The pectoralis minor muscle is the smaller of the two sets of muscles that connect the bones of the chest to the shoulder and upper arm. Sitting in the axilla and largely below the pectoralis major, the thin pectoralis minor muscle fastens to the shoulder blade (scapula) at the coracoid process and connects it to the center of each side of the chest near the cartilage of the middle ribs (anterior, sternal surfaces generally of the third through fifth ribs). Counterposing the trapezius muscle, the pectoralis minor works to move the shoulder both down and forward, as directed by the medial pectoral nerve. Triangular in shape, the pectoralis minor muscle rises and narrows to the upper and medial portions of the coracoid process.