The rotator cuff consists of four muscles and their tendons: supraspinatus, infraspinatus, teres minor, and subscapularis. Ultrasound is a first-line imaging modality for evaluating rotator cuff pathology, including tendinosis, partial-thickness tears, and full-thickness tears. The supraspinatus is the most commonly injured tendon. A complete supraspinatus tear appears as a focal or complete absence of the tendon with joint fluid or fat filling the defect. Dynamic assessment with shoulder abduction and external rotation improves visualization and allows real-time evaluation of subacromial impingement.