Capsular attachment of the subregions of rotator cuff muscles.

The posterior-deep subregion of the supraspinatus and middle partition of the infraspinatus evenly occupied the capsular attachment area. The transverse fibres were located just lateral to the medial edge of the firm attachment area, and the thick capsule had a substantial footprint. Both tendon fibres and the capsule inserted into the superior and middle facets through the attachment fibrocartilage.