Understanding the Sacroiliac Joint
Asana Anatomy-Understanding the Sacroiliac Joint
Controversy does not often strike the yoga community. Non-harming, truthfulness, and loving kindness are not very controversial concepts. Yet the poor, barely mobile, sacroiliac joint has become the center of a yoga debate – to square or not to square the hips. Ok, so it is not as racy as a celebrity feud, but it may affect your personal yoga practice.
Let’s dissect this joint.
The two sacroiliac joints (SI joint) are formed by three bones: the triangular sacrum bone, and the two wing like bones of the pelvis known as the ilium. Each iliac bone (one half of the ilium) comes in contact with one side of the sacrum, forming two SI joints. This connection is like three puzzle pieces fitting together known as form closure. Form closure creates stability, keeping the pelvis together in one unit. The SI joint itself is shaped like a boomerang with two arms at 90 degrees to each other. The upper portion lies in an up-and-down orientation and the lower portion lies in a front-to-back orientation. The surface of the joint is covered in coarse cartilage, adding friction and contributing to the force closure.
The sacrum moves in nutation (forward) and counter nutation (backward) in relation to the ilium. The sacrum can move only on one side, like in lifting one leg, or both sides, like when we move from lying to standing. This movement is very small, amounting to 1 or 2 mm of motion in either direction. As we age, the sacrum becomes wedged increasingly forward, but this doesn’t fully happen until we reach our 30’s. This wedging increases the resistance to shearing (twisting) forces across the sacroiliac joint. Herein lies the problem. The SI joint is a joint that is intended to provide stability for the pelvis, and is not built to move.
The SI joint has another mechanism of stability – force closure. This is the stability created by the action of the core musculature that has attachments into the SI joint – namely, the muscles of the pelvic floor, and the transverse abdominis. Conveniently, we can access these muscles through the activation of the bandhas or energy locks in yoga. In mula bandha we imagine a subtle lifting up of the muscles we use to control the flow of urine. In women, activation of this musculature has been shown to provide force closure for the SI joint. In uddiyana bandha, we draw the lower belly in and up, activating the transverse abdominis muscle. For this version, the scooping of the lower belly needs only to be subtle, and slightly flattens out the lower abdomen.
Hip Opening or Sacroiliac Opening?
Many of us identify ourselves as having “tight hips”. For many, this means a lack of external (outward) rotation at the hip joint. Using the example of Virabhadrasana I or Warrior I pose, our front hip is in a flexed position with toes pointing straight ahead. Our back foot is on the floor at a 45 degree angle, and in order for the points of our hips (our iliac crests) to face toward the front of the mat, our back hip needs to extend, and externally rotate. If we look deep inside we see that these actions require our sacrum to nutate forward on the side of the lead leg, and counter nutate backward on the side of the rear leg. If the rear hip resists external rotation in order to square the hip points forward a twisting or shearing force is introduced across the SI joint. Over time this can lead to irritation, hypermobility, and dysfunctional firing patterns of our pelvic musculature.
This situation is an opportunity to practice ahimsa or non-violence towards our SI joints. There are a few ways you can diminish the shearing force across the SI in standing poses. The first is to take a slightly wider stance, opening your feet to hip width (rather than heel to arch or heel to heel). This enables your pelvis to comfortably square forward. Another option is to keep the feet as they are and simply allow your pelvis to be slightly open to the side of your mat. That’s right, let go of the desire to perfectly square your pelvis forward. Instead, imagine the hip bone in its socket, outwardly rotating. Keeping that rotation, tuck the tailbone under slightly, creating room in the front of the hip. You may find that this provides more freedom of movement and may naturally square your hips further. In standing and seated twists, be sure to engage the muscles of the pelvic floor (mula bandha) to support the SI joint before twisting.
When we step back for a moment and acknowledge the true purpose of our yoga practice, suddenly trying to make our bodies fit a mold doesn’t make much sense. Being more forgiving and accepting of our bodies limitations enables us to go much deeper into our yoga practice and experience the joy of yoga safely. Now that doesn’t sound controversial at all.
Standing Tall: Why Posture Matters
Remember how your mom used to always lecture you to stand up straight? Well, she might have made some mistakes over the years (that outfit in your 5th grade school picture), but on this one, she’s right. Posture matters more than you may think.
First, let’s talk about your body, starting at the top. Each inch your head is forward of your shoulders doubles the amount of weight it puts on the rest of your body. Although the average head only weighs between 8-10 pounds, your upper back (and then lower back and hips) will become misaligned if your head “lives” in a forward position – all in an attempt to balance your now-too-heavy head.
And, unless you sit in an ergonomically perfect workstation, chances are you round forward over your keyboard or laptop like something straight out of the latest episode of the “Walking Dead.” Most of us, sadly, are in the process of developing this posture. Blame the Internet (we’re talking to you, Mark Zuckerberg) or your boss (for making you work too much).
What happens to our bodies? Back pain, neck pain, hip pain and knee pain. And, let’s not forget your breathing. Collapsing forward compresses your lungs, reducing their capacity by 30 percent or more. Your organs can’t function properly, and neither can your muscles, joints, or connective tissue.
Posture also matters for your mental health. Good posture allows you to breathe more fully, calming your nervous system, which can help with everything from good sleep to good moods. Plus, standing up tall makes you feel more confident. Slouching pulls your energy downward, even making walking and balance more difficult.
What to do? First, analyze your own posture. Do your shoulders slouch? Is your head forward? Do you have back or neck pain? When you walk do you have a tendency to lean forward and feel like you’re lifting your knees towards you?
Since it is vital to have extension in the upper torso in standing posture, the starting place is simply awareness of how you’re standing or sitting. Imagine lifting out of your pelvis, shoulders back, head looking slightly above the horizon.
Don’t spend too much time sitting at your desk, especially in bad posture. Take a walk. Inhale your arms overhead and slightly back. Regularly engage your lower trapezius to draw your shoulders away from your ears, and your rhomboids to draw your shoulders together.
And balance the forward posture with a lot of back bends. Stretch your pecs and anterior shoulder muscles with anahatasana pose (think child’s pose with your hips over your heels, reaching your tailbone and chest away from each other). Camel pose has been called the “antidote to sitting” because it stretches the entire front of your body.
If you have access to a Pilates reformer, you’re in luck. Do seated arm circles to take your shoulders through a weighted stretch, and turn around for chest expansion to, well, expand your chest and your lung capacity. Or just lie down on a mat, extending arms and legs long on the floor, and lift up, fluttering arms and legs in opposition while breathing deeply.
Most importantly, throughout your day, remember to stand up straight. Don’t slouch. Just listen to mom on this one. You can still argue about your clothes, your politics, and what’s for dinner. On posture, she’s right.