The pectoralis major is a thick, fan-shaped muscle, situated at the chest (anterior) of the body. It makes up the bulk of the chest muscles in the male and lies under the breast in the female. Underneath the pectoralis major is the pectoralis minor, a thin, triangular muscle.
mouseover for muscle illustration photo by Carlos Arias
It arises from the anterior surface of the sternal half of the clavicle; and as low down as the attachment of the cartilage of the sixth or seventh rib. From this extensive origin the fibers converge toward their insertion; in a flat tendon, about 5 cm in breadth, which is inserted into the lateral lip of the bicipital groove of the humerus. (adapted from wikipedia)Other similar posts