Snapping Scapula Syndrome

Journal of Sport Rehabilitation, 1994,3, 331-352
0 1994 Human Kinetics Publishers, Inc.
Snapping Scapula Syndrome
Larry W. Mattocks and Susan L. Whitney
Snapping scapula syndrome is a symptom, not a diagnosis. Soft tissue
pathology and bony abnormalities can lead to scapular noise. Anatomy and
biomechanics of the scapulothoracic mechanism are reviewed prior to
discussion of the possible pathology that may lead to scapular noise and
pain. Key points concerning the differential diagnosis are covered briefly.
Guidelines are presented for rehabilitation of the patient with soft tissue
lesions causing scapular pain and noise.
Although often overlooked, the scapulothoracic articulation can be a site
of dysfunction in the shoulder girdle. Scapular pain is often attributed to some
vague syndrome (30,3 1,37); however, in the majority of cases a true anatomical
basis for the pathology can be found (37). Snapping or grating scapular syndrome
is a disorder characterized by palpable or audible noise emanating from the
scapulothoracicregion (9,33-35,41,46,58). The term snapping scapula actually
refers to a sign or symptom and is not a true diagnosis. A thorough examination
in most cases will determine the cause of the noise and pain (37). The purpose
of this communication is to provide a brief introduction to snapping scapula
and to describe the symptoms, etiology, differential diagnosis, and treatment of
snapping scapula syndrome.
The first case of snapping scapula was reported in 1867 by Boinet (5), and
the first report to be found in the American literature was a single case reported
by McWilliams in 1914 (29). In 1933, Milch and Burman reviewed the available
literature, presented an additional six cases of snapping scapula, and classified the
various etiologies (35). Milch reported in 1950 that snapping scapula was not a
rare condition but had not received much attention in the medical literature (33).
The noise of scapular snapping occurs during movements of the scapula
and can be highly variable. The quality of the noise may be grating, thumping,
clicking, or snapping; the sound may be a single noise or a series of sounds that
occurs during movement of the scapula over the thorax (33-35). The incidence
of scapular noise was frequent enough to prompt a French physician to classify
the sounds in a manner similar to the classification of breath sounds. Mauclaire
Lany W. Mattocks is with Penn-Ohio Rehabilitation, 1559 N. Hermitage Road,
Hermitage, PA 16148. Susan L. Whimey is with the Department of Physical Therapy,
University of Pittsburgh, -Pittsburgh, PA 15261.
Mattocks and Whitney
332
identified three types of sounds: fioissement, frottement, and craquement.
Froissement is a low-friction-type sound and is considered to be due to normal
physiology of the region. Frottement is somewhat louder and may be grating or
clicking in nature. Noise of this nature may represent an underlying pathology.
Craquement is a very loud snapping that may be audible across a room and is
undoubtedly due to pathology of the scapular region (28, 33, 34, 41).
Milch differentiated between scapular crepitus and true scapular snapping.
Milch felt that crepitus was due to changes in the underlying soft tissue, while
snapping was a result of bone sliding over bone (33-35). Current literature most
commonly refers to either snapping scapula or scapular crepitus following Milch's
classification. In this paper, snapping scapula will be used in cases of loud
audible snapping due to bony etiology. Scapular crepitus will refer to scapular
noise of soft tissue origin.
Snapping scapula and scapular crepitus are often used as diagnostic labels;
however, scapular noise is only a symptom. Multiple causes of scapular noise
have been postulated. The myriad of possible causes can be distilled into three
categories: (a) crepitus due to soft tissue changes between the scapula and the
thorax (9, 16, 33-35,53, 55, 58), (b) snapping due to bony changes in the fit of
the scapula on the thorax (9, 33-35, 41, 46, 53, 58), and (c) noise of unknown
etiology (7-9, 34, 53, 58) (Table 1).
