It’s true that Serratus Posterior Inferior is not the musclebrity that Serratus Anterior is.  If you read up on yoga anatomy, or take yoga from a teacher who does, you’re most likely enamored with your Serratus Anterior (a crucial scapular stabilizer in almost every inversion and arm balance).  That being said, I wouldn’t necessarily recommend writing Serratus Posterior Inferior off the A-list of muscles you should know about.  Especially if you’re interested in practicing a breath control technique called the Yogic Complete Breath.

The Serratus Posterior Inferior is highlighted in red here.

As practiced in the YTU method, a Yogic Complete inhalation takes place in two phases to maximize lung capacity.  Phase one of this yoga breathing technique secures the rib cage (Enter Serratus Posterior Inferior.  But more on that later!) so just the lower belly swells until the lungs are about 75% full. In phase two, the yogi permits the rib cage to lift upward filling the lungs the remaining 25% of the way. Try it!  Bring your spine into a neutral position.  Fully exhale.  On inhalation, only let your belly puff out.  ¾ of the way through let your ribs puff up as well.  Exhale passively.  Repeat several times and observe how this pranayama boosts lung capacity.

How does this work?  In phase one of the Yogic Complete inhalation, the diaphragm (a domed muscle that horizontally divides your trunk into its thoracic and abdominal cavities) flattens downward toward its inferior attachments on the lowest 6 ribs and lumbar vertebrae, packing your abdominal organs deeper down and clearing space for your lungs to swell. Your belly bulge is evidence of organ displacement as you take an abdominal inhalation. Phase two completes the process with a thoracic inhalation, during which the ribs puff upward and outward further augmenting space for the lungs to engorge.  [This rib expansion is also assisted by the diaphragm’s attachments to the ribs.] It’s phase one that we’re concerned about with regards to the importance of Serratus Posterior Inferior and its role in bracing the rib cage to leverage a deeper descent of the diaphragm.

Like all muscles, the attachment sites of Serratus Posterior Inferior determine its function. Its serrated strips connect from the spinous processes (the jagged topography of your spine felt through the skin of your back) of vertebrae T11-L2, and reach upward and outward to ribs #9-#12.  Seen from a posterior view of the skeleton, both the right and left Serratus Posterior Inferior muscles form a shallow V that overlay the lowest floating ribs.  SPI’s function is to anchor ribs #9-#12 downward toward its attachment on the spinous processes below so that the ribs don’t elevate during the first phase of the Yogic Complete Inhalation.  But why would we want to secure the ribcage during phase one?

Imagine you have wedged yourself between a heavy dresser and a wall with the hopes of shoving the dresser out into the middle of the room with your legs. With your back against the wall, you harness the complete force of your legs, including the rebounding force, which, because of the wall behind you gets redirected back into the dresser. To put it another way, imagine how much harder it would be to move the dresser if while pushing with your legs, both the dresser and the wall moved. The dresser would only move ½ the distance!  In this metaphor, the diaphragm is the pusher wedged between the rib cage and the abdominal organs.  Its job is to move the abdominal organs down and out of the way to make space for the lungs above to inflate.  Just like the role of the wall, in stage one of a Yogic Complete inhale, we want the ribcage to remain stable so that the diaphragm’s descent downward isn’t diminished by the ribcages ascent upward. Serratus Posterior Inferior (along with help from its synergist friends) cancels out the ribcages inclination to elevate.  This maximizes the influx of breath during stage-one of the Yogic Compete inhale, making stage two, or the thoracic inhalation, icing on the oxygenation cake.

For this reason, Serratus Posterior Inferior deserves some recognition and respect.  Please, next time you hear somebody fawning all over Serratus Anterior, take a moment to remember and appreciate Serratus Posterior Inferior too.  It IS inferior with regards to its position on the body map, but certainly NOT with regards to its role in enhancing the pranayama technique, Yogic Complete Breath, or in Serratus Posterior exercises.  Your diaphragm descends deeper and your body’s cells receive more oxygen because of it.

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Laurel Beversdorf

Laurel Beversdorf is an international yoga and interdisciplinary movement educator specializing in anatomy, biomechanics and yoga teaching pedagogy. She is an integrated Yoga Tune Up® teacher and trainer, the creator of Body of Knowledge™ Anatomy and Biomechanics workshop series, Yoga with Resistance Bands classes, and a senior teacher and trainer at YogaWorks in New York City. Laurel is committed to raising the bar on the content and quality of yoga education. She teaches in order to help her students reclaim and strengthen a sense of power and belonging in their bodies, the bodies through which they share their gifts and transform the world. http://www.laurelbeversdorf.com

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Becky

So cool to learn something new like this! I have never heard of the Serratus Posterior before, as you say S.A gets all the attention but this is so fascinating and definitely worthy of recognition and respect.

