The Chest Muscles - Pectoralis Major and Minor

The Chest Muscles

The human chest cosists of two muscles: Pectoralis Major, which is the bigger muscle and leads from the middle of the chest to the upper arm bone, and Pectoralis Minor, which is the smaller chest muscle and connects 3rd, 4th and 5th rib with the shoulder blade. The pectoralis major covers the pectoralis minor and is the big muscle bodybuilders want to focus on. It's quite common to say "Pecs" instead of pectoralis or chest muscles. Find exercises and information about other muscle groups at weight training main.


  • Pectoralis Major.
    The pectoralis major is the bigger muscle and goes from the middle of the chest to the upper arm bone. Its function is to move the upper arm forward. The shoulder muscles lift the arms, the chest muscles move them forward. The Pectoralis major consists of 3 parts. (see illustration above)
    • a) Pars Clavicularis / Upper Pectoralis Major
      You can work on your upper chest by doing bench press or flies on an incline bench. The higher you adjust your back lean, the more you will work your shoulders instead of your chest muscles. When you sit vertically and press your barbell straight up, we are not talking about a barbell bench press variation anymore. That would be military press.
    • b) Pars Sternocostalis / Middle of the Pectoralis Major
      Every chest exercise where you press the weight 90° from your trunk.
    • c) Pars Abdominalis / Lower Pectoralis Major
      For example decline barbell bench press or chest dips on parallel bars.
  • Pectoralis Minor.
    The pectoralis minor is the smaller chest muscle underneath the pectoralis major. Its function is to shrug the shoulder forward. When you bench press, you hardly work your pectoralis minor. Swimmers, on the other hand, usually have very well developed pectoralis minor muscles, which is the reason why their chest is usually thicker around the shoulder area. The pectoralis minor does not go all the way to the middle of the chest like the pectoralis major.


  • When you bench press, you should keep your shoulder still and low. The reason for this is not that you don't want your pectoralis minor to develop! The reason is that you lie down with your back on a bench and the shoulder blades would move when you use the pectoralis minor. When you do push-ups on the other hand, you can shrug your shoulders up and down without problem.
  • Swimming is a good exercise for the pectoralis minor.