Serratus Anterior and Shoulder Health

The serratus anterior is an incredibly important yet often-forgotten muscle. It plays a vital role in proper shoulder movement. A strong serratus can help maintain long-term shoulder health. On the other hand, weakness of the serratus anterior can create problems with the shoulder girdle.

The serratus creates an essential base to movement for the upper extremity. But let’s face it – an exercise targeting the serratus anterior will never be a feature of your exercise routine. Let’s explore when and why to incorporate serratus exercises into a comprehensive training program.

When and Why to Use Serratus Exercises

I find that serratus exercises are best used in two ways. The first is during a warm-up as an activation exercise. The second is as part of an upper body superset.

Warm-up Activation

It is important to get this muscle engaged through an exercise directly targeting the muscle’s action. Activating the serratus during your warm-up can help make it more effective when asking it to help assist with other upper body exercises.

The serratus protracts and rotates the scapula (shoulder blade) upward. If the scapula cannot properly protract or rotate upward, the arm cannot fully elevate. This is why it is essential to get this muscle firing on all cylinders prior to beginning your heavy upper body lifts.

Upper Body Superset

The other time I like to program serratus exercises is to superset them with an upper body push or pull movement. While the serratus mainly assists during a pushing movement, it also needs to be active during a pulling movement.

Because of its influence on the scapula, the serratus is an essential compliment during upper body pushing exercises. This holds true for both horizontal and vertical pushing. Without full scapular elevation, you cannot hope to have full shoulder elevation.

The serratus also provides a stabilizing force to the scapula prior to initiating upper body pull exercises. If the shoulder blade is not held against the ribcage it becomes difficult to pull the upper arm back via the scapula.

Now let’s get into more detail about the muscle itself.

Anatomy of the Serratus Anterior

The serratus anterior is uniquely positioned on the thorax. It originates on the medial portion (closer to the midline) of the scapula. From there, it inserts on the lateral (away from the midline) border of ribs 1-8.⁽¹⁾ (Note – this muscle can also attach as far down as the 9th rib, as shown in the picture below).

The serratus anterior is innervated by the long thoracic nerve. This nerve is supplied by cervical roots C5-C7. After exiting the spine, these nerve roots run through the posterior scalene, then along the ribcage. From there, they innervate the serratus. Due to this nerve’s superficial nature, it is not uncommon to see pathologies of the long thoracic nerve.⁽²⁾ Disruption of this nerve supply may cause altered motion and control of the scapula, including “winging”.

In general, the attachment on the ribs remains relatively fixed, while the origin of the muscle can move with the shoulder blade. When the upper arm is free to move, the serratus is responsible for protraction, upward rotation and medial stabilization of the scapula. When the shoulder blade is fixed, contraction of the lateral attachment of the muscle to the ribs allows the ribs to elevate. This can help the serratus act as an accessory muscle for breathing.

See the muscle chart below for a summary of the anatomy of the serratus anterior:

Origin	Anterior surface of medial border of scapula
Insertion	Lateral border of ribs 1-8
Innervation	Long thoracic nerve (C5-C7)
Muscle Action	Open chain: Scapular protraction, upward rotation and stabilization Closed chain: elevation of the ribs

A Compliment to the Rotator Cuff

You can almost think of the serratus as the rotator cuff’s cousin. Instead of stabilizing the humerus (upper arm) on the glenoid (scapula) it maintains a stable and flat scapula on the rib cage as the arm moves. It provides stability to the medial portion of the scapula, while the rotator cuff stabilizes the humerus on the other end of the shoulder blade.

A weak rotator cuff does not properly stabilize the humerus in the glenoid. Meanwhile, a weak serratus will not properly stabilize the medial border of the scapula on the rib cage. Having instability of either end of the shoulder blade is not ideal. A properly functioning shoulder will have adequate strength and activation of both the serratus anterior and the entire rotator cuff.

Serratus Pathologies

The serratus anterior is an important muscle because of its direct involvement with the scapula. Keeping the shoulder blade flush against the rib cage helps to ensure proper shoulder movement and function.

As I mentioned earlier, the long thoracic nerve runs superficially compared to other nerves. This is not inherently a bad thing. However, it means there is less tissue around it to protect the nerve. The nerve also pierces and runs through the posterior scalenes. This is another area where the nerve may become entrapped, or pressed upon by the muscle. The course of the long thoracic nerve may predispose it to injury more than other nerves.

If the long thoracic nerve is injured, serratus anterior function can be compromised. This will typically manifest as scapular “winging”.⁽³⁾ Winging is abnormal movement of the shoulder blade where the medial border comes up off the ribcage. It almost looks like someone has grown wings! This is not only unsightly, but it can also disturb shoulder function.

Sometimes it does not take something as significant as nerve damage to cause scapular winging. Serratus weakness can also lead to this winging. Here are a few exercises to activate and strengthen this muscle to prevent abnormal scapular motion.