Anatomy
The scapulothoracic articulation is often referred to as one of four joints that
make up the shoulder complex; however, the scapulothoracic articulation is not
a joint but a functional gliding mechanism that provides both mobility and stability
to the shoulder complex. Generally, the scapula moves smoothly over the thorax,
guided by the coordinated action of the scapular muscles. Movement of the
Table 1 Reported Causes of Snapping Scapula Syndrome
Pathology
Causes
Bony pathology
Osteochondroma (33, 34,55)
Abnormal curvature of scapula (9, 33-35, 41,46, 55)
Exostosis of scapula or ribs (9, 33, 41, 53)
Fracture of scapula or ribs (34,35)
Tuberculosis of scapula or ribs (35,55)
Omovertebral bone (33,34, 55)
Subscapular bursae (33,34, 50, 55)
Muscular atrophy (33-35, 55, 58)
Inflammatory changes (33,34)
Elastofibroma (16)
Proposed: poor posture (7-9, 34, 58)
Muscular weakness (53)
Soft tissue pathology
Unknown pathology
Snapping Scapula
333
scapula is highly dependent on motion of the acromioclavicularand sternoclavicular joints. In essence, the scapula is a part of a closed kinetic chain made up of
the scapula, clavicle, sternum, and respective articulations (14, 39).
The scapula is a triangular-shaped, flat bone that normally is situated
approximately 2 in. lateral to the vertebral column and rests between the second
and seventh ribs (39, 52). The costal surface of the scapula is slightly concave
to approximate the convex posterior aspect of the thorax. Important features of
the scapula include the spine, acromion process, coracoid process, glenoid, medial
border, and inferior angle.
The scapular spine divides the dorsal surface into a smaller upper portion
and a much larger lower portion. The upper portion, or supraspinous fossa, gives
rise to the supraspinatus muscle of the rotator cuff. Below the scapular spine is
the infraspinous fossa, which gives rise to the infraspinatus muscle, an important
external rotator of the humerus and part of the rotator cuff. The scapular spine
is also an important point of insertion for the upper, middle, and lower portions
of the trapezius muscle.
The acromion process is the enlarged, flattened end of the spine of the
scapula. Functionally, the acromion acts as the roof of the glenohumeral joint,
lending a measure of protection to sensitive structures that pass beneath it. The
deltoid muscle, a powerful elevator of the humerus, has its origin in part from
the acromion. The acromion articulates with the clavicle, forming the acromioclavicular joint.
The elongated, thickened, most lateral portion of the superior border forms
the coracoid process. The pectoralis minor, coracobrachialis, and short head of
the biceps insert into the coracoid process. The pectoralis minor tilts the scapula
anteriorly (20, 39).
The glenoid forms a shallow dish, which acts as the scapular portion of the
glenohumeral joint. The long head of the biceps and the long head of the triceps
arise from the supraglenoid and infraglenoid tubercles, respectively (3, 20).
The medial border of the scapula is thickened to provide attachment for
the levator scapulae, rhomboid minor, and rhomboid major. Together, the levator
and rhomboids act to adduct, elevate, and downwardly rotate the scapula (20,
39). The inferior angle is rounded and thicker for attachment of three strong
muscles: the lower portion of the rhomboid major, the lower digitations of the
serratus anterior, and the teres major (3, 20).
The superior border of the scapula is without any muscular attachment.
Since there are no stresses applied to the superior border via muscular attachment,
the bone is thin and sharp (3).
Smooth gliding of the scapula over the irregular thorax is maintained by
the tissues interposed between them. The costal aspect of the scapula is covered
by the subscapularis muscle and the serratus anterior. The subscapularis arises
from the subscapular fossa and inserts into the lesser tubercle of the humerus
(3, 20). The serratus anterior originates from the upper eight or nine ribs via
fleshy digitations and inserts into the costal aspect of the medial border and
inferior angle of the scapula (3, 20, 39). The majority of the serratus inserts on
the inferior angle, making the serratus a strong lateral rotator of the scapula (1,
3, 20, 39). The inferior and superior angles along with the medial border of the
scapula have little soft tissue interposed between them and the ribs; thus, these
Mattocks and Whitney
334
LTOlD
TERES MINOR
NFRASPINATUS
LATISSIMUSS DORSl
TERES MAJOR
Figure 1 -Muscular
attachments on the posterior aspect of the scapula.
areas are poorly cushioned during movements of the scapula (3). Muscular
attachments on the scapula are depicted in Figures 1 and 2.
