Snapping Scapula Syndrome: Grating Sensation of the Scapulothoracic Joint with Possible Pain

Posted on 25 Feb 2012 21:20

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Snapping Scapula syndrome is a snapping, grinding, or popping sensation or sound with scapulothoracic movement. Although pain with shoulder movement is usually present, some may have no pain. It is also sometimes referred to as scapulothoracic bursitis, scapulothoracic crepitus, superior scapula syndrome, scapulocostal syndrome, retroscapular creaking, washboard syndrome, rolling scapula, and grating scapula. It was described by Boinet as early as 1867, who presented the case of a 10 year old who had discomfort with scapula movement.

When the scapula moves during upper extremity movement, it must glide along the underlying ribs that form the thoracic wall. It is normal for there to be friction between the scapula and the chest wall at these times. This friction is cushioned by a several subscapular bursae, the serratus anterior and subscapularis muscles, except for the superior and inferior scapular angles and the medial border, which are poorly cushioned and vulnerable to mechanical abrasion from any abnormal surface growths.

Normal scapular gliding and friction usually causes no problems or symptoms. Snapping scapula, on the other hand, is associated with a louder and palpable (tactile-acoustic) popping, grating or snapping sound that may have pathologic origins, resulting from something unusual existing between the undersurface of the scapula and the thoracic wall. The severity of the snapping noises may help indicate whether the problem is pathologic.

It is just as likely, if not more likely, that the problem is caused by irritation of the bursa due to mechanical trauma, most often in the upper or lower tip nearest the spine. Scar tissue and fluid build up in the bursa affect the gliding motion of the scapula over the thorax. This condition is known as scapular bursitis. Like all bursitis, this will be very painful, regardless if there is crepitus present.

Otherwise, the muscles underneath the scapula may have become weak and small for some reason, which will cause the scapula to ride more closely to the ribs, bumping or rubbing on them and thereby producing the snapping sensation.

A previously fractured scapula or rib bone that failed to line up properly during healing (malunion) may form a bumpy ridge that causes the crepitus. Also, any abnormal shape, like a bump, or unusual curve on the upper edge of the scapula near the spine could be responsible. Many of these possibilities are listed below.

Resources seem to disagree as to whether snapping scapula, as a clinical entity, should be considered to always be accompanied by pain. Some experts think that scapular crepitus alone is not enough for the diagnosis of this "syndrome" while others say that pain may or may not be present. It is not a very common condition in the general population but occurs more often in athletes (especially overhead throwing athletes), the military, and workers.


Sometimes the cause of snapping scapula is unknown and can occur spontaneously. Although the sensation may be worrisome, it does not necessarily pose any problems. It is possible that the problem may relate to a previous surgery to the shoulder girdle but the cause is usually abnormal movement patterns of the scapula, which allows the bony edge of the scapula to make contact with the ribs underneath, producing the grating and popping sensation. A one-time trauma may lead to this, or ongoing repetitive trauma to the muscles, causing scarring amd swelling of the subscapular soft-tissue or bursa. In general, causes can be divided into bony and soft tissue problems:

  • Changes in the surface of the bone of the scapula
  • Changes in the surface of the ribs.
  • A tumor of the scapula, such as osteochondroma (rare but most common scapular tumor)
  • Osteogenic sarcoma
  • Luschka's tubercle (exostosis, or the formation of new bone on the scapula's surface)
  • Sprengel's deformity (High scapula or Congential high scapula)
  • Curling of vertebral border
  • Old scapula fracture that improperly healed (fracture malunion)
  • Old rib fracture that improperly healed
  • Abnormal angle or curvature in the superior scapula
  • Soft tissue tumers
  • Repetitive use injury to the periosteum of scapula
  • Bone spurs along the medial portion of scapula where the muscles attach
  • Inflammation of the subscapular bursae
  • Muscle atrophy from disease or nerve injury and less soft tissue between scapula and ribs
  • Myofibrosis of surrounding muscles
  • Elastofibroma from repetitive microtrauma (a soft tissue growth) - RARE
  • Scoliosis
  • Thoracic kyphosis

Scapular Bursitis Versus Snapping Scapula Syndrome

Scapular bursitis, also called scapulathoracic bursitis is often referred to as if it is the same thing as snapping scapula syndrome. As seen above, scapular crepitus can have many different causes. Scapular bursitis, discussed further below, is inflammation of the scapular bursae caused by trauma or overuse from athletic activities or work. It is particularly common in overhead athletes or those performing overhead work. Bursitis can be associated with crepitus of the scapula. Both can be caused by trauma, overuse, shoulder joint dysfunction, bony abnormalities, muscle atrophy or fibrosis, and idiopathic (unknown) causes.6 However, scapular bursitis is sometimes used as a catchall for any scapular crepitus associated with soft-tissue causes. There are six bursae associated with the scapula, two small and four large. These bursa all the scapula to glide more smoothly along the chest wall.


