In preparation for the Thoracic Synthesis class, I have been pondering the sternoclavicular joint (SCJ). It is a very important joint – often overlooked when we are dealing with shoulder, arm and neck pain and dysfunction.
The SCJ is where the clavicle and sternum meet at the top of your rib cage. It is the only joint that the shoulder girdle has with the axial skeleton. The shoulder girdle otherwise is held onto the body by muscles. The SCJ is held to the sternum by a joint capsule and several ligaments. The is a cartilaginous disk seated within the joint. There is a small muscle called the subclavius muscle that attaches to the underside of the clavicle to the first rib. The subclavian artery, vein and nerves that innervate the arm run between the clavicle and the first rib.
The clavicle is like a strut. In the ideal world, when we move our shoulder, the clavicle moves along for the ride. For instance, when we reach forward, the clavicle moves forward. When we reach up it elevates with the movement.
It is possible to dislocate the SCJ with impact injuries. But what I see and treat more commonly in my practice is restriction of movement. The restriction can be caused by motor vehicle accidents/seatbelt injuries, postural challenges such as rounded shoulders and forward head posture, overuse from forward motions such a cycling, bodywork, cooking. Restriction can also come from constricted or inefficient breathing. If we have shallow breath or are not using our diaphragm muscle efficiently, we tend to use the scalene muscles to lift our ribcage to fill our lungs. (I wrote about this in my last blog.) The scalene muscles attach along the sides of the neck and to the first and second ribs. If we overuse the scalene muscles, they become hypertonic and tend to elevate the first rib causing the space between the first rib and clavicle to narrow and get quite sticky. This can potentially lead to chronic neck pain and Thoracic Outlet Syndrome.
Thoracic Outlet Syndrome is an impingement of the nerves to the arm and the subclavian artery and vein that causes numbing, tingling and weakness into the arm and hand. It can also lead to resistance to moving the shoulders backwards into protraction and shoulder joint restriction.
The short-term solution is releasing the soft tissue that binds the clavicle (that pesky subclavius, the pects, scalenes anterior cervical fascia, and diaphragm, just to name a few) and to mobilize the bones – ribs, clavicle, and spine. The longer-term solution would be to learn to be a more efficient breather by using your diaphragm muscle.
And as daily maintenance, I believe in regularly doing chest opening stretches and exercise.
Think about it…most everything we do as a human is forward – cooking, computer work, bodywork, driving, slumping in our easy chair - so we need to counterbalance that action by strengthening the back (especially lower trap) and stretching the front of the chest. I think it should be part of your everyday routine – like brushing your teeth. Then we stay erect, alert, with good breath, eyes level with the horizon, shoulders free, an expansive wingspan.