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What is the Pectoralis Major?

Alex Paul
Alex Paul

The pectoralis major is a muscle located in the chest of the human body. Its main function is to flex and rotate the humerus — a long bone in the upper arm. This is a large muscle that’s more visually prominent in males as it’s hidden underneath female breasts. Weight lifting is the most commonly used method for training this muscle. The pectoralis muscles are frequently referred to as pecs in everyday language.

The pectoralis major originates towards the center of the chest and is used to flex the arm or rotate it from the shoulder joint. This means that it’s an important muscle for a wide range of different tasks such as lifting and twisting the arm. An example of a movement that utilizes this muscle is bringing the arm across the chest.

The main function of the pectoralis major is to flex and rotate the humerus.
The main function of the pectoralis major is to flex and rotate the humerus.

The pectoralis contains two distinct muscles — major and minor. Both work in tandem but have different functions. The pectoralis minor is a muscle located beneath the pectoralis major. As the name suggests, the pectoralis minor is much smaller muscle. Its primary function is to draw the body forward from the scapula.

Due to the nature of the shoulder joint, it’s important for the pectoralis muscles to provide flexibility and movement in a number of planes. For this reason the fibers of the muscle run from the center of the chest outwards to increase mobility. People who have an injury to the pectoralis muscles may find everyday activities difficult because of this need for mobility.

Physical therapy may be helpful in treating severe pectoral injuries.
Physical therapy may be helpful in treating severe pectoral injuries.

The pectoralis muscles are one of the most important chest muscles for weight lifters and body builders. Exercises such as push ups and bench presses can be used to increase the strength of the muscle although these exercises don’t focus solely on the pectoralis muscles. There are other exercises that target the pectoralis major muscle, although these commonly require specialty gym equipment to perform effectively.

An anatomical illustration showing many muscles in the upper body, including the pectoralis major.
An anatomical illustration showing many muscles in the upper body, including the pectoralis major.

As pectoralis muscles are frequently overused during weight lifting, chest pain originating from this muscle is not uncommon. This could be a sign of a muscle tear or overuse injury. A person with a chest strain should rest the muscle as much as possible and refrain from any activities that may aggravate the condition. For more severe pectoral injuries, physical therapy may be required. Since chest pain can also be a sign of more serious conditions a doctor should always be consulted following an injury.

Discussion Comments

EdRick

For chest exercises, a lot of people think of bench press and pushups. And those can be great, but they actually work your arm muscles a lot, too. (Pushups, if done right, work your core; holding your body in that plank position works those stabilizing muscles.)

I think it's important to also do pec flies. Personally, I like to hold a free weight in each hand and lie down on a weight bench. With free weights, you know you're working the whole muscle because you have to steady the weight.

But with chest flies and bench press especially, you have to be careful not to injure your lower back. I see people at the gym all the time trying to life some really heavy weight, and they do it by arching their lower back! *Not* good. Your lower back should be in its natural, relaxed position at all times. If you aren't too tall, you might even want to bend your knees and place your feet on the bench. That really stabilizes your back so that you almost *can't* arch it.

jennythelib

I've always been taught that you should make sure to utilize opposite muscle groups. So to help prevent pectoralis major injury, you need to also work the muscles of your back (even if they are not as showy).

Or you could just get chest implants. I've heard that for men, they now make implants to give you that ripped look! (Think Batman in his molded costume.) It's hard to think of anyone who would *not* look foolish with those - if you're fit enough that you seem likely to have bulging chest muscles, you probably already have them!

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    • The main function of the pectoralis major is to flex and rotate the humerus.
      By: Balint Radu
      The main function of the pectoralis major is to flex and rotate the humerus.
    • Physical therapy may be helpful in treating severe pectoral injuries.
      By: Monkey Business
      Physical therapy may be helpful in treating severe pectoral injuries.
    • An anatomical illustration showing many muscles in the upper body, including the pectoralis major.
      By: mikiradic
      An anatomical illustration showing many muscles in the upper body, including the pectoralis major.
    • Doing push ups with elevated legs can strengthen the pectoralis major.
      By: bertys30
      Doing push ups with elevated legs can strengthen the pectoralis major.
    • A pectoralis major injury can make arm movement painful.
      By: patpitchaya
      A pectoralis major injury can make arm movement painful.
    • People who use weights to enhance their pecs often do bench presses.
      By: starsstudio
      People who use weights to enhance their pecs often do bench presses.