1. It is very normal to collapse onto one leg while standing. For example, if you were talking to someone and you straightened and put most of your weight on your right leg and stuck your right hip out to the right with a little bend and barely any weight on your left leg. This will cause the right side of your sacrum to push back (because you are collapsing on that hip), this backward pressure and rotation on your right SI joint to go out and get stuck. When I say get stuck I mean your sacrum will be “stuck” is this rotation and will keep the sacrum turned at an awkward angle.
a. How to identify which way your pelvis is rotated: lie on your back, with your knees bent in and your feet on the floor. Gently flatten your lower back to the floor. Keep your feet on the floor and slowly bring your knee to the right, and then a few inches to the left. Feel for a knobby place (the PSIS, Posterior Superior Iliac Spine) around the back of your pelvis. The side where the knob feels the most dominant is the side to which your pelvis is rotated.
i. You can help correct this misalignment with the first universal principle of Anusara yoga which is open to grace. When we talk about the first principle we are also talking about the inner body. If your pelvis is rotated away from optimal blue print so if your inner body. To correct this turn your inner body away from the side that you pelvis is rotated, and this may feel very imbalance it is actual balanced and neutral. Having the misalignment in the sacrum has re programmed your body to what “neutral” is however the body is wrong and this new "neutral" is continuing to move the body farther and farther out of alignment. By turning your inner body way from collapse you can “re program” the body so the sacrum is facing straight ahead. Whenever we talk about principles it is important to remember that we are always practicing a combination of the 5 so even though I am emphasizing the open to grace in this situation you still want to do everything else as well. For example if you don’t work muscle energy, engaging the muscles then you can’t maintain the position of the inner body.
Asymmetrical Poses where one leg is forward and one is back (lunges, parsvakonasana, parsvottanasana, virabhadrasana, Trikonasana…): in all of these standing poses you want to create that neutral pelvic bowl. Do this by balancing out the outer spiral (scooping the sit bone) of the front leg and inner spiral on the back leg. It’s an asymmetrical pose, so the sacrum will need to tip in and up faster on the back leg side, while it will need to go down and in faster on the front leg side. You can take your hand to your low back and feel the sacrum to make sure it is going in and up, you should have an even lodorsail curve in your back. If the curve is really big lengthen your tailbone toward the earth so the low belly engages.
Sitting poses and forward bends (sukasana, uttanasana, janusirsasana, upavista konasana): for all forward bends, the top of the sacrum must draw in and up before moving past 90 degrees in the pelvis. This is a crucial alignment for the health of the lower back.
Symmetrical poses where the feet are in one line (Ustrasana, tadasana, utkatasana): as a symmetrical pose, this is a really great way to realign the sacrum/pelvis. Use your inner body to balance the rotation of the pelvis. Inner spiral the thighs and emphasize this on the side that the sacrum is rotated toward. Then apply outer spiral and emphasize this action a little more on the side that the sacrum is rotated away from. So to continue our example from above, you would inner and widen your right sit bone out a little more, and you would scoop your left sit bone under a little more.
Prep for shavasana: bend your knees and put your feet on the floor knees over ankles and isometrically draw your heels back toward your sit bones which will create a lodotic curve in your back. Keep the curve as you straighten one leg at a time toward shavasana
Yoga nerds notes by Zhenja
Yoga as Therapy, By Doug Keller):
The Anatomy coloring book, by Wynn Kapit and Lawrence M. ELson