
2. Kibler WB and Sciascia A. Current concepts: scapular
dyskinesis. Br J Sports Med 2010; 44: 300–305.3. McClure PW,
Michener LA, Sennett BJ and Karduna AR.
Direct 3-dimensional measurement of scapular kinematics
during dynamic movements in vivo. J Shoulder Elbow Surg
2001; 10: 269–277. 10.1067/mse.2001.112954
296 Ed Shoulder & Elbow 7(4)
-
4. Kibler WB, Sciascia A and Dome D. Evaluation ofapparent and
absolute supraspinatus strength in patientswith shoulder injury
using the scapular retraction test.
Am J Sports Med 2006; 34: 1643–1647.5. Smith J, Dietrich CT,
Kotajarvi BR and Kaufman KR.
The effect of scapular protraction on isometric shoulderrotation
strength in normal subjects. J Shoulder Elbow
Surg 2006; 15: 339–343. 10.1016/j.jse.2005.08.0236. Kibler WB.
The role of the scapula in athletic shoulder
function. Am J Sports Med 1998; 26: 325–337.
7. Kibler WB, Chandler TJ, Shapiro R and Conuel M.Muscle
activation in coupled scapulohumeral motionsin the high performance
tennis serve. Br J Sports Med
2007; 41: 745–749.8. Bagg SD and Forrest WJ. A biomechanical
analysis of
scapular rotation during arm abduction in the scapular
plane. Am J Phys Med Rehabil 1988; 67: 238–45.9. Kibler WB,
Ludewig PM, McClure P, Uhl TL and
Sciascia A. Scapular Summit 2009: introduction. July16, 2009,
Lexington, Kentucky. J Orthop Sports Phys
Ther 2009; 39: A1–A13.10. Borstad JD and Ludewig PM. The effect
of long versus
short pectoralis minor resting length on scapular kine-
matics in healthy individuals. J Orthop Sports PhysTher 2005;
35: 227–238.
11. Cools AM, Dewitte V, Lanszweert F, et al.
Rehabilitation of scapular muscle balance: which exer-cises to
prescribe? Am J Sports Med 2007; 35: 1744–1751.
12. Mihata T, McGarry MH, Kinoshita M and Lee TQ.Excessive
glenohumeral horizontal abduction as occurs
during the late cocking phase of the throwing motioncan be
critical for internal impingement. Am J SportsMed 2010; 38:
369–374.
13. Myers JB, Laudner KG, Pasquale MR, Bradley JP andLephart SM.
Glenohumeral range of motion deficits andposterior shoulder
tightness in throwers with pathologic
internal impingement. Am J Sports Med 2006; 34:385–391.
14. Kibler WB, Sciascia AD, Dome DC, Hester PW and
Jacobs C. Clinical utility of new and traditional exam
tests for biceps and superior glenoid labral injuries. AmJ
Sports Med 2009; 37: 1840–1847.
15. Ludewig PM and Reynolds JF. The association of scapu-
lar kinematics and glenohumeral joint pathologies.Journal of
Orthopaedic and Sports Physical Therapy2009; 39: 90–104.
16. Kebaetse M, McClure PW and Pratt N. Thoracic pos-
ition effect on shoulder range of motion, strength,
andthree-dimensional scapular kinematics. Arch Phys MedRehabil
1999; 80: 945–950.
17. Tate AR, McClure P, Kareha S and Irwin D. Effect ofthe
scapula reposition test on shoulder impingementsymptoms and
elevation strength in overhead athletes.
J Orthop Sports Phys Ther 2008; 38: 4–11.18. Reuther KE, Thomas
SJ, Tucker JJ, et al. Scapular dys-
kinesis is detrimental to shoulder tendon properties and
joint mechanics in a rat model. J Orthop Res 2014;
32:1436–1443.
19. Gumina S, Carbone S and Postacchini F. Scapular dys-kinesis
and SICK scapula syndrome in patients with
chronic type III acromioclavicular dislocation.Arthroscopy 2009;
25: 40–45.
20. McKee MD, Pedersen EM, Jones C, et al. J Bone Joint
Surg Am 2006; 88: 35–40.21. McClure P, Tate AR, Kareha S, Irwin
D and Zlupko E.
A clinical method for identifying scapular dyskinesis, part
1: reliability. J Athl Train 2009; 44: 160–164.22. Uhl TL,
Kibler WB, Gecewich B and Tripp BL.
Evaluation of clinical assessment methods for
scapulardyskinesis. Arthroscopy 2009; 25: 1240–1248.
23. Kibler WB and McMullen J. Scapular dyskinesis and
itsrelation to shoulder pain. J Am Acad Orthop Surg 2003;11:
142–151.
24. Kuhn JE, Plancher KD and Hawkins RJ. Scapular wing-ing. J Am
Acad Orthop Surg 1995; 3: 319–325.
25. Dunn W JG. Factors associated with low outcomes
scores in patients with full thickness rotator cuff
tears.American Academy of Orthopaedic Surgeons AnnualMeeting. San
Diego, CA, 2011.
Ed Roche et al. 297