Snapshot A 70-year-old man presents to his physician for left shoulder pain for the past several months. He reports that he cannot reach above his head without any pain. As a retired carpenter, he reports that this has significantly impacted his quality of life. Additionally, he is unable to lie on his left side at night due to shoulder pain. On physical exam, there is focal tenderness over the left anterolateral shoulder. Radiography reveals reduced space between the acromion and humeral head. Introduction Clinical definition injury to 1 or more of the rotator cuff muscles injury is typically due to tear or tendinopathy rotator cuff muscles, which are all innervated by C5 and C6, are the SITS Supraspinatus innervation suprascapular nerve function initial abduction of the arm (0-15°) Infraspinatus innervation suprascapular nerve function lateral rotation of the arm Teres minor innervation axillary nerve function adduction and lateral rotation of the arm Subscapularis innervation upper and lower subscapular nerves function adduction and medial rotation of the arm Epidemiology Incidence the supraspinatus muscle is most commonly injured Demographics adults Risk factors older age smoking repetitive overhead reaching Etiology Pathogenesis acute avulsion injuries typically following trauma chronic degenerative tears repetitive overhead motions tendon weakening due to degenerative changes and chronic impingement Associated conditions biceps tendinopathy osteoarthritis Presentation Symptoms shoulder pain exacerbated by sleeping on the affected shoulder reaching overhead limited function of the shoulder Physical exam severe focal tenderness at the insertion of supraspinatus (anterolateral shoulder) decreased active elevation with normal passive range of motion Hawkins impingement test passive internal rotation of the shoulder with the patient seated and elbow flexed 90° test is positive if there is pain Neer impingement test passive elevation of the arm while internally rotated with the patient standing test is positive if there is pain painful arc sign pain with active abduction between 60° and 120° empty can test patient with arm elevated to 90° with elbow extended and thumbs down clinician applies a downward force on the arm while patient resists test is positive if there is pain 90% specificity for supraspinatous pathology Imaging Radiography indication for all patients as initial imaging findings loss of subacromial space, due to upward migration of humeral head Magnetic resonance imaging (MRI) indications if radiography is normal but there is suspicions for rotator cuff injury not indicated for all patients most accurate test Studies Making the diagnosis most cases are clinically diagnosed Differential Adhesive capsulitis distinguishing factor active and passive range of motion are limited Treatment Conservative physical therapy indication for all patients Medical nonsteroidal anti-inflammatory drugs (NSAIDs) indications for all patients pain management steroid injections indication for patients who fail NSAIDs as pain management Operative surgical repair indications for patients with complete tears for patients who fail all other more conservative management of 3-6 months Complications Functional limitations Adhesive capsulitis Prognosis Re-tear may occur