Phil Page reviews a journal article regarding scapular position and thoracic outlet syndrome. Interesting find that a lower scapula tends to be correlated with TOS. This obviously makes sense. I would actually take this a step further myself and include muscles that attach to the clavicle that keep the clavicle depressed towards the rib cage, such as the subclavius.
Upcoming Courses to Consider
There are a bunch of interesting CEU courses coming your way around the country from friends of mine.