The Sacred Bone

The sacred bone. So here we have two sacrums. Sacrum is the bone that's in between your two hip bones or ileum forming the sacroiliac joints which you might have heard a lot about. Yoga teachers are pretty fond of talking about the sacroiliac joints. Sacrum comes from the Latin a sacrum meaning sacred bone and one thought of the reason why it might be termed that is that they would find these sacrums on altars as an offering for fertility or abundance because right in front of our sacrum is our regenerative organs our uterus and and fallopian tubes and this is where we kind of birth any new project so this sacred bone is actually four to five fused vertebra so if you imagine taking those individual vertebra and kind of melting them down in the microwave it would have this kind of appearance of getting kind of fused together so you can see almost like they've been squished together. Now you can see some of the spinous process what remains in the transverse processes but it has this kind of pyramid shape to it or triangular shape with the point facing down. Now here we can see there's four fused vertebra and we're all very unique so in the books they usually say four to five fused vertebra make up your sacrum. Your sacrum shows up differently in the spectrum of genders. I used to very much talk about gender as a binary so a boy pelvis and a girl pelvis. As we're learning in anatomy and in the world it's not so cut and dry or black and white it's more of a spectrum but there are some gendered differences in the sacrums so closer to a female sacrum or what we call in anatomy world a gynecoid sacrum we can see it's wider and kind of more squat and this is because our pelvises are a little bit wider and so it has to kind of cross this expanse. In a male sacrum or closer to what's called an android sacrum you can see it's more kind of tall and narrow and here we have a male sacrum or an android sacrum and you can see still four fused vertebra. Now on the male sacrum we can see they're attached as his coccyx bone or tailbone. In the anatomy books it says that this is like three to four fused vertebra but you can see on him he has two fused vertebra and maybe the little beginnings of a third one here so we're all extremely unique. We turn the sacrum to the side which is how it sits in the body right and in between your two hip bones. If we view it from the side you can see it has that kyphotic curve. If you compare the two you can notice the gynecoid or the female sacrum a little bit more curvy. The male sacrum a little bit more linear a little bit taller thinner and less curvy. Another difference that we can see is the articulation where it articulates with the two halves of the pelvis. This articular surface on the male it attaches at three segments on either side. On the female it attaches at only two segments on either side. Thusly the female sacrum has a little bit more give a little bit more mobility, males a little bit more stability. It's kind of this natural yin-yang balance where you have more mobility less stability more stability less mobility. Because of this women tend to show up with a little bit more movement and a little bit more injury in their sacroiliac joints. There's a little bit of a debate in the anatomical and yoga community about if the sacrum actually is supposed to have independent movement from our two hip bones. We can all agree it goes for a ride when our pelvis moves. So as we kind of do a little Elvis pelvis stance our sacrum will nod its head which is called nutation and it'll counter-nutate. So as we take something like a cow pose where we arch the spine doing a back bend the sacrum will nod its head towards the front of the room or towards your belly. That's called nutation almost like a way to take off a hat nod towards you. When we do a cat pose we round our spine and we take flexion in the back. Our sacrum moves its head back into counter nutation. We all kind of agree that that's what's going on back there but there's some debate whether it has independent movement from the two halves of the pelvis. The ones that say that it does indeed have a little bit of movement will say well only has a couple of degrees of movement which is pretty minute pretty tiny. My opinion is it has it's meant to be this kind of fulcrum between the torso and the whole upper body and the legs. It's meant to be an area of stability and strength and support and so we shouldn't ask for a lot of torque or twisting or individual movement where maybe none exists. Unfortunately we do this when our teachers ask us to plant our sitting bones into the floor and rotate or keep our hips square as we take something like a revolved triangle pose or a lunge into a twist. My opinion is that we can allow it to have a little bit of give or sacrifice a little bit of the depth of the pose to save us from the sacroiliac instability and pain, long-term pain that shows up when that injury shows up.