Understanding the Sacroiliac Joint

article migration image 217 understanding the sacroiliac joint jpg

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.

Happy Sacrum

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.



Yoga Anatomy: Avoid Hand and Wrist Injuries

human hand anatomy

Think of the number of times your hands and wrists are connected to the earth and carry your weight in a typical Hatha Yoga practice.  Like our feet, our hands frequently become a crucial foundation from which our postures build and express themselves.  Sustaining mindful engagement of our hands will support a life-long practice that is free of negative stress conditions and injuries to the wrist.  Let’s look at some anatomical aspects to give us empowerment and motivation to explore our unique positioning and engagement of the hands and wrists.

The wrists are formed by our 2 forearm bones (the radius and ulna).  They meet dat the wrist joint where there is cluster of small bones (carpal bones).  The carpal bones connect with 5 long bones (metacarpal bones) that make up the palm of the hand.  From there, the metacarpal bones connect to the bones of the fingers (phalanges). The carpal bones form a tunnel through which tendons and nerve tissue pass to service the hand and fingers.  One primary focus of hand engagement is to avoid collapsing into this tunnel and keeping excessive pressure from cascading into that track of muscle and nerve tissue.

One primary focus of hand engagement is to avoid collapsing into this tunnel and keeping excessive pressure from cascading into that track of muscle and nerve tissue.

Another key structural area to consider is the joint connection between the ulna and the carpal bones.  If you turn your hand open (supination of the forearm and wrist), your ulna is the inside forearm bone (medial side).  Unlike the radius (lateral or thumb side) that has a direct joint connection to the carpal bones, the ulna has indirect joint connection.  Instead, there is a piece of fibrocartilage (designed to absorb stress forces) between the ulna and carpal bones along with a network of supporting ligaments – this area is called the Triangular Fibrocartilage Complex.  When we look at the overall differences in joint connection, the radius also has a larger joint surface compared to the ulna.  This gives indication that most people are best served to deliver a greater proportion of their force and energy through the radial side of the wrist than through the ulnar side.

Read Article

More In Focus

Our unique blend of yoga, meditation, personal transformation, and alternative healing content is designed for those seeking to not just enhance their physical, spiritual, and intellectual capabilities, but to fuse them in the knowledge that the whole is always greater than the sum of its parts.


Use the same account and membership for TV, desktop, and all mobile devices. Plus you can download videos to your device to watch offline later.

Desktop, laptop, tablet, phone devices with Gaia content on screens

Discover what Gaia has to offer.

Testing message will be here