The Cobra at Your Core

The Psoas-Diaphragm Connection

By Thomas Myers

In the 21st century, we bodyworkers have been fairly obsessed with the concept of “core”—core strength, core support, core power. The transversus abdominis and pelvic floor muscles have been the focus of study for this core. The transversus abdominis is uniquely positioned to be supportive to the middle of the body—the lumbopelvic area where all the twisting and pumping forces we generate in daily life and exercise have to be handled.

The transversus abdominis belts around the waist, hugging the organs to the lumbar spine, stiffening the thoracolumbar fascia, and stabilizing the sacroiliac (SI) joint—quite a list of benefits for a toned transversus (Images 2A and 2B). This contrasts to what happens when the belly sags over the pubic bone, so that the organs pull the lower back forward and core support is lost.

The transversus abdominis is important for sure, but—being one belt for both sides—it can either stabilize both sides at once, or neither. Walking or running, for instance, requires that one side of the hip/pelvis complex—the SI joint in particular—be locked into force closure, while the other leg swings forward, unlocked and free. In the next step (in other words, every couple of seconds), this must reverse, with the free side closing into stability, and the formerly stable side unlocking into freedom.

This alternating stability and mobility from one side to the other could be called functional core support or dynamic core support, and it is a different animal that is going to require alternating tension in muscles other than the transversus abdominis and pelvic floor. “Oh, great, I’ve been toning my core for years now. Are you saying I have to strengthen other stuff?”

Yes. Such dynamic force closure and release of the SI joint is a complex process involving the tone and timing of the piriformis and gluteus maximus, as well as the abdominals, but here we want to emphasize a muscle complex that has gotten too little press in the gallons of ink spilled over this important concept of core support. That combination is the psoas-diaphragm “cobra” on either side of the spine (Images 1A & 1B).

Coupling the Psoas and Diaphragm

We will get to the anatomy and function of the cobra, but consider for a moment the centrality of the psoas and diaphragm.

• Both muscles attach to the front of the spine, right in front of the T12–L1 “universal joint” of the spine, where the strong flexion/extension of the lumbars meets the rotating T-spine with its floating ribs.

• Just in front of where these two muscles interface lie the kidneys (those ancient organs central to the definition of the self) with the adrenal glands (those moderators of alarm), sitting on top of the kidneys like rain hats.

• The coeliac or solar plexus, the largest gathering of your “gut brain,” also sits right in front of where these two muscles overlap.

• The diaphragm is the central muscle of breathing, and if you can’t breathe, as the saying goes, nothing else matters.

• The psoas is central to walking, perhaps providing the initial impetus for each step, and certainly providing a stabilizing support for the lumbar spine.

• The diaphragm is central to, and, to some extent, controls the functioning of the all-important vagus nerve.

• The movement of the thin, strong diaphragmatic membrane moves not just the lungs, but all the organs of the ventral cavity in a jellyfish-like movement—around 17,000 times per day, every day.

• The lumbar plexus of autonomic nerves sits within the muscle of the psoas major—the only autonomic plexus to lie inside a muscle. Thus, the health of your intestines can depend on the proper functioning of the psoas.

• The psoas major joins the top and bottom of the body, being one of the few muscles to join the axial and appendicular skeleton (i.e., the spine and the leg). Almost any imbalance in the legs or hips will require compensation in the psoas, which often gets transferred up to the diaphragm.

Ida Rolf would occasionally joke in class that the diaphragm is a muscle of walking and the psoas is a muscle of breathing, drawing these muscles together in our minds. These muscles are also frequent repositories for chronic emotional storage, as well as biomechanical adaptation.

For all these reasons, it is worthwhile to learn how these two muscles work together, and also how to contact and work with them (not “on” them), even though neither of them are close to the surface or easy to touch.

Note that both of them react negatively to being forced. I know, I am a student of Ida Rolf, and am no stranger to insistent attention to stubborn fascial adhesions. Rolf’s work was jokingly tagged as “massaging the spine from the wrong side.” Nevertheless, I am with Liz Koch, who appears elsewhere in this issue (“Wild Psoas,” page 72), in approaching the psoas with respect and compassion, giving it the delicacy and sensitivity one might use with the “highly intelligent” tongue, hyoid, or suboccipital muscles, not the direct pressure that is so much more productive in the gluteals or hamstrings.

The Anatomy of the “Cobra”

The psoas major muscle attaches to the lesser trochanter, on the inside of the “7” shape of the femur. Because it blends in with the hip joint ligaments that wrap the neck of the femur, we could start our cobra image with the tail of the snake coming around the head of the femur to wrap around the neck of the femur. It is a bit of an exaggeration of anatomy to wrap the snake’s tail a few times as we did in Image 1, but functionally, that’s how it works.

Then, like a cobra rising out of a basket, the psoas goes forward to cross directly over the front of the ball to stabilize the hip joint. It then crosses over the pelvic lip, only to dive behind the organs (retroperitoneal) to fill the gully between the transverse processes and the bodies of the lumbar vertebrae. You can often count 20 or so separate attachments for the psoas major when you dissect it carefully, with attachments to all of the bodies, discs, and transverse processes of the lumbar spine, often reaching up to T11–T12. 

