The pectoralis major muscle is a large muscle in the upper chest, fanning across the chest from the shoulder to the breastbone. The two pectoralis major muscles, commonly referred to as the ‘pecs,’ ...

Your pectoralis major is a large and powerful chest muscle that’s shaped like a fan. It starts from two sections: your breastbone (sternum) and your collarbone (clavicle). The two sections come ...

The pectoralis major muscle originates from multiple locations, including the costal cartilage of ribs two through six, the sternum, the medial half of the clavicle and the external oblique fascia.