Subscapularbursae are normally present to reduce friction during movement
of the scapula on the thorax. The infraserratus bursa is situated between the
inferior angle of the scapula and the thoracic wall. The subscapular bursae lie
between the superior-medial angle of the scapula and the upper three ribs (12).
A third bursa, although rare, may be located between the upper digitations of
the serratus and the lateral chest wall (34).
Stability of the scapulothoracicjoint is achieved through articulation of the
scapula and clavicle along with the dynamic stability provided by the axioscapular
muscles. Steindler reported that atmospheric pressure plays an important role in
stabilizing the scapula on the thorax (52).
Biomechanics
The primary function of scapular movement is to provide a stable base for
glenohumeral motion. Additionally, scapular movement maintains an optimal
length-tension relationship for the scapulohumeral muscles and increases the
total range of motion available to the arm (25, 39). Movements of the scapula
include elevation/depression, protractionlretraction, upward and downward rotation, winging, and tipping (39). Elevation is movement of the scapula toward
the head, while depression is translation of the scapula caudally. Protraction is
movement of the scapula away from the midline, and retraction is movement of
the scapula toward midline. Upward rotation is that movement in which the
inferior angle moves laterally and the glenoid is tilted upward. Downward tilting
Snapping Scapula
SHORTHEAD OF BICEPS 8 CORACOBRACHIALIS
I
I
PE,CTORALIS MINOR
ANTERIOR
Figure 2 -Muscular attachments on the anterior aspect of the scapula.
of the glenoid and medial movement of the inferior angle constitute downward
rotation (39).
Scapular winging is a term often used to denote pathological movement
of the scapula; however, a small degree of this movement is necessary for normal
shoulder motion (39). Full scapular protraction moves the scapula anteriorly on
the curved thorax, so that the medial border of the scapula moves away from
the thorax. Scapular tipping is movement of the inferior angle posteriorly and
the glenoid anteriorly around a coronal axis (39). This motion is a very small
movement that occurs as a result of normal movement of the scapula on the
thorax.
In functional activities, movement of the scapula occurs not as a single
motion but as combinations of motions as seen in the normal scapulohumeral
rhythm of flexion or abduction of the arm. During the initial phase of elevation
(60" of flexion or 30" of abduction) movement of the scapula is variable, and
the scapula is said to be seeking a position of stability (17,42, 43). As elevation
continues, increasing amounts of scapular rotation occur, so that the scapula-tohumerus ratio of movement approaches 1:l (13, 15). During the late stages, the
majority of movement again occurs at the glenohumeral joint (13, 15). For the
full motion from beginning to end, 2" of humeral motion occurs for every 1" of
scapular motion. While many researchers dispute specifics of scapulohumeral
rhythm, they generally agree on the 2: 1 ratio for the total range of the movement
(17, 25, 39, 42, 43, 49).
The key to coordinated scapular movement during arm elevation is smooth
upward rotation of the scapula. Scapular upward rotation is powered by the
trapezius and serratus anterior muscles (1, 14, 17, 25, 52). Inman et al. (17)
336
Mattocks and Whitney
described these two muscle groups as forming two separate force couples that
worked synchronously to drive rotation of the scapula. The upper force couple
consists of the upper trapezius, the upper digitations of the serratus, and the
levator scapula. These muscles elevate and upwardly rotate the scapula and
provide "postural suspension" of the shoulder-girdle, especially when the arm
is loaded (3, 24, 52).
The lower force couple consists of the lower trapezius and the lower digitations
of the serratus anterior. These two muscles act together throughout the range of
elevation; however, the serratus anterior is more active in shoulder flexion and the
lower trapezius is more active in shoulder abduction (17, 36, 39).
