Serratus Anterior, Gross Anatomy

Description

Prominent along the anterolateral thoracic wall, the serratus anterior fans from the outer surfaces of the upper ribs toward the medial border of the scapula, where its slips converge deep to the scapular body. Anteriorly, translucent integument reveals the pectoralis major crossing from sternum and costal cartilages toward the proximal humerus, with the deltoid capping the lateral shoulder. Posteriorly and superiorly, the clavicle and scapular spine frame the shoulder girdle, while the humeral head sits lateral to the glenoid as the ribs and upper thoracic vertebrae define the cage beneath. Clinically, this muscle is the workhorse of scapular protraction and upward rotation, and its relationship to the long thoracic nerve is the teaching point: injury to the nerve on the lateral chest wall produces medial scapular winging and loss of overhead elevation. Its costal digitations also orient the viewer to common athletic patterns, the so called boxer’s muscle, where repetitive punching emphasizes serratus recruitment while scapular dyskinesis can persist when serratus activation lags behind upper trapezius dominance. A clean read of the rib attachments helps distinguish serratus anterior from adjacent pectoral fibers when planning incisions or interpreting surface anatomy. Use this plate for gross anatomy labs covering the pectoral girdle, kinesiology modules on scapulothoracic motion, and surgical education discussing lateral thoracic approaches where the long thoracic nerve is at risk. It also fits well in sports medicine or physical therapy materials illustrating scapular winging, serratus anterior strengthening, and differential diagnosis from spinal accessory nerve palsy. Anatomical accuracy verified by SciePro's Medical Advisory Board.