Shoulder impingement syndrome (SIS) occurs when soft tissues within the shoulder joint are compressed or “pinched.” This mechanical irritation happens in the narrow subacromial space beneath the acromion, the bony peak of the shoulder blade. Structures like the rotator cuff tendons (especially the supraspinatus tendon) and the bursa can become inflamed and painful when repeatedly squeezed during arm movement. Diagnosis relies on specific physical maneuvers performed by a clinician and, often, medical imaging to visualize the underlying structures.
Professional Clinical Tests for Impingement
Health professionals employ specific provocation tests to reproduce the patient’s pain and identify shoulder impingement. These clinical maneuvers temporarily narrow the subacromial space, compressing the tendons and bursa. A positive result, indicated by a sudden onset of pain, suggests impingement is occurring.
The Neer’s Impingement Sign is performed by passively raising the patient’s internally rotated arm overhead. This motion forces the humerus against the undersurface of the acromion, pinching the supraspinatus tendon and bursa. Reproduction of pain during this passive forward flexion suggests mechanical impingement.
The Hawkins-Kennedy Test also attempts to compress the subacromial structures. The clinician flexes the patient’s shoulder and elbow to 90 degrees, then forcefully rotates the arm inward. This drives the humerus forward against the coracoacromial ligament, and pain during this maneuver is a positive sign for subacromial impingement. While these tests are sensitive for screening, a positive result does not confirm the diagnosis alone, as pain can arise from issues like tendonitis or bursitis.
To rule out associated conditions, such as a rotator cuff tear, professionals use muscle strength tests. The Empty Can Test (Jobe’s test) assesses the integrity of the supraspinatus muscle and tendon. The patient holds their arm out to the side and forward with the thumb pointing down, resisting a downward force applied by the professional. Significant pain or weakness during this resisted movement suggests supraspinatus tendon damage.
Simple At-Home Indicators and Self-Checks
Individuals can observe specific symptom patterns and functional limitations that indicate shoulder impingement before consulting a professional. The most recognizable sign is the “painful arc” of movement, which occurs when lifting the arm out to the side between 60 and 120 degrees of elevation. Moving the arm below or above this range is typically less painful because the tendon is not actively compressed within the subacromial space.
Another common functional indicator is difficulty and pain when reaching behind the back, such as fastening a bra or tucking in a shirt. This motion requires internal rotation, which irritates the inflamed structures. Night pain, particularly when lying directly on the affected shoulder, is also a frequent complaint.
These observations are merely indicators and not a definitive medical diagnosis. Experiencing these symptoms suggests a need for professional evaluation, as only a trained health provider can accurately diagnose the condition and differentiate it from other causes of shoulder pain. Self-checks should be performed gently and only within a comfortable range of motion to avoid exacerbating any potential injury.
Confirming the Diagnosis with Medical Imaging
While physical examination tests identify the condition, medical imaging is often necessary to confirm the structural cause and assess damage severity. X-rays are commonly used first to visualize the bone structure, not the soft tissues. They identify bone spurs (osteophytes) on the acromion that physically narrow the space, and help rule out other bony conditions like fractures or severe arthritis.
For a detailed view of the soft tissues, Magnetic Resonance Imaging (MRI) or an ultrasound is typically performed. MRI uses magnetic fields to create high-resolution images of the tendons and bursa, making it the standard for assessing rotator cuff tears or significant bursal inflammation. Ultrasound is less expensive and allows for dynamic, real-time visualization of the joint, effectively detecting inflammation and tendon damage.
Imaging does not diagnose the pain itself, which is a clinical finding based on the patient’s symptoms and physical exam. Instead, these technologies identify the underlying anatomical issues—such as a thickened tendon or a bone spur—that contribute to the compression and irritation of soft tissues. This information is crucial for guiding a long-term treatment plan.