The pectoralis major muscle is a large muscle in the upper chest that fans across the chest from the shoulder to the breastbone. There are two pectoralis major muscles, commonly known as “pecs,” that make up most of the chest. In addition to the pectoralis major, there are also two smaller triangular shaped muscles called the pectoralis minor. The pectoralis minor lies below the pectoralis major and aids in shoulder movement.
The pectoralis major muscles are used to control the movements of the arm and play a major part in deep inhalation. There are six, separate muscle fibers that have been identified within the pectoralis major muscles, which allow portions of the muscle to be moved independently by the nervous system. The pectoral muscles are more evident in males than females because the breasts tend to hide them.
Common injuries to this area occur during workouts, specifically during bodybuilding, and lifting heavy objects. Treatments include physical therapy, massage, and acupuncture.