Subscapular fossa

The subscapular fossa is a broad, concave area on the costal (ventral) surface of the scapula, which rests against the thoracic rib cage. It forms a major feature of this surface, occupying most of its area. The medial two-thirds of the subscapular fossa are marked by oblique ridges running laterally and upward, which serve as the origin for the subscapularis muscle, a powerful multipennate rotator cuff muscle. The lateral third of the fossa is smooth and covered by the muscle fibers of the subscapularis.