Lately, I’ve been trying to systematically start to get a grasp around some of the complexities of the body that become apparent when deepening one’s yoga practice. First on my plate is the SI Joint and Yoga; understanding the sacrum and its movement at the sacroiliac joint (SI or SIJ). Of course, this is just an initial review making use of cutting and pasting from my overstuffed bookshelves and files. There will be some generalizations, simplifications, and errors in understanding, but I hope provocation to those more knowledgeable than me to provide clarification. So, onwards we go.
As we begin practicing yoga and learn how to move the spine, we are mostly concerned with gross actions like folding in, or opening up. Eventually, we might pay attention to pelvic tilts that help move the spine safely and effectively, but as we dial down into further detail we can pay attention to the subtle and refining actions of the sacrum and SI joint. This is also a hotbed for injury and yoga opinions for best practice and prevention.
What is the sacroiliac joint and how does it work in our body?
Shape and function
The sacrum is the “posterior, wedge-shaped component of the pelvic ring, located between the two ilia.”The sacroiliac joint consists of “two auricular surfaces on top of the ilium and the sacrum”(Calais-Germain, 2007). In function, it is the “conduit for force between the legs and torso and the meeting point of the pelvis and spine – sixty percent of the body weight goes through the sacrum giving us some idea why this bone is so massive” (Farhi, 2012). When standing, it locks in place “similar to the way a padlock closes”creating a firm foundation for the spine (Lasater, 2008). Important to understanding potential dysfunction and prevention, the SIJ has a reinforcement system of ligaments (Calais-Germain, 2007) and its only direct muscular connection is the piriformis but it has “inferred muscular support systems”throughout the numerous muscles of the core (Farhi, 2012).
The SIJ has two fundamental movements: nutation and counternutation (Calais-Germain, 2007). It might be easier to think of it as nodding forward (nutation) and nodding backwards (counternutation). SI movements are “literally the only movements permitted between the axial skeleton and the appendicular skeleton for the lower extremities” (Coulter, 2001). Donna Farhi explains these two movements and their subsequent effect across the rim and base of the pelvis in the everyday function of walking:
There is a natural slight swinging under of the joint in normal walking movement or when we lift one leg as in marching. This is called counternutation of the SI joint. In counternutation, the base articular surfaces of the sacroiliac lock and the top of the SIJ flares or gaps. When we bear weight on one leg and draw the other leg through (as in walking) or in back bending movements the joint moves forward and up, a movement called nutation. In nutation the superior articulation surfaces of the SI lock while the base flares and opens. In a twist one side of the sacrum is in nutation while the other is in counternutation, giving us some idea as to why twisting can be a culprit in both causing and exacerbating SIJ dysfunction. (Farhi, 2012)
Roughly, nutation is usually experienced as part of a pelvic tilt forward and can be felt in the sensation of one’s sitting bone’s spreading apart and counternutation is usually experienced as part of a pelvic tilt backward and the sensation of sitting bones joining back together with an accompanying spread near the waist. However, these are subtle actions. Most people over the age of 25 have restricted movement in this region. Older men may have completely fused SI joints. However “athletic young women are notable exceptions; their sacroiliac joints are generally more mobile than men in comparable condition” (Coulter, 2001).
Men and Women
It is important to understand the difference between the sexes in bodily construction and experience within this specific region. In general, women have a wider pelvis and two articulating surfaces at the SIJ and men have a narrower pelvis and three articulating surfaces – simply, men are more stable in the SIJ and will experience it differently. In addition, giving birth, hormonal changes during menstrual cycles and menopause can also cause additional movement, dysfunction and ligamental laxity within the SIJ (Farhi, 2012).
How does the SIJ work in a yoga practice?
Since SI movements are so small (5-10° except during the end stages of pregnancy), most textbook description is limited to pelvic and spinal movements. However, the subtle and refining actions of nutation and counternutation make for “safer, sharper postures.”Furthermore, “the proper execution and full expression of backward bending, forward bending, and seated meditation postures presupposes the ability to establish nutation and counternutation at will”(Coulter, 2001). In general, forward bends favor nutation, backbends with a pelvic tilt backward for lumbar safety favor counter-nutation, although backbends can occur in those with healthy back with some nutation to encourage lumbar curvature. However, like anything, a student can overdo nutation or counternutation relative to the movement of the pelvis and spine and create strain or overstretching. Frustratingly, there is no proof available for the amount of SIJ movement in yogis and its relation to pain and dysfunction, however there is some related medical evidence from non-yoga patients creating a correlation between SIJ movement and back pain (Cole, Protect the Sacroiliac Joints). Beyond the simpler-to-understand act of overdoing a basic symmetrical nutation or counternutation in backbends or forward bends, is what happens when poses are asymmetrical or revolved. This is where discussions start to get heated.
