**3. Summary**

I had shown some studies about scapular muscles. Summarizing from all studies, we have to discuss the next content during clinical rehabilitation.

First, we do not integrate scapular muscles when thinking about scapular stability. For exam‐ ple, there is the athlete who has poor upper limb ability for endurance to contact by other athlete during sports situation and he/she has scapular instability on these occasions. In this case, we will give him/her the exercise for scapular muscles. However, when the exercise is considered, we have to discuss which muscle especially needs to be strengthened, not gather scapular muscle together. I mean it is important to calculate which direction the external load is absorbed, which direction the athlete have to exert muscle force, and which muscle has the highest muscle activity. The ability for endurance to contact by other athlete must be advanced effectively by strengthening the muscle intensively. We have to consider the impair‐ ment using mechanics about scapulothoracic joint.

Next, it is also important that we examine the responsible joint, glenohumeral joint or scapu‐ lothoracic joint carefully in every direction when a patient has shoulder muscle weakness. Therapists usually judge this in shoulder flexion and abduction, but we must try in shoulder internal rotation, external rotation, horizontal abduction, and horizontal adduction. The tech‐ nique of judgment is to observe scapular instability during shoulder muscle testing. Let us check for sure during muscle testing.

Lastly, we have to understand that it is not true that the subject exerts muscle power at gleno‐ humeral joint after scapular stability. The power on shoulder joint is exhibited by working har‐ moniously with glenohumeral joint and scapulothoracic joint at once. This is very important to think about scapular stability. It is whether scapula stabilizes for external load and weight of the arm. The rehabilitation order that first the scapular position is adjusted and second gle‐ nohumeral joint is exercised is not pertinence. Furthermore, in turn, we have to examine the affect for the motion by assessment to glenohumeral joint and scapulothoracic joint at once.

Taking these points into consideration, it should be clear how the scapular is concerned with the motion. From this, the policy will be definitude and we can provide more effective reha‐ bilitation program. Please make good use for clinical reasoning.
