Muscle Breakdown: Pectoralis Minor
Table of Contents
What Is the Pectoralis Minor
The pectoralis minor is a triangle-shaped muscle found underneath the pectoralis major. Although it’s such a small muscle it can be the source of various injuries and dysfunction within the shoulder complex. Understanding the pectoralis minor will help you prevent and fix injuries stemming from this overactive muscle. So in this muscle breakdown, I'll explain everything you need to know about the pectoralis minor.
Pectoralis Minor Muscle
Pectoralis Minor Origin and Insertion
Pectoralis Minor Origin
The pectoralis minor origins are found on the rib bones on the chest. The ribs serve as an anchoring point for the functions that act on the scapula. The origins of the Pectoralis minor can vary depending on your genetics.
Ribs 3-5
Pectoralis Minor Insertion
Because the pectoralis minor attaches to our scapula. Movements in the arm won’t directly activate your pectoralis minor. If you want to stretch or train the pectoralis minor you have to focus on the scapula, not the arms.
Coracoid Process
Pectoralis Minor Function
Scapula
Anterior and Inferior Tilting of the Scapula
Protraction
Downward Rotation
Stabilization
Ribs
Inhalation
Pectoralis Minor Pain & Injury
This muscle breakdown will place an emphasis on injuries associated with the pectoralis minor since it is the cause of many issues within the shoulder region.
Rounded Shoulders
One of the most common dysfunctions we see with regards to the pectoralis minor is the rounded shoulder. Many spend the majority of their lives with rounded shoulders, particularly past the age of 30. Rounded shoulders are typically accompanied by kyphosis the rounding of the thoracic region of the spine. The combination of the two is commonly referred to as upper cross syndrome. A condition that results in pain, and dysfunction in the shoulders, neck and upper spine.
Why does the pectoralis minor cause rounded shoulders? The pectoralis minor becomes overactive and shortened, forcefully pulling from insertion point to the origin. Remember, the pectoralis minors draw the scapula forward and down. Essentially placing the shoulders into that rounded position. If the thoracic spine has kyphosis, the rounding of the upper back, it will accentuate the rounding of the shoulders even further.
Who is at risk of getting rounded shoulders? Unfortunately, the rounding of the shoulders is extremely common due to our daily activities. Operating computers, driving, slouching, and incorrect exercise form creates and worsens our posture. Essentially any situation that allows a slouched posture for extended periods of time will round our shoulders.
How to Fix Rounded Shoulders
Getting rid of rounded shoulders is a multi-stage plan that requires you to tackle it from different angles to fix and prevent.
Practice Good Posture
Recognize your shoulders are rounded throughout most of your day and try to avoid it as best as possible. This doesn’t mean stop doing that activity, instead, modify it. Occasionally remember to pop your chest out, retract and depress your shoulder blades. A cue I like to use is pinching your shoulder blades together and push them down into your back pocket.
This is the opposite function of the pectoralis minor taking us out of that rounded position. At first, it will feel awkward but as you continue practicing good posture this will slowly become more natural. Using ergonomic aids can help like a standing desk and an exercise ball for a chair.
Stretch the Pectoralis Minor
The pectoralis minor gets very tight since it’s always in a shortened position. Make sure to stretch the pectoralis minor frequently to help lengthen this muscle. Learn about pectoralis minor stretches in the stretching section of this article.
Use Myofascial Release
When we're stretching, we are pulling the two ends of the muscle apart to lengthen the muscle. But the tissue between the two ends still needs to release. Research indicates we create a lot of neural tones when a muscle is overactive.
This is a resting contracting created by neurological signals. Using any form of a myofascial release will alleviate that built-up tension. Ideally, you want to use a tool small enough to reach this small muscle. Or you can utilize massage therapy from a certified sports massage therapist. Either way, Myofascial release is an effective tool that can make the process a lot easier.
Strengthen the Back Muscles
Just because our pectoralis minor is lengthened, it doesn’t mean it will maintain the new length you've created. Many of the back muscles like the trapezius, rhomboids, Reverse deltoids, and latissimus dorsi are powerful muscles that prevent rounding of the shoulders. When these muscles are strengthened, they will perform the opposite functions of the pectoralis minor.
Pulling the scapula back into a more natural position. This will make corrections and maintenance of shoulder rounding much easier and is one of the most crucial steps. In addition, these muscles are also strong spinal extensors which will help elevate thoracic kyphosis. Another key factor in fixing rounded shoulders.
Learn more about strengthening the back muscles through their own dedicated articles.
