People seldom have any part of this pattern as their primary complaint. When this is a problem, the entire pattern can usually be elicited by pressing up under the collar-bone near the sternum. It is surprisingly intense for a pattern that is seldom a part of their complaint. I usually find this by working the area based on other complaints related to pecs or thoracic outlet syndrome.
A small percentage of people complain about pain along the collar-bone. They trace the pattern along the collar-bone just as shown in the illustration. If subclavius has pulled the collar-bone down onto the subclavian vein, there may be swelling and bluish color in the arm.
The other parts of this pattern are more frequently caused by other trigger points, so this muscle is easy to overlook until the other patterns have been eliminated.
Paget-Schroetter syndrome is a specific form of thoracic outlet syndrome where the subclavian artery moves medially until it is restricted and the arm becomes chronically swollen and bluish. It is more common among athletes that weight lift or play tennis.
In one case, I noticed that the arm was swollen a bluish. The arm turned bright red and the swelling went down when I released the subclavius and pecs, and lifted the collar-bone. Her arm was swollen and bluish again the next morning. I referred her out immediately and she verified the structural anomaly and restricted vein with ultrasound. She resolved the problem by having a section of her rib surgically cut out to provide room for the vein.
When looking at the structures of the thoracic outlet from the front, the first rib is not visible in this illustration as it is covered by the subclavius muscle. You can see how the rib loops around in the illustration below.
Doorway stretches lengthen the subclavius, especially when the elbow is positioned above the shoulder. I talk about them in this post.
Triceps dips, where the shoulder is dropped below the elbow in the low part of the movement, stretches the subclavius and the lateral portion of pectoralis major, which supports the subclavius in pulling the collar bone down.
Subclavius seldom presents as the primary problem but generates intense sensation under static pressure when the trigger point is active. It is easily overlooked but can be a critical piece in resolving thoracic outlet problems. It not only pulls the rib down on the neurovascular bundle but can occlude the bundle, especially the subclavian vein, when it becomes stiff and hypertrophied.
Subclavius is covered by clavicular pectoralis major and can be tedious to work. Mobilizing fixations in the sternoclavicular joint will reduce proprioceptive feedback that perpetuates trigger points in the subclavius.
Tony Preston has a practice in Atlanta, Georgia where he sees clients.
He has written and taught about anatomy, trigger points and cranial therapies since the mid-90s.