The pectoral muscles are located on the chest, and span from the breast bone to the shoulders. The pectoral muscles make up a large bulk of the chest on the human body.
There are two types of pectoral muscles, namely the pectoral major and the pectoral minor with the pectoral minor lying underneath the pectoral major in the chest region. These muscles are more evident on men as women's breasts typically cover up much of their pectoral muscles. These muscles function mainly to help control arm movement in conjunction with shoulder muscles. The pectoral muscles also aid in deep inhalation.