Serratus Anterior Muscle Beneath the Skin, Posterior View

Description

Seen from the posterior trunk beneath the skin, the serratus anterior is presented as a deep, fingerlike muscle wrapping from the lateral thoracic wall onto the anterior surface of the scapula. Its digitations arise from the external surfaces of the upper ribs and course posteriorly and medially to insert along the medial border of the scapula, with the strongest attachment at the inferior angle. Superficial to this plane, the latissimus dorsi forms the posterolateral contour of the back, while the thoracic spinous processes mark the midline and the rib cage arcs laterally beneath the muscle slips. Posterior access is where the serratus anterior is easiest to misread, because the muscle sits deep to the scapula yet controls scapular protraction and upward rotation through its anterior scapular insertion. Weakness from long thoracic nerve injury produces medial scapular winging that becomes obvious during a wall push-up, and this view helps distinguish true winging from apparent prominence caused by trapezius or rhomboid imbalance. Surgeons also care about the rib-based digitations during thoracic wall approaches and when raising muscle flaps for chest wall reconstruction. Key landmarks. Use this artwork for teaching scapulothoracic mechanics in gross anatomy and kinesiology labs, for atlas figures that contrast superficial back muscles with deep stabilizers, and for clinical education materials on winged scapula and serratus anterior dysfunction in sports medicine and rehabilitation settings. Anatomical accuracy verified by SciePro's Medical Advisory Board.