Thoracic Outlet Syndrome
Avoid over the Engagement of the Pectoralis Minor During Exercises
You might be wondering how the pectoralis minor affects your workout. During exercise, you should limit the activation of the pectoralis minor as much as possible. Overactivation is the cause of shoulder rounding and is a risk factor for thoracic outlet syndrome. The best advice I can give is to not let your shoulders round during any exercises. Having your shoulder rounded while being placed under external loads will further exacerbate the problem. Be cognizant and maintain a good scapular position. No exercise requires rounding of the shoulders so avoid it as much as possible.
Exercises That Over-activate the Pectoralis Minor
There are a few exercises where over activation of the pectoralis minor will occur due to shoulder rounding. Rounding is not part of the form or technique. It’s just more likely since a rounded shoulder position feels more natural. This doesn’t mean you should stop doing these exercises, instead, you should perform them with proper form and scapular position to avoid the over engagement of the pectoralis minor.
Above the Knee Rack Pull
Chest flies
Pectoralis Minor Exercises
There are few occasions where you would want to strengthen the pectoralis minor. But to eliminate the risk of developing rounded shoulders, we want to focus on a different function of the pectoralis minor which is shoulder protraction. Training shoulder protraction will simultaneously strengthen the pectoralis minor and the serratus anterior.
The serratus anterior plays a vital role in scapular upward rotation and is necessary for fluid overhead motion. A strong serratus anterior will also pull the scapula flat against the posterior rib cage helping eliminate rounded shoulders. Read more about the serratus anterior through our dedicated article.
Push Up Plus
Push-ups plus are regular push-ups but with added scapular protraction at the top of each repetition. This engages both pectoralis minor without the need for rounding the shoulders. All while strengthening the weak serratus anterior. Push up plus are also very time effective as it strengthens many muscle groups simultaneously. Primarily the pectoralis major, pectoralis minor, serratus anterior, anterior deltoids, and triceps brachii.
Bonus: Perform your push-ups plus with a close grip. The close grip allows for a greater range of scapular protraction increasing muscle activation of the shoulder protractors.
Dip Plus
The dip plus is a regular dip with an added scapular protraction at the top of the repetition. Dips are a more advanced progression to the push up which requires more strength in order to be done correctly. I highly recommend adding in the dip plus since it is a very time-efficient exercise. Like the push-up plus, it strengthens multiple muscle groups simultaneously.
Prone Core Exercises with Scapular Protraction
Any core exercises where the front of your body is facing the floor can be done in a scapula protracted position. This turns already effective core exercises into a pectoralis minor strengthening exercise. My personal favourites are planks, rollouts, body saws, and pikes.
Pectoralis Minor Workout
Structuring your pectoralis minor training is going to be different than most muscle groups since there's no need to train the pectoralis minor. This is due to the pectoralis minor already being very overactive. Your regular workout routine will be more than enough to maintain pectoralis minor strength.
I would place a strong emphasis on training the muscles around the pectoralis minor and the back muscles to prevent shoulder rounding. Adding some form of horizontal and vertical pull with rotator cuff strengthening exercises will help prevent and fix shoulder rounding. Included exercises like the cable face pulls, cable external rotations, and some form of scapular protraction.
Make sure your current training routine has a 1:1 ratio of pushing to pulling exercises. This will prevent muscular imbalances which will further exacerbate an overactive pectoralis minor. For example, for each set of bench presses do a set of barbell rows. This also applies to vertical pushing and pulling so for every set of the overhead press do a set of chin-ups. I would also spend extra time during your cool down to stretch or perform myofascial release on the pectoralis minor. The extra time and effort put into lengthening the pectoralis minor are well worth it since we spend most of our day in a shortened position.
Sample Exercise Routine to Fix Overactive Pectoralis Minor
Sample Workout
| Exercise | Sets | Repetitions | RPE/1RM | Rest |
|---|---|---|---|---|
| Barbell Row | 4 | 6-8 | 8 | 2-3 min |
| Push Up Plus | 3 | 6-8 | 8 | 2-3 min |
| Pull Ups | 4 | 6-8 | 8 | 2-3 min |
| Cable Face Pull | 3 | 20 | 9 | 2-3 min |
| Plank with Scapular Protraction | 3 | 30 Seconds | 9 | 2-3 min |
Pectoralis Minor Stretches
Remember our pectoralis minor doesn’t attach to our arms. It attaches to our scapula through the coronoid process. So our regular pectoralis major stretches won’t be as effective. You can still perform most of your pectoralis major stretches. But have the pushing force be applied to the anterior of the scapula as opposed to your arms. The pectoralis minor is also hard to reach since the pectoralis major covers the pectoralis minor. I recommend using a small tool to help release the pectoralis minor.
Door frame shoulder girdle stretch
Foam rolling, lacrosse ball, massage and myofascial release