Dr. Reed Jarvis, DC | Owner & Chiropractor, The Resilience Lab | Louisville, TN
When people come in with shoulder pain they usually have a diagnosis already. Rotator cuff impingement, tendinopathy, bursitis. The label describes the tissue that's irritated. What it often doesn't describe is why that tissue is irritated in the first place. And without addressing that why, the pain keeps coming back.
The most commonly missed driver of shoulder pain is something most people have never heard of: scapular dyskinesis. It's not a flashy diagnosis. But it's the underlying variable behind a significant portion of the shoulder presentations we see in this office.
What the scapula actually does
The scapula, or shoulder blade, is the foundation of every shoulder movement. It provides the base from which the rotator cuff muscles work, positions the glenoid socket to receive the humeral head, and controls the amount of space available for the rotator cuff tendons as the arm moves overhead. When the scapula moves well and at the right time, the shoulder functions efficiently. When it doesn't, the entire system starts to break down.
The coordinated movement of the scapula and humerus together is called scapulohumeral rhythm. Disruption of that rhythm, when the scapula isn't moving properly or isn't moving at the right time relative to the arm, is what scapular dyskinesis refers to. It's a functional problem, not an inherently painful one. But it directly leads to painful conditions like impingement syndrome, rotator cuff tendinopathy, and bursitis by narrowing the subacromial space and altering the mechanical environment that those structures live in.
Why it happens
Scapular dyskinesis is most commonly caused by muscular imbalance resulting from a combination of weakness, tightness, fatigue, or altered activation. The most common pattern involves overactivity of the anterior muscles, particularly the pectoralis minor and upper trapezius, combined with weakness and inhibition of the posterior stabilizers, the lower trapezius and serratus anterior.
Pectoralis minor tightness tilts the scapula forward, narrowing the subacromial space and positioning the shoulder poorly for overhead movement. Upper trapezius overactivity combined with lower trapezius inhibition leads to a shrugging compensation pattern during arm elevation. Subscapularis trigger points restrict external rotation. Infraspinatus trigger points cause pain that mimics rotator cuff tendinopathy and restrict internal rotation. Each of these patterns creates mechanical disadvantage that leads to impingement and tissue irritation over time.
Forward head posture and thoracic stiffness amplify all of this. A rounded upper back changes the position of the scapula at rest and reduces the ability to achieve proper thoracic extension during overhead movement. The shoulder then compensates, and that compensation is loaded repeatedly with every rep, every throw, every overhead reach.
What a proper shoulder assessment looks like
Shoulder pain warrants a thorough assessment that goes well beyond the shoulder itself. This includes evaluating scapular movement during arm elevation, thoracic mobility, pectoralis minor length, rotator cuff strength and activation patterns, and trigger point patterns throughout the periscapular musculature.
Watching how the scapula moves during weighted flexion and abduction tells us a great deal. Changes in scapular position, winging of the inferior angle, or upward rotation timing that's off all point toward dyskinesis and the muscle imbalances driving it. Cervical and thoracic assessment matters too because dysfunction in the spine directly influences shoulder mechanics.
Imaging has a role but needs to be interpreted carefully. Many people with rotator cuff changes, partial tears, or subacromial narrowing on MRI have no pain at all. The structural finding on the image is not always the clinical driver of the symptoms. The movement assessment tells a more complete story.
How we treat it
Treatment addresses both the painful tissue and the mechanical drivers creating the problem.
Dry needling is one of the most effective tools available for shoulder pain. Trigger points in the rotator cuff and periscapular muscles, particularly the infraspinatus, subscapularis, upper trapezius, and pectoralis minor, respond extremely well to dry needling. A 2021 randomized controlled trial found that dry needling was more effective than sham treatment for improving shoulder range of motion and reducing discomfort in people with rotator cuff issues. Releasing these trigger points directly improves shoulder mechanics by restoring normal muscle tone and reducing the compensatory patterns driving impingement.
Chiropractic adjustments to the thoracic spine and acromioclavicular and glenohumeral joints restore joint mobility and reduce mechanical irritation. Soft tissue work through the pectoralis minor, upper trapezius, and posterior shoulder capsule addresses the restrictions that pull the scapula into a poor position. And progressive rehab rebuilds the lower trapezius, serratus anterior, and rotator cuff activation patterns that keep the shoulder mechanically sound under load.
The combination addresses both the symptom and the structural reason it developed. That's what produces durable results rather than temporary relief.
