In recent years, diagnostic ultrasound of the musculoskeletal system (MSUS) has become almost inevitable in everyday clinical practice in rheumatology. Due to the efforts of the European League Against Rheumatism (EULAR), the use of MSUS has significantly increased in Europe. Unfortunately, there are still certain open issues related to MSUS, primarily regarding different ways of interpretation of US findings, the standardization of MSUS findings, and the lack of clear criteria for assessing the competency of sonographers and their certification.