Pectoralis Major:A thick, fan-shaped muscle covering much of the upper chest, responsible for movements such as flexion, adduction, and internal rotation of the humerus.
Scapula:Also known as the shoulder blade, it is a flat, triangular bone located on the posterior side of the rib cage that provides attachment points for multiple muscles including the pectoralis minor.
Serratus Anterior:A muscle that originates on the surface of the 1st to 8th ribs at the side of the chest and inserts along almost all of its length into anterior medial border of scapula, playing a key role in scapular protraction and upward rotation