A With the origin fixed:Abduct the scapula (scapulothoracic joint)Upwardly rotate the scapula (S/T joint)Depress the scapula (S/T joint)Hold the medial border of the scapula against the rib cageWith the scapula fixed:May act to elevate the thorax during forced inhalationO External surfaces of upper eight or nine ribsI Anterior surface of medial border of the scapula The Serratus anterior is a fan shaped muscle Serratus Anterior