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Linking the axial trunk and upper extremity, the shoulder joint plays an imperative role in most daily activities, allowing us to position our hands in space. Further, the joint acts as a small fulcrum for a long lever arm, predisposing the rotator cuff to injury, especially from the rapid accelerations and decelerations inherent to most sports and even some activities of daily living.
Shoulder anatomy and biomechanics, particularly those of the rotator cuff (RC), endow the glenohumeral joint with dynamic and static stability throughout a substantial range of motion. The interconnected supraspinatus, infraspinatus, teres minor, and subscapularis musculotendinous complexes constitute the rotator cuff and act as the shoulder's primary functional unit. Because of the rotator cuff's crucial role, RC pathology may lead to considerable limitations in daily routine, work, and leisure/sporting activities.
Shoulder magnetic resonance imaging (MRI) improves the sensitivity and specificity of diagnosing RC disorders, reduces unnecessary arthroscopic procedures, and provides important clinical information to guide patient management. This review will cover recent literature regarding RC anatomy and the clinical presentation, evaluation, and management of RC disease. We will discuss new observations about the strengths, inherent blind spots, and diagnostic effectiveness of shoulder MRI, and then outline the classification of rotator cuff MRI findings and their impact on patient management. Finally, we will present an effective search pattern approach to evaluate the rotator cuff on shoulder MRI examinations.
Normal anatomy
Knowledge of the RC tendinous insertions onto the proximal humerus, an area known as the rotator cuff footprint, makes it easier to determine the extent and location of abnormality. Much has been written recently about the anatomy of distal RC tendons as they interdigitate to insert upon the 3 facets of the greater tuberosity (superior, middle, and inferior), although their location and insertion appear somewhat more arbitrary by MR imaging. Standard landmarks and techniques used in MRI to demarcate the tendons will be elaborated upon later.
The supraspinatus muscle arises from the posterior aspect of the scapula, just above the scapular spine, and courses horizontally and anteriorly at the level of the acromioclavicular joint, a good landmark for its musculotendinous junction. The subacromial-subdeltoid bursa, which usually contains minimal fluid, if any, drapes over the supraspinatus muscle and tendon and lies just beneath the...