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So, we see that movement of the arm/ humerus is strongly dependent upon coupled movement of the scapula. But, as we have mentioned, the clavicle must be included in this conversation as well. There is a rhythm between scapular movement and clavicular movement. In fact, much of the movement of the scapula at the ScC joint is driven by movement of the clavicle. In our example of scapular upward rotation of 60 degrees to accompany full humeral abduction, half of that scapular upward rotation occurs because the clavicle elevates at the sternoclavicular (SC) joint relative to the sternum, and as the clavicle elevates, the scapula is brought along with it such that it changes its position relative to the rib cage. We could say that the scapula passively "goes along for the ride." So, even though there are muscles that can actively move the scapula into upward rotation, the scapula can also be passively moved into upward rotation by accompanying elevation of the clavicle. For example, during the first 90 degrees of arm abduction, 60 degrees are due to GH joint humeral motion, and 30 degrees would be due to scapular upward rotation at the ScC joint. Of these 30 degrees of scapular upward rotation, 25 degrees occur as the scapula is passively moved by clavicular motion (Image 4A). There are another 5 degrees of scapular upward rotation created by the scapula actively upwardly rotating relative to the clavicle at the acromioclavicular (AC) joint (Image 4B) (see Scaption sidebar, page 54). So, the question might be: Is this just anatomy geek information, or is there an application for manual therapists and movement professionals? To answer this question, let's look at a potential case study. POTENTIAL CASE STUDY A client presents with decreased abduction range of motion of the right arm. How do we perform our assessment? If we L i s te n to T h e A B M P Po d c a s t a t a b m p.co m /p o d c a s t s o r w h e reve r yo u a cce s s yo u r favo r i te p o d c a s t s 53 The scapula can also actively upwardly rotate relative to the clavicle at the AC joint. Dr. Joe Muscolino. Kinesiology—The Skeletal System and Muscle Function, 3rd ed. (Elsevier, 2017). When the clavicle elevates, the scapula moves with the clavicle and is passively upwardly rotated. Dr. Joe Muscolino. Artwork by Giovanni Rimasti. †A †B Clavicle Acromion process of the scapula AC joint Elevation Upward rotation 25° Clavicle AC joint Acromion process of the scapula Upward rotation