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Chest 101: Anatomy and Training Smart

Always wanted that well-defined square chest? Learning about the anatomy of the chest will help you optimize your workouts!


A well-defined chest requires a good understanding of the anatomy of the chest to select the best workouts. Image credit: istolethetv, Flickr

The chest has always been an important training component for men and women alike. Growing the chest will help strengthen your upper body and enable you to do more challenging workouts to keep you fitter.


The understanding of the chest anatomy will help in making sure you are doing your workouts correctly, and ensure you optimize your workouts to achieve the best results. Unlike the abdominals, the chest is just made of two simple muscles—the pectoralis major and the pectoralis minor.



Pectoralis major

The pectoralis major is a fan-shaped muscle that connects your clavicle, ribs, sternum and upper portion of your humerus (upper arm bone). It can be categorised into three parts for bodybuilding purposes: the upper, middle and lower chest.

The clavicular refers to upper chest; Sternal, the middle chest and Costal, the lower chest. Image credit: Books of Discovery 2014

The upper chest is the clavicular head of the pectoralis major that connects to the clavicle (collarbone). The middle and lower chest make up the sternalcostal portion of the pectoralis major and for obvious reasons, is connected to the sternum.

To fully engage the pectoralis major, you just have to do a fly. The fly movement involves a horizontal adduction where your arm is brought across the front of your body and internal rotation of the humerus.


Let's take a look at how each part is involved. When you flex the shoulder joint, the upper chest is in motion, working with the anterior deltoid (upper back) to raise the arm to the front. Extending the shoulder joint will in turn engage the lower chest.


The middle chest fibers run horizontally and do not contribute significantly to the movements of shoulder flexion or extension, but instead is involved in bringing the humerus to the chest, horizontally.


Here's a summary:

How the pectoralis major works in the movement of horizontal adduction. Chart credit: Dr. Clay Hyght, TNation.

Pectoralis Minor

The little brother to the pectoralis major, it is a thin, triangular muscle below the pectoralis major that attaches from the scapula (shoulder blade), to the 3rd, 4th and 5th rib. It helps with pulling the shoulder forward and down.


The pectoralis minor plays a supporting role to the pectoralis major. Image credit: Books of Discovery 2014

As it hides behind the pectoralis major, and is involved supporting the pectoralis major and most shoulder movements, more focus is put on exercises that grow the pectoralis major.



Angles and emphasis

It is time for a chest assessment. Contract your chest and take a good look in the mirror. Is your chest more prominent in the upper, middle or lower section? Or does it look even? Is it all hard muscle or do some parts feel softer?


People often mistake fat in the lower chest region as good lower pectoralis development. So, the first step is really to get striations in your chest to have a precise assessment. However, it is also possible by poking around your chest to see how deep the softness goes.


Once you have identified your chest development, you might want to plan your workouts that emphasise (not isolate) the different parts of your chest that require more development.


All exercises work out the entire chest, but place emphasis on different parts of the chest.



Elevated cable flies are best to target the lower chest, often a common problem to obtaining an evenly-developed chest.

Avoiding injuries and training smart

Sometimes lifting weights and doing multiple repetitions of an exercise does not work. Your body is a dynamic and ever-changing unit that adapts easily to the stimulation and stress you put on. That is why you need to select the right exercises correctly.


Having a good mindset is also key to achieving your goals. Be smart and select your exercises instead of trying to do a random chest workout. This will help you achieve the balanced chest.

Most importantly, do not rush and try to lift heavier than you should. We commonly see shoulder injuries when gym goers try to speed up their chest development, going heavier than they should. Having an injury will greatly limit your development in the long term.


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