Most adults will experience shoulder pain at some point during their lifetime, and it’s estimated that nearly one-third of adults are affected each year. Among the many possible diagnoses, shoulder impingement syndrome accounts for roughly half of all shoulder pain cases. However, current understanding indicates that shoulder impingement syndrome is not a single diagnosis, but rather a cluster of symptoms that can arise from multiple anatomical and biomechanical factors. The condition is typically classified as either internal or external, depending on where and how the impingement occurs.

The shoulder complex functions as an integrated system of four joints that together allow for an exceptional range of motion. The glenohumeral joint that joins the humerus (upper arm bone) with the glenoid fossa of the scapula is the primary joint responsible for most shoulder movement. It is stabilized by the rotator cuff muscles, labrum, and surrounding ligaments. Under ideal conditions, this joint moves freely to perform tasks like lifting, throwing, or reaching overhead. But when mechanical forces, either within the joint itself or external to it, disrupt that motion, the result may be pain, inflammation, and limited movement. Over time, chronic irritation may lead to scar tissue formation and even degenerative changes.

External impingement occurs when the acromion or coracoacromial ligament compress the rotator cuff during arm elevation. While anatomical variations such as a hooked acromion can predispose some individuals to impingement, the most common contributors are poor scapular control, forward shoulder posture, rotator cuff weakness, or degenerative changes from repetitive overhead activity or aging.

Internal impingement, on the other hand, occurs when the humeral head pinches the rear portion of the rotator cuff between the greater tuberosity and the posterior glenoid rim during high-velocity overhead movements such as throwing or serving. Contributing factors often include posterior capsule tightness, shoulder instability, scapular dyskinesis, excessive external rotation, and repetitive overuse. Internal impingement is more common among younger, athletic, or physically active individuals.

While surgery is occasionally indicated as a first-line intervention in specific cases (such as significant structural damage or full-thickness rotator cuff tears), clinical guidelines overwhelmingly recommend conservative management as the initial approach, with chiropractic care serving an excellent choice! Treatment typically aims to restore normal movement patterns within the shoulder complex through a multimodal approach that may include manual therapies, joint mobilization, specific exercises, physiotherapy modalities, traction, and postural retraining. The goal is to reduce inflammation, restore joint motion, release adhesions, address trigger points, and strengthen weakened muscles.

The good news is that conservative care has a high success rate for both internal and external impingement—especially when treatment begins early—helping most patients recover without the need for surgery.