The anatomy of the subscapularis tendon insertion as applied to rotator cuff repair.

The tendons constituting the rotator cuff (RC) are often torn, and several techniques for their repair have been established. The existence of an extension of the supraspinatus tendon into that of the subscapularis has often been overlooked. The purpose of this study was to study this extension in human dissections. The possible posterolateral extension of the subscapularis tendon and the interdigitating of this extension with the supraspinatus tendon were addressed. A horizontal band of tissue 1 cm below the superior ridge of the greater tuberosity of the humerus was harvested from 43 cadavers and thus included tissue constituting the greater tuberosity, bicipital groove, and lesser tuberosity. The sample extended 2 cm medially along the lesser tuberosity and 1 cm laterally along the greater tuberosity. Macroscopic findings suggest a continuous band of tissue extending across the bicipital groove. High collagen content was microscopically confirmed at different sections, and the collagen was densely distributed along the horizontal axis of the tissue samples.