Scapulothoracic bursitis and snapping scapula syndrome
Motion in the scapulathoracic articulation depends on adequate coordination of the concave scapula on the convex thoracic wall by the periscapular musculature. Incongruence, which has several possible causes, such as bony abnormalities, insufficient muscular control and fibrotic bursa may result in painful crepitus during movement.
Scapular bursae can be either anatomic or adventitial, i.e. acquired due to pathological overuse. Anatomic bursae are supposed to facilitate the gliding of the scapula and the thoracic wall relative to eachother, and include the infraserratus bursae, the supraserratus bursa and the scapulatrapezial bursa – with pathology of the supraserratus bursa being most common.
Most patients present with both mechanical as well as non-mechanical symptoms. During history-taking, pain, noise and crepitant sensations during arm movement may be reported. Physical examination should comprise thorough assessment of posture and dynamic function of the cervical and thoracic spine, inspection of the scapulae, palpation around the scapulothoracic articulation and strength testing of the periscapular musculature. Management approaches are initially non-operative: administering of NSAIDs, combined with exercises and activity modifications or eventual steroid and/ or local anesthetic injections into inflamed tissue.