The shoulder joint is composed of the glenohumeral (GH) joint and the scpulothoracic (ST) joint. The purpose of this study was to identify which joint was contracted in various stiff shoulders: frozen shoulder (FS), rotator cuff tear (RCT), calcific tendinitis (CT), postoperative contracture (fracture), and diabetes mellitus (DM). 49 patients with stiff shoulder (23 males, 26 females, average age: 54 years old): 27 shoulders with FS; 11 with RCT; 6 with CT; 6 with fracture; and 8 with DM were investigated in this study. We recorded ROM of bilateral shoulder joints, pain of passive motion at the sternoclavicular joint, mobility of bilateral scapulas, and measured ROM of the GH and ST joints, with 3DCT. We identified that 27 shoulders with FS had increased motion of the ST joint, hence ROM of GH joints were restricted. The same abnormality of the ST joint was observed in patients with RCT, CT, and fracture groups. However, the ROM of both GH and ST joints were restricted in patients with DM. Increased motion of the scapula was also verified with 3DCT in patients with FS, RCT, CT, and fracture. The GH joint was restricted in all patients, and stiff motion of the ST joint was only observed in 7 of 8 patients with DM.