The main symptoms and signs of snapping scapula syndrome are aubible and palpable grinding and snapping of the scapula (crepitus) during shoulder girdle movements and this sensation is most often felt in the top inside part (superomedial edge) of the scapula. This is sometimes accompanied by pain in the scapulothoracic area, most notably along the superior medial border of the scapula. You may be able to easily recreate the feeling with voluntary movement and some people have a feeling that their shoulder is "jumping out of place" or giving way. This may lead some to think that they their shoulder is dislocating.


Treatment is usually conservative and rarely requires surgery. Many times, all that is needed is a bit of reassurance that the sensations, when not accompanied by pain, are not all that serious. When pain is present, analgesics are helpful and heat are helpful. Corticosteroid injections into the area of pain may be helpful, as in the case of scapular bursitis, although great care must be taken to avoid possible complications. Sometimes the scapula is taped to facilitate proper posture and positioning. Physical therapy to address abnormal neuromuscular patterns, known as scapular dyskinesis.

Scapular dyskinesis is an alteration in the position of the scapula and the patterns of scapular movement in relation to the thoracic cage. This is most commonly caused by abnormal muscle activation and coordination with elevation and rotation. The scapula's three articulations are known as the shoulder girdle. These joints are the sternoclavicular (SC), acromioclavicular joint (AC), and the scapulothoracic joint. Proper movement of the shoulder joint itself (the glenohumeral joint) cannot occur without an appropriate accompanying movement of the shoulder girdle. When these shoulder girdle movements get "out of whack," scapular dyskinesis has occured.1 It should be noted, however, that patients with scapular dyskinesis will not usually complain of scapular problems, but of glenohumeral joint pain.

Shoulder range of motion is usually a priority, along with strengthening the scapular stabilizers so that the scapula becomes positioned properly and moves properly with glenohumeral joint movement.

Postural distortions such as forward head wit excessive cervical lordosis, thoracic kyphosis, or scoliosis should be evaluated and corrected, when possible. Tightness, weakness, and/or atrophy may be found in the trapezius, latissimus dorsi, subscapularis and other rotator cuff muscles, serratus anterior, rhomboids, deltoids, levator scapulae and also the rotator cuff muscles. A program of rehabilitation to improve scapular stability and scapulohumeral rhythm should be undertaken. This training should emphasize movement patterns rather than isolated muscles, although some exercises may be used to activate certain muscles, such as the serratus anterior. Such training may include, but is not limited to, such exercises as:

Trigger Points and Myofascial Release

Myofascial release of the periscapular musculature may be helpful such as deep friction massage. Trigger point therapy to release trigger points in the associated periscapular and other muscles may also be helpful, especially in the case of pain, where referred pain from trigger points may mix with pain in superomedial scapular region. Levator scapulae trigger points, in particular, refer pain to this region, as well as to the back of the shoulder. Other trigger points include TrP's in the scalenes, rhomboids, and to a lesser extent the supraspinatus and infraspinatus. According to Travell and Simons7, snapping and grinding during scapular movement may be an due to trigger points in the rhomboid muscle, specifically, though the authors provide no explanation as to why this should be true.


As above, surgery is rarely necessary but when structural abnormalities are present, such as exostosis, a surgical resection may be helpful. Bony prominences, once documented, may be removed, whether of the scapula or ribs and a thickened bursa may be excised as well. Even if there is no known bony deformity of the medial scapular edge, bony resections of the area have reported success in relieving symptoms. These surgeries have traditionally been open but endoscopic surgery has also been successful.

1. Hammer, Warren I. Soft-tissue Examination and Treatment by Manual Methods. Sudbury, MA: Jones and Bartlett Pub., 2007.
2. Hutson, Michael A., and Cathy Speed. Sports Injuries. Oxford [u.a.: Oxford Univ., 2011. 248.
3. McFarland, Edward G., and Tae Kyun. Kim. Examination of the Shoulder: The Complete Guide. New York: Thieme, 2006. 61.
4. Iannotti, Joseph P., and Gerald R. Williams. Disorders of the Shoulder: Diagnosis & Management. Philadelphia: Lippincott Williams & Wilkins, 2007. 1077.
5. Aalderink, Kristopher, and Brian Wolf. "Scapular Osteochondroma Treated With Arthroscopic Excision Using Prone Positioning." The American Journal of Orthopedics 2010;39(2):E11-E14 (2010).
6. Conduah, A. H., C. L. Baker, and C. L. Baker. "Clinical Management of Scapulothoracic Bursitis and the Snapping Scapula." Sports Health: A Multidisciplinary Approach 2.2 (2010): 147-55.
7. Simons, David G., Janet G. Travell, Lois S. Simons, and Janet G. Travell. Travell & Simons' Myofascial Pain and Dysfunction: the Trigger Point Manual. Baltimore: Williams & Wilkins, 1999.
8. "Scapular Bursitis." PedOrtho. Web. 24 Feb. 2012. <>.


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This page created 25 Feb 2012 21:20
Last updated 23 Jul 2016 01:02

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