In doing so, the psoas major interfaces with the posterior portion of the diaphragm. Most anatomy atlases scrape the fascia off, making a clean separation between the two, leaving little arcs of fascia along the bottom of the diaphragm, looking like the arcs of fabric between the ribs of an umbrella. We, the viewers of these clean anatomy pictures, get the impression that the two work separately.

In our Anatomy Trains fascial dissections, however, we find the psoas and diaphragm intersect where the “umbrella” of the diaphragm ties down into its stem—the crura that hold the center of the diaphragm down the front of the lumbar spine. When we pull manually on the psoas, the diaphragmatic dome on the same side changes shape because they are blending into each other intimately, fascially, and thus in transmitting the tension. It is only after you peel off all the connecting tissues that you get the “clean” separated picture we see so often in the atlases.

The hood and head of each cobra is each of the domes of the diaphragm, left and right, which connect to the psoai, left and right. In other words, there are two cobras, one on each side. The tip of each cobra’s nose rests right where the outside edge of your rectus abdominis crosses onto the rib cage, about the end of the 6th or 7th rib.

In anatomical terms, we have defined a cobra-like configuration that combines each psoas with its corresponding dome of the diaphragm. This two-muscle complex coordinates from our legs over the pelvic ring to the low back and breath. (Images 3A & 3B). Above this, the ribs and head take their cue from the angle of the diaphragm itself. Of course, this also involves the neck releasing, but right now we are focused on the balance from below.

A Happy “Cobra”

“OK, if I accept the image, how is it useful?”

How do we keep the cobra happy? Basically, the cobra is happy, healthy, and dynamic when it serves to:

1. Successfully stabilize the hip you are standing on, or temporarily riding over when you are walking or running

2. Release the leg that is swinging to reach forward for the next step

3. Keep the diaphragm in relationship with the pelvic floor muscles 

4. Balance the rib cage, neck, and head in easy equipoise above the low back

Points 1 and 2 concern stability in the SI joint. For simplicity’s sake, we will leave that for another article—it is highly complex, even for chiropractors and physiotherapists. Let us address points 3 and 4 here.

The ideal relationship between the respiratory diaphragm and the pelvic diaphragm is one over the other, as if you had one hand underneath a beach ball and the other hand on top of it (Image 4A). When we lose that relationship, we lose the power of “core,” and we subject the spine to more wear and tear, and possible injury.

Fashion models often drop the upper body behind the lower body, which disturbs that “hand over hand” balance between the two diaphragms (Image 4B). In that “heart-set-back” posture, the poor cobra does not function well. Part of the psoas goes into eccentric contraction, and part of it goes into concentric contraction; many other muscles and fasciae—notably the quadratus lumborum and thoracolumbar fascia—are involved in this pattern, so let us leave that one for a fuller treatment at a later time.

Postural twists in the spine, often called (but I hate the word) scoliosis, will also imbalance the reciprocal relationship between pelvis and diaphragm, as will side-shifts of the ribs on the pelvis.

To keep this article in bounds, let us consider two very common, not-so-functional patterns the cobra gets into in the sagittal (front-back) plane.

The first is when the cobra gets depressed. The psoas loses tone, the upper lumbar spine falls back, and the diaphragm—the nose of the cobra—falls in front (Image 4C). These people do not need you to poke around in their psoas; they need gentle encouragement to exercise the psoas to bring its tone up.

Wading in water up to your mid-thighs is an excellent way to tone a sagging psoas. Those without access to a pool or the ocean can tie a Thera-Band to a doorknob and their ankle, and tone the psoas by flexing the extended hip forward into mild hip flexion, while keeping the knee extended.

Gentle manual therapy to revivify the psoas can be helpful by restoring kinesthetic feeling to the psoas complex. Freeing the quadratus lumborum and lower-back fascia is a great help to them in creating the room for a strong psoas to function. But it is strengthening the psoas—the body of the cobra, so to speak—that will help lift the rib cage and head back to their supported, looking-straight-ahead position.

The second is when the cobra gets too enthusiastic, too toned. When the psoas has too much tone in it, the upper lumbars are pulled forward and the diaphragm leans back, lifting the nose and exposing the “throat” of the cobra (Image 4D).

These are the folks who could use a release, a relenting of the constant excess tension in the psoas. Such a relaxation will allow the rib cage to center over the pelvis, and drop the nose of the cobra back to its place of poise. What kind of work will allow this release? Different styles of work are effective with different “somato-psychologies,” so we can end this foray into core by inviting you to go to a class for one-to-one transmission of a mindful approach, not a blind application of “technique.”

Psoas-diaphragm balance is central core technology for the upright, breathing spine. It is fine and dandy that we are paying attention to the transversus abdominis and its contribution to spinal stability. Now is the time to take the next step inward to be able to see the condition of, and apply corrective exercise or manual release to, our inner cobra.