The middle trapezius and the rhomboids provide controlled stability to the
scapula during upward rotation. Eccentric contraction of these muscles provides
controlled motion of the scapula, as it is guided by the trapezius and serratus (3,
14). The middle trapezius and rhomboids are active during the entire range of
elevation but are more active when elevation is performed in abduction versus
flexion (17, 39, 52).
Although elevation is the only motion for which scapulohumeral rhythm
has been studied (2, 13, 15, 17, 44, 49), it is assumed that all motions of the
upper extremity require a synchronous and coordinated action of the entire shoulder complex. Any alteration of this normal rhythm can result in less than optimal
functioning (39, 51, 57).
Signs and Symptoms
The presentation of snapping scapula or scapular crepitus is highly variable. The
most prominent physical finding is the presence of scapular noise with motion
of the scapula (33-35,46, 58). The scapular noise may be quite audible or may
be detected as crepitus during palpation. The sound may be a single snap or a
series of snapping sounds (33-35). Some patients are able to elicit the noise at
will and have absolutely no pain (35). Pain may or may not be associated
with the scapular sounds (33-35, 37, 55). Some patients present with constant
periscapular pain, while others only have pain with movement (30, 31, 33-35,
41, 58). Deep breathing and lying on the involved scapula have been reported
to be painful in some cases (9). Exquisite tenderness to palpation about the
superior angle and medial border of the scapula is also a common finding (30,
31, 33-35, 46-48, 58).
Range of motion of the shoulder girdle and neck may be full or restricted.
Decreased range of motion may be due to pain, stiffness, and adaptive shortening
of muscles or capsuloligarnentous structures (9, 46, 58).
Neurological signs such as loss of muscle strength, diminished deep tendon
reflexes, or altered sensation are not part of the presentation of snapping scapula
syndrome (7,8). However, it is not uncommon for patients to experience referred
pain into the neck, shoulder, and ulnar side of the forearm and hand (7, 8, 30,
31, 35, 47,48, 54).
Etiology
As mentioned previously, multiple etiologies of scapular noise have been reported
Snapping Scapula
337
changes in the soft tissues (9,16,33-35,50,58), (b) snapping due to incongruence
of the bony structures (33-35,41,46,53, 5 3 , and (c) noise of unknown etiology
(33-35, 41, 46, 53, 55) (Table 1).
Soft Tissue Changes
Soft tissue changes may include inflamed or adventitious bursae, elastofibroma,
and pathologica~changes in the tissues. Sisto and Jobe reported on four professional baseball players who developed painful scapulothoracic bursitis at the
inferior angle of the scapula. In these cases there was a palpable mass at the
inferior angle, pain during the early and late cocking phases of pitching, and an
audible click during flexion and extension movements of the shoulder (50).
Additionally, Milch reported a case in which imaging studies were negative, but
a thickened bursa1 formation was discovered at the superior angle during surgery.
Laboratory studies of this specimen showed evidence of chronic inflammation
and fibrosis (33).
Haney presented three interesting cases of subscapular elastofibroma that
caused scapular snapping (16). Elastofibromais a nonneoplastic soft tissue growth
that appears to be a response to repetitive microtrauma (16). The elastofibromas
were located beneath the inferior angle of the scapula. Two of these cases
responded to conservative treatment, while the third required surgical removal
of the mass. The author suggested that the elastofibroma and scapulothoracic
bursa described by Sisto and Jobe (50) both represent reactive changes to repetitive
stresses and may be related (16).
Milch hypothesized that scapular crepitus may result from a condition
similar to tendinitis crepitans. A specimen from a resection by Milch showed
evidence of chronic inflammation and fibrosis of the subscapularis muscle and
the intermuscular fascia (34).
Bony Changes
Changes in the bony structure of the scapulothoracic mechanism may be considered as the second major etiologic grouping. Milch and Burman described an
excessive anterior curvature of the superior border of the scapula as a possible
cause of scapular snapping and pain. The absence of symptoms following the
resection of this area of the scapula provides empirical evidence that this was
the cause of the symptomology (35).
