| Aim of this study is to find a method to assess the quality of the shoulder muscles and the related functioning of the shoulder. Due to the improvement of diagnostics and the timing of an operation a major improvement of the functional results of the surgical treatment of rheumatoid arthritis is expected. Primary research focuses on the evaluation of the relation between tearing, fat rendering or decrease of muscle mass of the shoulder muscles and on the abnormalities visible on standard X-ray pictures in patients with a rheumatic damage of the shoulder joint. For comparison MRI scans of the shoulder will be used. In addition, the relation between muscle abnormalities visible on the MRI and the functioning of the shoulder measured with an electromagnetic movement detector (Flock of Birds) and a force sensor Amty(R) will be compared. |