Involvement of the anterior portion of the subacromial-subdeltoid bursa in the painful shoulder.

OBJECTIVE. The purpose of our study was to verify that increased widening of the anterior portion of the subacromial-subdeltoid bursa is associated with anteromedial shoulder pain. MATERIALS AND METHODS. Bursography, sonography, and CT were performed in six cadaver shoulders and compared with anatomic sections in neutral position and while the humerus was extended and internally rotated. For the clinical study, the width of the anterior portion of the bursa was measured in both positions in both shoulders of 27 patients referred because of shoulder pain and in eight asymptomatic volunteers. Pain was coded as absent, experienced in the anteromedial portion of the shoulder, or experienced elsewhere but not anteromedially, and we compared the pain scores between shoulder positions. RESULTS. In all cadaver shoulders, when compared with CT scans and anatomic sections, sonography showed the morphology of the bursa, its relationships with surrounding structures, and morphologic changes associated with position. In volunteers, the mean width of the bursa was 0.74 +/- 0.05 and 0.93 +/- 0.09 mm (p = 0.013), respectively, in neutral and stress position. In patients, the same values were 0.70 +/- 0.07 and 0.81 +/- 0.14 mm (P = 0.286) in the asymptomatic side and 1.20 +/- 0.11 and 1.75 +/- 0.23 mm (p < 0.001) in the symptomatic side, respectively. The bursa was wider in patients experiencing pain anteromedially than in those who experienced pain elsewhere and volunteers (p = 0.002 and < 0.001, respectively), and the bursa was wider in symptomatic shoulders than in asymptomatic shoulders (P < 0.001). CONCLUSION. Widening of the anterior portion of the subacromial-subdeltoid bursa is associated with anteromedial shoulder pain and the clinical syndrome of coracoid impingement.