Zitat:
The chest is comprised of three separate muscles: the pectoralis minor (which is of little concern to us for now), the clavicular head of the pectoralis major, and the sternal head of the pectoralis major.
Because of its position up near the clavicle (collarbone), the clavicular head of the pec major is often simply referred to as the "upper chest."
Although many anatomists refer to the sternal portion of the pectoralis major as the "lower chest," for advanced physique-enhancement purposes we need to further divide this into two regions — the middle chest and lower chest.