What is the anatomy of the breast muscle?

The breast muscle, also known as the pectoralis major, is a large, fan-shaped muscle located in the chest area. It is composed of two main parts: the clavicular head and the sternal head. The clavicular head originates from the collarbone (clavicle) and the sternal head originates from the sternum (breastbone). These two parts come together to form the bulk of the chest muscle, which is responsible for movements like pushing and hugging.