Don't Wreck Your Rotator
Many people suffer from structurally shifted shoulder joints. It’s easy to understand why this could happen. The shoulder’s only bony attachment is where your clavicle (collar bone) attaches to your sternum. Every other attachment of the shoulder involves proper muscle tension of the rotator cuff muscles and the labrum. There are already many articles that focus on supraspinatus tendinopathy (the most common rotator cuff muscle that is damaged) and how the other rotator cuff muscles can become dysfunctional and/or damaged. Instead, today, I would like to discuss a different perspective on why so many people, from high school athletes to 80 year old men, suffer from structurally shifted shoulders.
It all starts with the small connections (called the dentate ligaments) that attach the top of the spinal cord to atlas (the top bone of the spine). The purpose of these dentate ligaments is to anchor the spinal cord in place so that it does not move so much as to hit the bones that make up the neural canal. When atlas is structurally aligned, there is no stress placed upon the base of the brainstem and top of the spinal cord. When it is shifted, however, it causes disturbances in the tracts of the spinal cord (which are what directly set the resting muscle tone of the spinal postural muscles) as well as the brainstem, which functions to control our sense of balance. This structural misalignment at atlas results in an imbalance between the left and right side of the shoulder girdle muscles, with the most obvious sign being a raised shoulder on one side.
This extra tension would lead to a chronic stress being placed on, at least, every joint that rotator cuff muscle attaches to and crosses. Let’s look at the supraspinatus. It starts on the top of the scapula, crosses the acromioclavicular (AC) joint, as well as the glenohumeral joint (shoulder), and inserts into the top/side of the humerus. A structural shift at Atlas puts stress into the cord, causing an imbalance between the tension in the left and right supraspinatus muscle, with the right supraspinatus firing at a higher rate, causing an increase in tension. The 35 year old person has a higher shoulder on the right (the supraspinatus pulls it higher), their AC joint is stressed with greater pressure in the top of the joint then the bottom, and the humerus is shifted superiorly. For a few days to weeks, this is not that big of a deal. The person has some general shoulder soreness, and they have some shoulder pain at the end when going through a full range of motion. Let us fast forward 6 months to a year from the initial Atlas misalignment, and resulting Neuromuscular Imbalance. Now the person has been having sharp pain when abducting their arm above 20 degrees, because the supraspinatus tendon has been rubbing against the acromion process, and they have general dull soreness constantly in the shoulder, because the tendon as well as bursa are inflamed. They also have reduced range of motion of abduction of the shoulder (the main action of the supraspinatus) and the entire scapula has started to externally rotate, or wing. As this process goes on, range of motion continues to decrease, and more and more compensations affect the kinetic chain of the extremity, from the area inbetween the shoulder blades, all the way down to the elbow and wrist.
Is this the only reason that a shoulder can have dysfunction? Certainly not. Ask yourself this, is it reasonable to think that there must be a reason why there is such a high percentage of shoulder MRIs that show supraspinatus tendinopathy, and enough evidence to justify rotator cuff surgery in many individuals? If you know someone who has been to specialists, and even after conservative treatment (such as laser therapy, electric stim, ultrasound, physical therapy) or invasive treatment (pain meds, manipulation under anesthesia, surgery) consider that their may be an underlying cause that is not being addressed, a structural shift.