How can things go wrong in the SIJ?
Cole explains that “many health professionals who have worked with yogis believe that the cause of their SI pain is excessive movement of the joint, leading to misalignment, ligament strain, and, possibly, eventual deterioration of the cartilage and bone on the auricular surfaces.”Simply, there are two theories as to dysfunction: 1) misalignment of the joint 2) overstretched and strained ligaments. These two theories can of course overlap. Regardless of the end result, the beginnings of dysfunction can be created many ways. Seated asymmetrical forward folds like Janu Sirsasana are a major culprit in creating an uneven experience of the sacrum “too far forward on one side of the body relative to the ilium” resulting in either joint misalignment or ligamental strain depending on which theory you adopt. Additionally, this unevenness can happen in symmetrical forward bends if a student has asymmetry through their body such as one hamstring tighter than another. (Cole, Protect the Sacroiliac Joints)
Lasater posits that “SI pain is a result of stress at the joint created by moving the pelvis and the sacrum in opposite directions”(Lasater, 2008). Farhi explains further that instability arises “primarily through practicing postures in such a way that the pelvis is forced to move as THREE separate units instead of ONE integrated unit.”For example: forcing oneself into huge hip opening postures past one’s end range of movement and effectively using the femur as a lever to pry the two ilium apart from each other unevenly, jamming back into the SI joint. Lotus can be a culprit, or wide legged standing postures where the hips face the long edge of the mat and the back foot faces the back edge instead of turning in to some degree. All of this can contribute to ligamental laxity, which combined with poor core strength can create sacroiliac instability. Farhi favors creating a “stable mobility”within the SI joint with precise alignment, moderated mobilization, and regional muscular support. (Farhi, 2012).
Yoga Practice and the Sacrum
There are numerous and sometimes contradictory opinions on how to both prevent and counteract SIJ dysfunction. Generally, there is agreement that yoga can be as much therapeutic as it can be detrimental to the joint if practiced carefully. We shouldn’t be afraid to move the SI or work with its flexibility, as it is important in basic function as walking, sitting, and standing. Asymmetric poses can even relieve asymmetric tightness through the joint for healthier function. (Coulter, 2001). Lasater has found that “creating stability is the key to preventing overstretching and thus remaining pain-free in the SIJ” and the best poses for SI pain are twists and asymmetrical forwards bends, both of which help to diminish the torque through the joint. Strengthening the muscles around the SIJ so as to prevent future problems can be accomplished by practicing simple backbends and standing poses (Lasater, 2008).
Precise alignment instructions are beyond the scope of this investigation, but here is a sampling of general advice.
Move as one unit
The dominant discussion of SI safety and pain prevention focuses on keeping the sacrum, ilium, and lumbar spine functioning as one unit.
Keeping the hips square to the long edge of the mat and the back foot parallel to the back of the mat in poses like triangle or side angle can combine abduction with side bending in a way that “pulls one side of the sacrum forward of the other,” which may “create a gap in the joint on one side and a jam in the other” (Cole, Protect the Sacroiliac Joints). Simply, it creates three moving parts instead of one. This is why many teachers now advise turning the back foot and hip in to some degree so that the ilium aren’t being pulled in opposite directions while simultaneously supporting a complicated bending action above, as many standing poses demand. In seated wide-legged positions such as Baddha Konasana or Upavishta Konasana, more abduction of the thighs isn’t necessarily better as this can provide similar pulling apart of the ilium that combined with a forward bending action can spell trouble. A smart student should probably make sure thighs feel secure into the socket without strain into the back before initiating any further movement. Farhi advises that safe hip opening demands keeping pelvis stable while exploring range of motion in the hip joints (Farhi, 2012).