Lindsey Rockett

Laurel, this is brilliant!

I have been a complete yogi with an incomplete understanding of yogic complete breath…until now! Thank you for breaking it down so intricately and with such inspiring imagery.

Jane Thibodeau

This post provides such a complete, concise description of the SPI and it’s function. I am one of those students who has heard a million times about the importance of the Serratus Anterior, but honestly knew nothing of the SPI, though I frequently do pranayamic techniques that I now realize incorporate it. Thanks so much for helping me understand the anatomy behind some of my favorite exercises. The wall/dresser analogy is spot on and really helps to clarify SPI function.

sue okuda

Fascinating read, so appeals to my anatomy nerdy side. I worked in a physical therapy clinic for awhile and got to observe the amazing PT in action. We always had students doing their PT internships working in the clinic. One day, the PT was working on a patient’s back and he asked the student, where’s serratus posterior inferior? The student didn’t know, so the PT had the student go look it up and report back. Thanks for giving this muscle some overdue recognition!

Sara

Wonderful post! You create such a clear and easily visualized picture of the function of the Serratus Posterior Inferior during Yogic Complete Breath. It has vividly clarified for me the technique of Abdominal – Thoracic Breathing. Your dresser/wall analogy is spot on!

Jennifer

Your dissection description of the Serratus Posterior Inferior deepens and clarifies my elementary understanding of what is happening when I breathe and how important this specific type of breathing is for the health and quality of my breathing. It’s as if you picking this one part actually helps me understand better the process as a whole. Your analogy is helpful because it is hard to understand that which is happening automatically in my body.

Michelle W

The complete analogy you offer here is so wonderful. As you talk about Yogic Complete Breath, it really helped me to further understand (and better practice) the ideas behind Abdominal-Thoracic Breathing. And I greatly appreciate the vivid analogy to help drive the point home. Wonderful post.

Caitlin Casella

The image of being wedged between a dresser and a wall is so helpful here. It helps me understand the leverage and power muscles provide by stabilizing a particular region of the body.

Tisha

This is so fascinating, and you always have the best analogies!! In all my trainings, I hear so much about the Serratus Anterior. I am a fan as I learned to roll the Serratus Anterior and Lats to help with a shoulder impingement I used to have. I’m becoming more and more interested in learning about muscles in the body that are either major parts of breathing or assist with breathing. It never occurred to me how being able to relax these muscles can actually help you breath better or are necessary for breathing. I did the YTU Yogic Complete… Read more »

Nick Shrewsbury

Wow! That is excellent information on the Serratus Posterior Inferior and on the process of taking a deep breath!I love the visual that helps to understand how the SPI stabilizes the spine and ribs during a diaphragmatic breath, allowing the diaphragm to increase the volume of the lungs. Thanks.

Allison Pfeiffer

Great explanation Laurel! This is a muscle that I didn’t know much about as far as function and how it helps during the Yogic Complete Breath. I am going to try this with a new purpose and understanding of my breathing capability and the importance of the “anchor”.

Natalie K.

I love this!! Cheers to the little guy. Thank you for explains Yoga Tune Up complete breath so well! It really helped me to understand the role of this muscle.

Maureen

Thanks, Laurel. This was brand new information for me. You were very clear on location and the example you gave made it much easier for someone like me, who is just learning about anatomy of my body, to picture and practice engaging. This will help my new journey into the importance of pranayama and working on the numerous breathing techniques to strengthen and create efficiency in my body.

Robin

I loved reading about the serratus posterior inferior and how it relates to yogic breath. This was such a clear and well described explanation. I am going tho put this into practice during my YTU training session tomorrow! Thanks Laurel!

Beth

Laurel,
Thank you for this insightful blog on the Serratus Posterior. I especially like how you talk about the role of the SP in yogic breathing and the use of your metaphor helped me understand a bit more about it. Perhaps it will help me become a better breather!
Blessings,
Beth

Therese

This may sound weird but, when I moved from a warm climate to a very cold winter climate. During sub-zero temperature days, I noticed I was restricting movement at the back of my ribcage and sometimes found breathing to be quite difficult. Thanks for bringing awareness to the Serratus Posterior via this article.

Marie Streich

I teach a three-part yogic breath in my classes, to teach people how to use their entire diaphragm to get more oxygen into their system. I never knew about the SPI function in regards to breathing so this is a great article for me , thanks !

