Dudex

I thought (and am probably wrong) that the chest consisted of pectoralis major and minor, the major being the larger and connected to the scapula (collar bone) and the sternum (chest) and running across to the humerus (arm). The minor runs from ribs 3, 4 and 5 to the scapula. If developed you can see the minor, looks like a small ridge arcing off of the major just below the nipple.

Personally declines seemed to work the minor more, and I could see the muscle, looked a little bit weird (lol).