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Serratus Anterior Training Progressions

The serratus anterior is like that kid you knew in high school everyone knew: a bit mysterious and misunderstood, who was not necessarily in trouble, but was always around trouble when it happened.

 

Kato Kaelin may be the human equivalent of the serratus anterior

 

It isn't really a muscle that takes a regular beating like the long head of the biceps in a thrower, nor is it "married" to a joint complex like, say the supraspinatus.  However, more often I see it being a problem in people with traumatic neck pain (such as whiplash injuries) in addition to older patients with non-athletic shoulder pathology.

Obviously, overhead athletes (particularly tennis, baseball and swimming) with shoulder pain may have serratus activation/weakness issues, but the big trend I'm noticing is serratus under activation/ weakness in cases of neck pathology, particularly those of a traumatic nature.  This applies again to acceleration injuries such as whiplash, but also to athletes involved in collision sports (football, wrestling, MMA).  This recent study highlights the link between serratus dysfunction, poor muscular activation and cervical/thoracic dysfunction.

Anatomy of the Serratus Anterior

The serratus is definitely an oddly shaped muscle.  The best way to think of the serratus is to think of a hand. The origin(s) of the serratus are shaped like fingers and grasp the superior borders/ outer surfaces of the upper eight or nine ribs (o.k., we don't have nine fingers, but I get a pass on this one).  Your palm is the "body" of the muscle, while the wrist crease is the insertion of the serratus on the medial scapular border.

 

The "classic" anatomy book rendition of the serratus anterior

 

 

Typically what we think of when we see a serratus in a lean individual

 

 

The serratus wholly dissected looks  kind of like this, that is if we had eight or nine fingers

 

Function of the Serratus Anterior

According to Kendal (Muscles Testing and Function, fourth edition), the functions of the serratus anterior are numerous, including letting the glenoid cavity of the scapula (the "socket" of the shoulder joint) rotate upward, as well as holding the medial border of the scapula against the rib cage. Also, the lower fibers may depress the scapula a bit.  I think both clinically and from a performance standpoint that the last two functions are very important. 

First, keeping the scapula held firmly to the rib cage by way of proper serratus function allows properly functioning "anchor points" for the rest of the scapular musculature,  the rotator cuff, as well as the middle and lower trapezius, as well as the levator scapula and upper trapezius.  Secondly, as an end range scapular depressor following the mild  concave contour of the rib cage, I believe we may ultimately help foster qualitatively improved glenohumeral elevation by lessening anterior scapular tilt

The Serratus/Rhomboid Fascial Connection

In "Anatomy Trains", Thomas Myers points out the fascial/septal connection between the serratus anterior and the rhomboids.  We know from Kendall that the rhomboids are antagonistic to the serratus (or as she puts it "direct opponents"). Myers coins the term "rhombo-serratus" muscle,pointing out the two muscles form a myofascial scapular sling, setting up scapular "ballast".  The two muscles appear as "kissing cousins" in these illustrations/ dissections.  So, as the serratus goes, the rhomboids will go (and vice versa), both from a length (short/stiff) issue as well as an activation/contractility issue.

 

Thomas Myers- The "Christopher Columbus" of the Anatomy World

 

These passive, active, and cozy connections provided me with an "a ha" moment when working two patients recently, both who had traumatic neck injuries related to whiplash, and my approach to their treatment.  

Both had multiple issues, including loss of neck and shoulder mobility due to soft tissue injury, and the loss of mobility was due to multiple factors, including segmental tightness at the cervical facet level and posterior shoulder capsule/element tightness.  Obviously these were treated in concert with soft tissue work to the rhomboids (at the point of insertion on the medial scapular border), activation work for the middle and lower trapezius, and postural restoration activities.

 

Weaving the Serratus/ Rhomboid Tapestry

When it came time to train the serratus, I utilized a three phase approach based on 1) supporting still sensitive, sub acute healing  cervical/ thoracic structures 2) gradually decreasing external support as our injured tissues allow 3) giving the rhomboids "equal time" to allow seamless integrated contractility/ activation in conjunction with the serratus.

Phase 1

I use a massage chair for trunk support to dial in what I want the patient to perceive as appropriate serratus function (scapular protraction with shoulder elevation).  The key is to maintian scapular protraction while elevating; retraction during elevation indicates poor serratus function and/ or too heavy a load.

 

 

Phase 2

As the patient gains an understanding of how to activate the serratus and control the scapula, we then move to a seated position to allow/ integrate trunk stability while the serratus does it's job:

 

 

Phase 3

After we have mastered the first two progressions, we then move to a standing position, which integrates further the trunk with the hip.  Again, Thomas Myers notes a fascial/septal connection between the serratus as well as the obliques and tensor fascia lata; standing allows potential stabilization/ integration between these elements:

 

Integrating Rhomboid Activation

The X factor that was missing in the equation for me in the past was addressing rhomboid function.  I had been so focused on not aggravating the upper trapezius/ levator scapula that I avoided rhomboid activation as I felt it encouraged too much "turn on" of the aforementioned groups.  However, with recent patients, careful integration of specific rhomboid work "greases the groove" for the rhombo-serratus anatomy train, and allows appropriate tri-phasic (concentric/isometric/eccentric) interplay in a scapula with great myofascial ballast (courtesy of early and appropriate soft tissue work, joint mobilization and postural restoration).  

Here, we perform a static rhomboid activation, careful to minimize upper trapezius and levator activity:

 

 

Beyond Basics:

After we've got our "new normal" scapular function, we can progress through our preferred  "pushing"upper body exercises.  I am biased toward push up progressions at first, as scapular mobility is encouraged vs. locking the scapula down with a bench press.

My personal favorite test of good serratus function is a handstand hold, as I feel  a real satisfying scapular position on the ribcage with this exercise: 

 

 

 

 

At The End of the Day…

1) The serratus anterior is a tough muscle to wrap your head around from a three dimensional standpoint; however it's function really is a keystone for proper scapular function (and the scapula is a keystone for trunk/ extremity integration, if you really think about it). 

2) Serratus function is an interplay between both the serratus and the rhomboids, both from a passive (shortness/ stiffness) perspective, as well as an active one; both need to be addressed.

3) Strengthening the serratus is more about proper, integrated activation in conjunction with the rhomboids after appropriate positioning/ballast of the scapula has been established through appropriate manual therapy/postural intervention.

4) Advanced upper body push activities should allow free scapular movement, such as push up, dip and pressing pattern progressions as tolerated (remember to pick your candidates carefully for pressing and dipping)