Katy Loomis

Great article! The Serratus Posterior Inferior seems like a forgotten muscles so it’s great to read more about it’s function. Also, the Yogic Complete inhalation break down was very thorough and easy to follow. Thanks!

Riannon

Thank you so much for such a complete discussion of a rarely talked about muscle. You have rekindled my fascination with the yogic complete breath!

AnnMerle Feldman

This is an important redirect because I am one of those SA fan girls. Understanding how the diaphragm works in conjunction with muscles along the back of the body is a new and fascinating focus for my next studies.

Lauren Reese

Very insightful! Great information on a muscle that doesn’t get much attention in anatomy classes! Love your example of pushing the dresser! It gave me a great visual!

Jessie Dwiggins

Never mind its function, I didn’t know this muscle existed! Fascinating! And thank you for explaining it so perfectly with the wedge metaphor. I’m in YTU training right now and have questioned the context grids. This illustrates so perfectly why they are essential for relating obscure parts of the body to activties people understand. Brilliant!

Denise

Wow great information of a very obscure muscle

Allison Pfeiffer

Great article! Worked with this breathing technique in class today and I loved it 🙂

Michelle Officer

Thank you Laurel!
Nice to know the hard work my serratus posterior inferior has been doing all these years behind the scenes securing my ribcage and breath!
Those little guys definitely have earned some respect!
Also really appreciated the imagery in the refrigerator analogy!
Made its role so very clear to understand.
Will definitely have some new internal gratitude to be sharing in pranayama!

Eleanor

Really lovely explanation, I love the analogy of the wall and dresser! As a hands-on therapist, I frequently find very zingy trigger points in SPI, this is a nice way to explain it’s function.

Leslie

This article is a simply terrific explanation of the yogic complete breath and its phases. I am now much better prepared to present this idea to my students. I also especially appreciate the dresser and the wall metaphor–the image helps to explain the “stuck” feeling that eating an overly large dinner creates. . . and its effect on breathing.
Thanks!

Lorraine

A wealth of information on not only the Serratus Posterior Inferior, but also the yogic complete breath. I can feel this muscle as I breathe but you are right we don’t give it much attention. I have certainly done that furniture move before to budge an object that was too heavy to move. Next time I am in need of strong legs, core and a heave hoe breath, I will use the power of this muscle to get the job done.

Ilene

Thanks Laurel for this great pose and anatomy lesson on the Serratus Posterior Inferior! I loved the application to the Yogic Complete breath and I can now thank this superior muscle for enabling and enhancing the abdominal abode, so important for inducing the relaxation response. I also loved the picture with a reference to where it is located, attaches, etc, it was very clear.

Emill Kim

I loved your metaphor about how the diaphragm and the SPI interact. Have you ever encountered someone who an uneven build up one side of this muscle, particularly someone with one sided spinal compression. Curious.

Veronica

Laurel I like your article, and you’re right the serratus anterior is mention more, I hardly find in the anatomy book where the serratus posterior inferior is. Thank you for this full explanation and also it’s very clever your dresser analagy, love it!

Caitlin Vestal

Laurel, I love this post and this info about Serratus Posterior Inferior! Thank you so much for relating it to Yogic Complete Breath and for your dresser moving metaphor. This is one of those areas that I can always feel has less movement than I’d like it to in a pranayama like Yogic Complete Breath, and now I know one of the culprits! Thank you!

Jennie Cohen

Laurel, I think you’ve added to the canon of dog practices: we’re all familiar with down dog and up dog; introducing underdog! It’s so true that, as students of anatomy, we get obsessed with the major muscular actors and have a tendency to pass over the essential but less flashy little guys.

Marisa

When I first learned of the serratus anterior I was a fan of the muscle mainly because I found it aesthetically pleasing. Through yoga my affinity grew because of its importance in stabilizing the scapula and assisting in planks. I hadn’t heard much of the SPI. In YTU Level 1 training we learned Tubular Core and the importance of expanding and engaging the muscles circumferentially. Enter serratus posterior inferior. Its all making clicking now.

Steeve

Echoing the words of many of the responses above mine, I am compelled to say that your analogy of the dresser and the wall was absolutely fantastic.

That said, I just completed my YTU instructor\s Course where Mr. Serratus Anterior and Mr. Diaphragm were introduced to me. How lucky do you think I feel right now after having read your article?

Serratus Posterior Inferior. Thanks for helping me open my eyes to this muscle who plays such an important role on my breathing sequence.

As for my luck-meter. It’s reading a solid 10 on 10.

Ariana

Laurel, thank you for this fun and enlightening article! You are absolutely right- the Serratus Anterior gets so much attention these days. It’s nice to have some understanding of the SPI. You did a beautiful job and I think the analogy with the dresser is fantastic.