Exercises to Target Serratus Anterior

Supine Serratus “Scrape the Ceiling”

This may be the most basic exercise to target the serratus anterior. Years ago, I was looking for a better way to perform “serratus punches” (more on this later). I happened to stumble upon this video from the Prehab Guys.

I loved how the lever arm was shortened by flexing the elbow. The banded resistance also makes the exercise slightly more difficult as you move further through the motion. This exercise is great for scapular protraction, but I wanted to incorporate both actions of the serratus. I took this exercise one step further and added an elevation component on top of protraction.

By flexing the elbow, you take away the tricep’s ability to extend the elbow. You also create a mechanically advantageous motion for the serratus to protract and rotate the scapula upward. Weakness during scapular upward rotation may lead to the upper trapezius compensation and shoulder shrugging. By making a clearer path for the serratus to do its thing, you are less likely to activate the upper trapezius at the end of this motion.

Put all of this together and you have a killer exercise to target the serratus. Pure scapular protraction and upward rotation.

Quadruped Serratus Rock Back

This is also a very basic exercise that I like because of its closed-chain nature. I first saw this exercise used by Mike Reinold, while volunteering at Champion PT + Performance during my PT school days. He was using it for a baseball pitcher following thoracic outlet surgery. Thoracic outlet syndrome can be caused by a few different things. One of these is long thoracic nerve entrapment in the posterior scalenes, as referenced earlier.

The goal is simply to get the serratus to perform its job in a low-intensity environment. Think about pushing the ground away from your body. This will create protraction of the shoulder blade. From there, push your palms into the ground to rock your body back towards your heels. Now you have added upward rotation of the scapula. Make sure to limit any activation of the upper trapezius.

This exercise can be progressed in a couple ways. First, you can hold a band and wrap it around your back. This will add resistance as you push away and rock back. You can also perform this from a full push up position. This will increase the difficulty significantly, as it forces you to engage the core. With this said, these progressions will make it slightly harder to isolate the serratus. Make sure you are comfortable and confident with your serratus activation before trying to progress!

Serratus Foam Roll Elevation with Miniband

This is another great exercise that targets both the serratus and the rotator cuff external rotators. All you need is a foam roll and a miniband.

The goal is to push your forearms against the foam roll as you use the serratus to elevate the shoulder. Like the “scrape the ceiling” exercise, keeping the elbows bent creates a shorter lever arm. Again, this makes it easier to target the serratus.

I like to think of your elbows as the end of your “arm” in this exercise. Drive the elbows towards the wall to create scapular protraction, then drive into elevation. Think of performing an uppercut, or scooping motion with your elbows leading the way. Performing all these steps will again ensure that the upper trap does not compensate to create shoulder shrugging.

But why the miniband, you ask? Looping the miniband around your wrists forces you to activate your external rotators (infraspinatus and teres minor). The goal is to keep your forearms parallel as you elevate. The tendency is to let the elbows flare, which creates shoulder internal rotation. This limits engagement of the external rotators and may even cause the pectorals to kick in. Remember, the name of the game is to isolate the serratus so it can perform its main actions: scapular protraction and upward rotation.

By no means are these the only exercises that target the serratus anterior. There are so many other great exercises out there that also do an excellent job. I chose to focus on these three because they are relatively simple to perform. They also specifically target the serratus without significant contributions from a lot of other muscles.

With this said, there is a constant staple in serratus strengthening exercise: serratus punches. While it is very popular, I am not in love with this particular exercise…

A Classic Exercise I Don’t Prefer

Serratus Punches

The “serratus punch” is probably one of the most popular exercises to target the serratus anterior. This exercise is performed while lying down and is essentially just performing straight arm protraction. You can also hold dumbbells to add external load. There are a few reasons why I don’t prefer this exercise.

To start, this exercise is definitely not functional. When in life will you need to push dumbbells straight away from you while lying down? Now, the three exercises I explained are not necessarily functional either. You don’t really need to perform arm elevation against a foam roll with a miniband to be successful in life. However, they do place the serratus in an advantageous position to perform the muscle’s function.

Next, it is difficult to isolate the serratus anterior during this exercise. Keeping the arms extended creates a longer lever arm. With the arms extended, there is a tendency to utilize the triceps to complete this movement. This is another reason I prefer the “scrape the ceiling” and “foam roll elevation” exercises. By flexing the elbows, you create a shorter lever arm and take the triceps out of play. Doing this makes one less muscle available to compensate during this exercise and helps showcase the serratus.

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Try to incorporate some of these exercises into your training routine. Really focus on “feeling” these work the muscle. Activation and stabilization are key here, rather than chasing resistance or load. Focusing on the stability of the scapula will lead to improvements during your other upper body lifts. Give these a shot and see how it goes!

References:

1. Lung K, St Lucia K, Lui F. Anatomy, thorax, serratus anterior muscles. 2020 November, 14. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan.
2. Lung K, Lui F. Anatomy, thorax, long thoracic nerve. 2020 July, 31. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan.
3. Wiater JM, Flatow EL. Long thoracic nerve injury. Clin Orthop Relat Res. 1999 Nov;(368):17-27.