The pectoralis minor is a thin, triangular muscle located beneath the larger pectoralis major in the chest. It originates from the third, fourth, and fifth ribs and attaches to the coracoid process of the scapula. This muscle plays a crucial role in stabilizing the shoulder blade and assisting in movements such as lifting the arm and pushing. In addition to its role in shoulder movement, the pectoralis minor also helps with deep breathing by elevating the ribs when the shoulders are fixed. It is innervated by the medial and lateral pectoral nerves, which are branches of the brachial plexus.