Osteochondroma,a fibrocartilaginousnodule or tumor on the costal surface
of the scapula, has been proposed as a cause of scapular snapping. Osteochondromas are the most common benign tumors of the scapula (37). In 1870 von
Luschka described an exostosis, most likely an osteochondroma, on the superior
angle of the scapula causing scapular snapping. Since that time any bony outgrowth of that area has been termed a Luschka's tubercle. Actually there may
be multiple causes for the so-called Luschka's tubercle. Bateman proposed that
repetitive, forceful motions of the shoulder can cause periosteal microtears that
lead to bony projections at the site where the muscle was avulsed from the
scapula (4). Single episodes of trauma to the shoulder region causing subperiosteal
hemorrhage and secondary ossification have been suggested as possible etiologies
(53). Richards and McKee hypothesized that bony projections at the superior
Mattocks and Whitney
338
angle of the scapula are anatomical variants that only become symptomatic
following some type of trauma (46). Miscellaneous causes of scapular snapping
due to bony abnormalities are listed in Table 1.
Unknown Etiology
Several authors have reported cases in which no obvious pathology was found
to explain the symptomology (9, 56). Poor posture with sagging of the scapula
has been postulated to be a cause of snapping scapula (9,58). Cameron suggested
that in cases that do not demonstrate an obvious cause, the etiology may be one
of abnormal posture (9). Wood and Verska observed that pain and snapping
could be relieved by passively elevating the scapula into a more normal position
(58). Scapular crepitus has been reported to be common in piano players, dressmakers, bakers, machine operators, typists, long-haul drivers, and other occupations that may induce poor posture (30, 31, 34).
Cameron reported three cases in which there were no radiological findings
or pathological findings at surgery. Despite the absence of findings, resection of
2 cm of the medial scapular border relieved all symptoms completely (9). Cameron
hypothesized that the surgery caused the scapula to be pulled into its more normal
resting position, thus relieving the symptoms (9).
The medical literature contains several reports of an entity termed scapulocostal syndrome. The hallmark signs of this syndrome are tenderness at the
superior medial angle of the scapula and periscapular pain that may radiate into
the arm or base of the neck (30, 31,47,48, 54). The etiologic factors commonly
reported for this entity include poor posture, trauma, and occupational stresses
(7, 8, 30, 31, 47, 48). Symptoms are often ameliorated with injection, thermal
modalities, correction of postural faults, and appropriate exercise (7, 8, 30, 31,
47, 48, 54).
The similarities between scapulocostal syndrome and snapping scapula of
unknown etiology suggest that their pathology and mechanism of injury may be
the same. Turek even suggested that snapping scapula and scapulocostal syndrome
both result from scapulothoracic bursitis, specifically bursitis of the bursa at the
superior angle of the scapula (55). Several authors link scapulocostal syndrome
to thoracic outlet syndrome and the myofascial pain syndromes (7, 8, 19, 30,
31, 55, 58). Milch stated that scapular crepitus from soft tissue involvement is
likely to be scapulocostal syndrome (34). A key finding linked to all of these
syndromes is poor posture of the shoulder and neck (7-9, 30,31,33-35,47,48,
54, 56, 58).
Differential Diagnosis
As part of the examination it is necessary to rule out the possibility that the scapular
pain is referred from another anatomic site. The two most common areas that
refer pain to the scapular area are the cervical spine and the glenohumeral joint.
Inflammation of cervical nerve roots 5,6, and 7 can cause pain in the scapular area
(6-8, 27, 37, 38). Electrodiagnostic and imaging studies are useful in ruling out
cervical spine pathology as a source of scapular pain (37, 38).
