Detailed anatomy, crucial in modern high-definition diagnostics imaging, is a base for understanding diagnostic images and the nature of the diagnosed disease. The aim of this paper is presentation of a new anatomical model of the rotator cuff, which includes definition of tendinous and capsule-ligamentous layers as equally important to rotator cuff function understanding. Schematic and diagnostic (ultrasonography, magnetic resonance imaging) anatomy of the rotator cuff based on the core tendon concept is presented. Appropriate tissue layers of the cuff are discussed in detail. In the diagnostics part some enthesal pathologies of the rotator cuff are presented. Material and methods: New anatomical data was analyzed in the context of rotator cuff layers – their presence, thickness and structure observed on magnetic resonance imaging and ultrasonographic images. Conclusions: Rotator cuff should be regarded as a multilayer structure consisting of fused fibers of tendons and capsuloligamentous complex. The thickness of these layers is comparable therefore it is important to realize that capsular pathologies may become a serious obstacle to normal shoulder joint function. Understanding of anatomical rotator cuff layers explains the formation of calcific cavities within the rotator cuff. In fact between layers of the cuff. Calcific cavities are a sequelae of chronic enthesopathy/enthesal tear with hydroxyapatite filling and probably delaminating the tendinous layer from the capsuloligamentous one.