this question is a general one but knowing the guidelines for investigating about this joint is so complicating and I need to know about guidelines, as we know the shoulder is a complex joint and the functional movements are matter for me in the daily process of human life or in specific exercising (the sports are using more movements of this joint in upper head position) but the joints I want to know is GJ (glenohumeral joint) and SJ (scapulothoracic joint) in shoulder complex so i will glad to hear your answers and your suggestions.