Neer stated that pathology of the glenohumeral joint is the most common
cause of scapular pain (37). Any condition that alters glenohumeral function can
Snapping Scapula
339
alter normal scapulohumeral rhythm, causing increased stress on the scapular
muscles. Specifically, shoulder instability has been associated with scapular pain
and dysfunction (37). Shoulder instability may be hard to diagnose, and the
differential depends on a careful history and physical exam (18, 37).
It is important to acknowledge that shoulder pain may be referred from
visceral organs including the diaphragm, heart, lungs; spleen, liver, and pancreas
(6,7). Pathology of the scapular area can refer pain into the head, neck, shoulder,
arm,and hand (6-8,30, 31,54).
The differential diagnosis attempts to determine the true cause of scapular
noise and pain. In cases of bony abnormalities, imaging studies aid in the diagnosis
of snapping scapula of bony origin. X rays taken from anterior to posterior and
various oblique views are often necessary to pinpoint the bony protuberance (34).
~dditionallitransverse computerized tomography (CT) scans are valuable in
determining asymmetric prominence of the superior medial angle of the scapula
(46) (Figure 3). In cases of palpable masses around the scapula that give rise to
noise and pain, excisional or needle biopsy is recommended to rule out neoplastic
disease (16). Unless the mass shows signs of neoplastic disease such as aggressive
growth, severe pain, or adhesion to the overlying skin, the condition is best
managed as an overuse-type injury (16).
The majority of cases of scapular snapping or crepitus do not present with
any bony abnormality (9, 58). When there is no obvious bony abnormality, the
physician makes a diagnosis based on his or her experience and by ruling out
other possible causes. Milch reported that careful palpation enabled the examiner
to localize the site of pathology (33). The ability to eliminate or greatly reduce
the pain with an injection of an anesthetic or steroid is also helpful in determining
the anatomic site of pathology (56).
Figure 3 - CT scan demonstrating the relationship of the scapula on the thorax.
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Snapping Scapula
341
of other soft tissue pathology. It is imperative that perpetuating factors be eliminated or sufficiently minimized. These factors could include postural stresses
and occupational and recreational activities. Faulty posturing during sitting, standing, and occupational activities can overwork the musculature, causing painful
mnscle spasm (7, 8, 54). It is essential that the ergonomics of the workplace be
corrected to ensure correct alignment of the body. Relative rest from repetitive
activities that aggravate the condition is important.
Habitual posturing in poor alignment may lead to adaptive changes in the
muscle and connective tissue that will need to be corrected (22). Muscles that have
adaptively shortened will need to be stretched to normal length. Contract-relax
stretching techniques along with patient self-stretching are appropriate (22). Muscles that exhibit stretch weakness will need to be strengthened in order to hold
the body in more normal alignment (Table 2). Additionally, it is not enough to
simply strengthen the muscles; it is necessary to reeducate the muscles to statically
support the body. A soft figure eight harness has been reported to be beneficial
in relieving acute symptoms of scapular crepitus and in assisting with postural
retraining (20, 30, 32, 34).
Because motion tends to cause pain, noise, and irritation it is appropriate to
begin strengthening activities with isometrics. Isometrics are advantageous in this
situation because they can be performed in pain-free positions and irritating movements are avoided. The wall-standingpostural exercise described by Kendall (Figure
4) is appropriate because it helps to retrain the sense of correct postural alignment
and requires sustained isometric contraction of the scapular retractors and thoracic
extensors (20). Additional exercises to strengthen the scapular rotators can be
modifications of classic manual muscle test positions (Figures 5 and 6).
An EMG study by Mosley et al. also provides information concerning
exercises for optimal muscle activity of the scapular rotators (36). Four exercises
were identified as core exercises for the scapular rotators: scaption (scapular
plane arm elevation), rowing, push-ups with a plus, and press-ups. These were
found to be optimal exercises for activating the muscles that stabilize and move
the scapula (Figures 7-10).
