The pathophysiology of stiff shoulder has not been fully elucidated. The purpose of this study was to clarify scapula and ribs motions in various stiff shoulders: frozen shoulder (FS), rotator cuff tear (RCT), calcific tendinitis (CT), fracture and operation (trauma), and diabetes mellitus (DM). 85 patients with stiff shoulder (36 males, 49 females, average age: 56 years old): 50 shoulders with FS, 15 with RCT, 7 with CT, 10 with fracture, and 13 with DM, were investigated in this study. We recorded ROM of the bilateral shoulder joints, passive motion of the bilateral scapulas, and identified scapulohumeral rhythm (SHR) and motion of ribs in 3DCT. ROM and SHR in the non-affected shoulder were significantly greater than those of the stiff shoulder. Passive scapular motion was severely restricted in patients with DM and FS; however, patients with trauma and CT showed normal scapular motion. Rib depression was observed in patients with DM and FS. Scapular motion was correlated to rib motion. Physical therapy improving scapula and rib motions would lead to a better outcome of FS and DM.
