American Board of Internal Medicine (ABIM) Certification Practice Exam

What is indicated by a positive painful arc test?

1. Subscapularis tear

2. Supraspinatus tendon tear

3. Subacromial impingement

4. Adhesive capsulitis

The correct answer is: Subacromial impingement

A positive painful arc test is indicative of subacromial impingement. This test evaluates the range of motion of the shoulder and typically involves the patient actively raising their arm in the plane of the scapula. During this movement, if the patient experiences pain between approximately 60 and 120 degrees of elevation, it suggests that the rotator cuff tendons, particularly the supraspinatus tendon, may be impinging against the acromion or the coracoacromial ligament. Subacromial impingement syndrome occurs when the subacromial space is narrowed, leading to irritation of the structures within this area, including the rotator cuff tendons and subacromial bursa. The positioning of pain in the painful arc is key to understanding this condition; pain that occurs at the beginning and end of the motion does not typically indicate subacromial impingement. This distinct pattern helps clinicians differentiate between various shoulder pathologies. Understanding this test is crucial for recognizing the highlights of shoulder mechanics and pathology, making it an essential component of shoulder assessment.