Closed kinetic chain exercises for the upper extremity promotejoint stability
without introducing excessive movement to the scapulothoracicjoint. Therefore,
Table 2 Muscles Exhibiting Adaptive Shortening or Stretch Weakness Due to
Postural Abnormalities (20, 22)
Muscles
Adaptive shortening
Stretch weakness
Pectoralis major, pectoralis minor, upper trapezius, stemocleidomastoid, scalenes, levator scapulae, serratus anterior,
latissimus dorsi, suboccipital muscles
Rhomboid major, rhomboid minor, middle trapezius, lower
trapezius, thoracic erector spinae, lower cervical spinal extensors, cervical spine extensors
342
Mattocks and Whitney
Figure 4 - Wall-standing postural exercise. Stand with heels 2-3 in. from the wall
with trunk and head against the wall. Place the back of the hands and elbows against
the wall. While maintaining this position slowly raise and lower the arms. This
strengthens the lower and middle trapezius muscle.
closed chain exercises may be effective strengthening and retraining activities
(Figures 11 and 12).
As strength improves and symptoms decrease, the exercise program can
gradually be increased. Multiple-positionisometrics lead into full-range strengthening activities. Repetitions and resistance should be progressed cautiously to prevent
any exacerbation of symptoms. The scapulothoracic muscles' primary function is
static posturing of the shoulder girdle, and they are not typically required to produce
high force levels (18,24,52,54). Because the scapulothoracic muscles are postural
muscles, it is essential to retrain the endurance of these muscles. This is best
accomplished through low-weighthigh-repetition exercise programs (18,22). Suggested strengthening exercises are summarized in Table 3.
Neuromuscular retraining is an essential component in the rehabilitation
plan. Initially, EMG biofeedback may be useful to assist the patient in firing the
correct muscles during postural retraining. Activities must be included that promote normal scapulohumeral rhythm during arm activities. Such activities may
include upper extremity proprioceptive neuromuscular facilitation (PNF) diagonals with resistance applied manually or with free weights or surgical tubing
(Figure 13). Additionally, functional activities related to the client's sports or
occupational tasks should be part of the overall program.
Late-stage rehabilitation should include eccentric exercise. Eccentric contractions can transmit increased tension to the musculotendinous unit and may
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344
Mattocks and Whitney
Figure 7 - Scapular plane arm elevation (scaption) for strengthening the upper
trapezius and serratus anterior muscles.
Figure 8 -Press-up exercise used to strengthen the pectoralis minor.
Snapping Scapula
345
Figure 9 - Push-up with a plus, for strengthening the serratus anterior and pectoralis
minor muscles. Initially this exercise may be performed against a wall as shown. As
strength increases the difficulty may be increased by performing the exercise on the
floor against body weight.
induce maturation of strong tissue (10). Additionally, eccentric contractions of
the scapular muscles are required during functional activities, such as lowering
an object from a height. Pertinent aspects of rehabilitation and exercise progression are summarized in Figure 14.
Throughout the stages of rehabilitation, pain and inflammation should guide
treatment. Modalities to reduce and control inflammation and pain are appropriate
especially during early stages but may be used throughout the treatment period.
In acute conditions cold modalities such as cold packs and ice massage are
preferred for their ability to decrease pain and inflammation (32, 45). Subacute
and chronic conditions may respond best to heat modalities. Heat can induce
relaxation, decrease pain and muscle guarding, and increase tissue extensibility
(32,45). Ultrasound has been reported to be helpful in decreasing muscle spasm,
trigger points, and associated pain (32, 45, 54). Electrotherapy can be used for
pain control as well as reeducation of the scapular muscles (45).
Surgical Treatment
Surgical intervention can be considered in cases that demonstrate obvious bony
deformities or osteochondromas, or those resistant to conservative treatment (34,
41,46, 50). The superomedial angle is the most common site of pathology, and
surgical technique describes resection of this area (33-35, 41, 46, 53, 56, 58).
