Subscapularis Muscle, Medial View

Description

Arising from the subscapular fossa on the anterior (costal) surface of the scapula, the subscapularis forms a broad, thick muscular sheet that lies directly against the posterolateral thoracic wall. A medial viewpoint places its belly deep to the scapular body, with the serratus anterior and the ribs immediately medial, and the tendon converging laterally toward the lesser tubercle of the humerus. Superiorly, the muscle approaches the scapular spine and coracoid base; inferiorly it tapers toward the inferior angle, where the scapula glides over the rib cage. Medial access matters because subscapularis is the anterior component of the rotator cuff and a frequent source of anterior shoulder pain and weakness in internal rotation, yet it is often underappreciated compared with supraspinatus tears. This orientation clarifies why subscapularis lesions may coexist with instability of the long head of the biceps, since the tendon’s upper border contributes to the biceps pulley at the rotator interval and fails with partial-thickness articular-sided tears. It also helps explain the mechanics and surgical rationale of subscapularis release and repair in total shoulder arthroplasty and in open stabilization procedures. Orthopaedic anatomy courses can use this artwork to teach scapulothoracic relationships and the anterior rotator cuff footprint without relying on an anterior skin-on view. Sports medicine texts and surgical atlases will find it suitable for discussing belly-press and lift-off test anatomy, subcoracoid impingement, and repair planes during deltopectoral approaches. Anatomical accuracy verified by SciePro's Medical Advisory Board.