Twists can be major villains in the SIJ discussion. Especially revolved triangle, and seated twists. Building off of her focus on stability, Farhi advises that twists be initiated in a way that â€œthe pelvis, sacrum and lumbar spine are all in agreement about the direction in which they are turning. Any twists where the pelvis is fixed and the lumbar spine forced beyond its normal range of rotation (for instance by strongly levering the twist with the arm, or through aggressive adjustment by a teacher) has the potential to damage the lumbar spine and sacroiliac joint. Farhi advises allowing the hip to turn with the twist, instead of maintaining a fixed pelvis, so that in a pose like revolved triangle the back hip turns in the direction of the twist. Similarly, in seated twists, one hip moves slightly forward on the floor to begin the twisting action in the hips and then progressively up the spine (Farhi, 2012). Additionally, arms should not be used as strong levers. Lasater teaches that it is “better to create as much of the twist as you can before using your arm as “this will decrease the possibility of separation and strain at the SIJ” (Lasater, 2008).
Cole advises that “when the pelvis stops tilting forward in a forward bend, [one] should also stop moving the sacrum forward and bend cleanly at the hip joints, rather than letting the body bend half way between the lumbar spine and the hips” and in twists “when the pelvis stops turning, the remaining twists should come not from the SI joints but from rotation higher up on the spine and trunk (that is from joint movement of the thoracic vertebrae and ribs, facilitated by release and stretch of the surrounding muscles.”(Cole, Practice tips for the SI Joints). This idea of rotation higher up the spine away from the slightly troublesome SIJ leads us into another proposed way of working in this region.
To confuse us, not everyone agrees with the above approach or its logic of moving as one unit. As an alternative to creating subtle shifts of slightly turned in feet or rotated hips within otherwise traditional postures, some teachers now advise taking an even further modified approach to standing poses. Culprits like side angle or triangle can be modified to have more width in their stance (gap between heels rather than heel to heel or heel to arch alignment, as well as the back foot turned in significantly) to maintain more space across the sacrum and rotational capability within the hip sockets. These poses are experienced more as a thoracic twists above a spacious and supported sacrum rather than a side-bend that potentially sends stress unevenly into the SIJ. Revolved Triangle retains the previously vilified fixed hips, but the spine is encouraged to lengthen more upward to allow axial extension and an incremental twist centered more in the thoracic spine. Conversely, if this pose was practiced with a goal of grabbing the toe, there would be a high risk for flexion and rounding through the spine and compression and unhappy movement through the lumbar and sacral regions. An upward draft to the pose encourages space and stability through the SIJ and allows for twisting without strain below.
In a stronger viewpoint, teachers such as Michaelle Edwards advises doing away with most these risky twisting poses (Edwards).
The individual approach
Starting to lose your mind contemplating this complexity? Join the club. There are contradictory viewpoints strongly offered suggesting that each provide relief from pain. The proponents of these viewpoints have direct experience. Both cannot be wrong, and rather the differing viewpoints point to a variety of options and choice. I propose trying out different techniques and seeing what works best. Move from a place of consciousness and stability through the core and pelvis, avoid extreme openings and movements, and keep a sense of space and evenness through your joints. As Jason Crandell observes in the knowledge that different people will respond to different techniques: “If you’re doing something and your SI pain increases, that is not a good thing to do for your SI. The best way that you know that an SI adjustment or modification is working is that the sensation decreases”(Crandell, 2012).
The bibliography below offers great resources for further reading and tips for practicing for prevention of SI injury or relief. If you see errors in the above or more to be added, please comment.
Calais-Germain, B. (2007). Anatomy of Movement: Revised Edition. Seattle: Eastland Press.
Cole, R. (n.d.). Practice tips for the SI Joints. Retrieved February 19, 2014, from Yoga Journal: http://yogajournal.com/for_teachers/1028
Cole, R. (n.d.). Protect the Sacroiliac Joints. Retrieved February 19, 2014, from Yoga Journal: http://yogajournal.com/for_teachers/1027
Coulter, H. D. (2001). Anatomy of Hatha Yoga. Honesdale: Body and Breath.
Crandell, J. (2012, October 19). Yoga Relief for Lower-Back & SI Pain. Retrieved February 19, 2014, from YogaGlo: http://www.yogaglo.com/online-class-2070-Yoga-Relief-for-Lower-Back–SI-Pain.html
Edwards, M. (n.d.). Yoga Twists and Turns: How to Stay Safe. Retrieved February 19, 2014, from Yoga Injuries: http://yogainjuries.net/twists_turns.html
Farhi, D. (2012). Coming Together: The Sacroiliac Joint.
Lasater, J. (2008, September). Out of Joint. Retrieved February 19, 2014, from Yoga Journal: http://www.yogajournal.com/practice/2871