13/07/2026
Understanding the Shoulder Painful Arc: What Your Shoulder Is Trying to Tell You
Have you ever experienced shoulder pain only during a specific part of lifting your arm? This pattern is known as the Painful Arc, a valuable clinical sign that helps identify the source of shoulder pathology.
0°–45/60°: Usually Painless
The initial phase of shoulder abduction is generally comfortable because the humeral head has not yet entered the narrow subacromial space. During this stage, the supraspinatus initiates movement while the deltoid gradually increases its contribution.
60°–120°: Glenohumeral Painful Arc
Pain within this range often indicates pathology involving the glenohumeral joint or subacromial space. Common causes include rotator cuff tendinopathy, supraspinatus tears, subacromial bursitis, or shoulder impingement syndrome. As the arm elevates, the supraspinatus tendon and subacromial bursa pass beneath the acromion, where inflammation or structural narrowing can produce pain.
120°–170°: Usually Painless Again
Beyond 120°, the greater tuberosity clears the acromion, reducing compression of the subacromial tissues. Shoulder elevation is increasingly driven by coordinated scapulothoracic upward rotation, allowing smoother movement..
170°–180°: Acromioclavicular (AC) Joint Painful Arc
Pain near the end of shoulder elevation is more suggestive of acromioclavicular joint pathology, including AC joint arthritis, osteolysis, ligament injury, or post-traumatic degeneration. At maximal elevation, compressive forces across the AC joint are the greatest, reproducing symptoms.
Recognizing the location of pain during shoulder abduction helps clinicians differentiate between rotator cuff disorders, impingement syndrome, and AC joint pathology. Combined with a thorough physical examination and imaging when necessary, the painful arc remains a simple yet powerful tool in shoulder assessment.
