Serratus Anterior Muscle, Lateral View

Description

Seen from a lateral perspective, the serratus anterior appears as a series of serrated digitations arising from the external surfaces of the upper ribs (classically ribs 1 to 8 or 9) along the anterolateral thoracic wall. The slips course posteriorly and slightly superiorly to converge on the costal (anterior) surface of the scapula, concentrating along the medial border and toward the inferior angle. The scapula lies posterior to the rib cage, so the muscle reads as a bridge from the lateral chest to the deep surface of the shoulder girdle. For teaching scapulothoracic mechanics, this angle is hard to beat because it makes the muscle’s rib origins and its relationship to the scapular medial border immediately legible, which is exactly what you need when explaining protraction and upward rotation during arm elevation. Clinically, serratus anterior weakness from long thoracic nerve injury produces medial scapular winging, often seen after axillary surgery, chest tube placement, or traction in contact sports. That landmark matters. You can also tie the digitations to chest wall pain patterns and to why the muscle is encountered when raising serratus anterior flaps for reconstructive surgery. Use it in gross anatomy lab manuals, kinesiology modules on shoulder rhythm, and surgical education pieces covering axillary lymph node dissection or thoracostomy technique where long thoracic nerve protection is emphasized. It also fits radiology and sports medicine teaching on scapular dyskinesis and winging on physical exam. Anatomical accuracy verified by SciePro's Medical Advisory Board.