The subscapularis is at risk after anatomic shoulder arthroplasty.

Surgical repair cannot replicate the robustness of normal two-layer subscapularis inserting. The deep layer consists of parallel longitudinal fibers that insert onto the lesser tubercle flush with cartilage. The superficial layer is thicker and composed of interdigitated collagen bundles inserting onto the lesser and the greater tuberosity after splitting into two bands, one lining the floor of the bicipital groove, and the other extending over the long head of the biceps tendon across the groove; see Tendons, ligaments, and capsule of the rotator cuff. Gross and microscopic anatomy