Milch believed that in cases without bony abnormality, palpating for crepitus
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Snapping Scapula
347
Figure 11 - Closed chain exercise on the Gymnastic Ball to promote scapular stability.
would indicate the area of scapula to be resected (34). Surgical intervention in
cases without bony pathology is less well documented. Three cases of snapping
scapula without obvious cause, reported by Cameron, were completely relieved
of their symptoms by surgical resection of 1-2 cm of the entire medial border
of the scapula. The surgical technique was not described in the article (9).
Resection of the superomedial angle is performed through an oblique incision over the superior angle of the scapula. The trapezius is split in the direction of
the fibers. The rhomboids, serratus anterior, and supraspinatus are subperiosteally
dissected from the scapula. A triangular piece of scapula with 4- to 5-cm borders
is removed from the superior angle. The detached muscles are reapproximated
and the site is closed in layers (46).
Review of the surgical cases presented in the English medical literature
reveals a very high success rate for this surgery (9, 33-35, 41,46, 53, 58). The
majority of cases presented involved bony abnormality of the scapula, and only
two reports dealt with surgical intervention in cases without obvious bony pathology (9, 58). In general, snapping scapula of soft tissue etiology is best managed
conservatively,and in cases of obvious bony pathology surgery should be considered (33-35, 41, 46, 53).
Summary
Scapular pain and noise may result from any number of pathologies about the
shoulder and neck. A careful history and examination most often will reveal an
Mattocks and Whitney
348
Figure 12 -Exercise
tivity.
on the Pro-fitter provides another means of closed chain ac-
Table 3 Suggested Strengthening Exercises (18, 20,36)
Muscle
Exercise
Upper trapezius
Middle trapezius
Rowing, shrugs, scaption
Horizontal abduction (neutral rotation),
rowing, MMT position, wall standing
exercise
Rowing, wall standing exercise, abduction
Rowing, shrugs, horizontal abduction
Horizontal abduction, shoulder retractions
Shoulder flexion, military press, scaption,
push-ups with a plus, serratus punch, end
range flexion in prone
Press-ups, push ups
Lower trapezius
Levator scapulae
Rhomboids
Serratus anterior
Pectoralis minor
Note. Resistance can be added by means of free weights, elastic tubing, machines, isokinetics, and manual resistance.
Snapping Scapula
349
Figure 13 - Strengthening with elastic resistance to PNF diagonals.
POSTURAL RETRAINING
t
EDUCATE
STRETCHING & ROM
Scapular Mobility
-G-H Capsule
-Scapula-Humeral Muscles
-Axioscapular Muscles
-Axiohumeral Muscles
STRENGTHEN
-Postural Alignment
-Sitting Postures
-Standing Postures
-Work Postures
-Recreational Actlvity
-Figure Eight Brace
-Scapular Taping
+
I
-Manual Resistance1
in Painfree Range
-Closed Chain Stability
-Isotonics IPREs
-Concentrlc/Eccentric
-Piyometric
Scapular Mobilization
-G-H Mobllizatlon
-Contract-RelaxMold-Relax Stretching
-Self-Stretching (Prolonged)
J
\
DYNAMIC STRENGTH-MUSCLE
-1sokinetlcs
-Plyometrics
-Hlgh Speed Activities
with Elastic Tubing
4
'
-Scapula-Humeral
-Axioscapular
-Axio-Humeral
-Thoracic Extensors
RE-EDUCATION
-PNF
-8lofeedback
-Visualization
J
FUNCTIONAL RETRAINING
(Slow
(Light
(Low
-+
-+
-+
Fast)
Heavy)
High RepetiUons)
Figure 14 -Schematic diagram of the components of the rehabilitation program
for scapular dysfunction.
Mattocks and Whitney
350
anatomic cause for the pain. In cases that d o not present with an obvious cause,
careful attention should be directed toward posture, strength, and endurance
of the scapular muscles. Guidelines have been presented for the conservative
management of soft tissue causes of scapular pain. Future research that determines
the efficacy of conservative treatment as outlined for patients with soft tissue
pathology should be performed.
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Author Note
This paper was submitted by L. Mattocks as a partial fulfillment of the requirements
of the master's of science degree at the University of Pittsburgh.