How often have I been teaching an overhead movement and said to a student “maintain your rib and mid back alignment- try not to move into extension or flare your ribs open in the front”. But is it possible for us to achieve overhead movement of our arm (shoulder flexion) without concurrent movements at our mid
back and rib cage?
There is a symbiotic relationship between our mid back (thoracic spine), our ribs and our shoulder function
Take a moment to think about the relationship of the shoulder to the ribs and mid back. We learned last week that the connection between the thin, triangular scapula (aka shoulder blade) and our ribs, mid back and adjacent musculature forms the functional (not a true bony articulation) joint known as the scapulothoracic joint.
The scapula and the underlying bony structures of the ribs and mid back are very interrelated. Especially as we come close to the end ranges of our movement (when I was in PT school, we learned the last 10 degrees of overhead arm motion-shoulder flexion- come from thoracic extension). When you watch a client move who has excessive mid back rounding (also known as kyphosis) they are usually limited in their overhead movement. This is because the last few degrees of overhead movement is actually contributed to by our ribs opening in the front, our mid back moving into extension.
This is a nice research study that looked at overhead movement and motion occurring at the mid back and ribs among overhead athletes: overhead reach and accessory motion
If we limit the motion at our mid back and ribs, we ask the shoulder joints to move excessively- to become hypermobile for us, so that we may achieve our full overhead motion.
Because the shoulder joint is already a joint that is challenged in its stability (most of us have too much motion than we can truly control), creating excessive or hyper mobility in this way can be detrimental if practiced over a long period of time.