Kristen B.

I totally just had a different experience of my breath practicing along with the suggestions in this article. Can’t wait to get in there with the Therapy Balls and free up this muscle for more breath awareness. Thanks for the great info!

Jona Joyce

Super fanstic article! I love the detail and the analogy, really helps the visual. I gotta say as part of my breathing
practice I try to focus my mind into this area and imagine the action, it really helps me get a “full” breathe. ISP needs
more love, I totally agree.

Yelimar

Thanks for the insight. I just tried it in my own body. I never noticed what a big difference depressing my ribs would make on my breath capacity. I thought similarly to Kristen T. That’s so nifty! I have to spend some time with these muscles using the YTU balls. It seems that in all these years my brain never mapped out this area. I’m looking forward to building more awareness in my SPI.

Oliana

Laurel, you are so right on stating the lack of attention this muscle gets! I admit, I haven’t thought much about it, if not at all. Thanks for raising awareness and educating us about SP’s importance while doing yogic breath and how it affects the degree of movement of the diaphragm. I have to go to my mat and start say hello to my SP.

Andrea Borrero

always a bridesmaid … seriously, I’m going to give my SPI some love today as I breath and examine. I might have to use the dresser metaphor, as well. When you think about the pure form of SP and SA, they make this beautiful clam ‘reaching’ shape that just hugs the body in. Like two giant hands wrapping around either side of you, keeping everything in and formed.

Laurel Beversdorf

This is in response to Jennifer V’s question about a therapy to help with the injury to her Serratus Posterior Inferior muscle. Jennifer, check out this link for some Yoga Tune Up Quick Fix solutions to your injury http://www.yogatuneup.com/quickfix-yoga-videos. Particularly useful to you will be the Upper Body and Lower Body videos. The stretches you will learn are very simple and effective. Also, invest in a pair of Yoga Tune Up therapy balls, to do the self-massage exercises in the videos as well. In the meantime you can use tennis balls, but the YTU balls are MUCH better. You could… Read more »

Kirsten

So freakin’ cool! So, I just got down on the floor and contract my Serratus Posterior Inferior and did a Yogic complete breath exercise. I have honestly never taken that deep of an inhale before, by engaging the SPI I alway felt like my ‘core’ was engaging and therefore I thought less air would be able to come in, but the exact opposite happened – duh! Thank you for putting it into context ( love the dresser analogy) and bringing a bigger breath into my life.

Erin

Great information!! I also discovered a part in my back that gets locked when trying to complete this breath, and wasn’t able to conceptualize what/where was the culprit. Never even considered the serratus anterior as part of the equation.

Elizabeth W.

Today I discovered that my back body is so locked up that when I anchor my front ribs to keep them from flaring I can’t move at all. Thanks for illuminating the back body here. I see the work that needs to be done. More importantly, I can breathe more freely knowing that this work will help me breathe more freely!

Jennifer V

As a result of hitting the saddle badly while loping in Montana this summer, I pulled my Serratus Posterior Inferior muscles on both sides of my body. At first, the pain was excruciating and when I sneezed I saw stars. It’s now 6 months later and I am able to exercise and move freely but I am still experiencing pain and stiffness. Is there a therapy you can recommend? I stretch a lot, but I find that my sleep is not as good as it used to be because the muscles stiffen up while I am asleep and there is… Read more »

Prem

Thank you for this information! I DO talk a lot about the Serratius Anterior when I teach arm balances but will remember to bring the Serratius Posterior into the picture for complete breath

Jen G.

Thank you for your clear and interesting article about the serratus posterior inferior muscle. I think that the explanation you have provided here about this muscle could work just as well when talking about the quadratus lumborum and its role in respiration.

Roxanne

I am a new registered member on this YTU blog and this is my first blog!! (: The reason I have chosen to talk into this specific one is because a month ago I took Jill Miller’s Level 1 YTU Teacher Training Program and as part of my final exam, I had to write a minimum of 200 words about any muscle in the body. I chose the Serratus Posterior Inferior muscle and I just found it a coincedence that it was the first blog on the website as I started looking at it. I was able to add some… Read more »

Allison McCready

As a result of taking the Level 1 training at the end of this past summer, I fell completely in love with Serratus Anterior. Then I started hearing about it’s less famous cousin, Serratus Posterior Inferior and now here appears this lovely blog telling me all about the fantastical workings of the SPI! Hooray! As a flow yogi, for many years I was primarily interested in practicing and teaching Ujjayi Pranayama. Taking the YTU Level 1 training really opened my eyes to a whole new world of yogic breathing and also helped me to see the benefits of different types… Read more »