Your sacrum is a small bone at the bottom of your spine that looks like an upside-down triangle. Caught in the middle of your two massive hip bones, the ilium, it's really at the mercy of the muscles and bones that surround it. Stretch too far or suffer a hard fall and the sacrum can shift out of its place. Unfortunately, you can't stretch it back into place; there are specific re-positioning exercises for that. You can, however, jumpstart your recovery process with a few stretches.
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Suppose you're stretching, reaching down to touch your toes or even the floor, and you hear a sudden "pop!" You do a quick body scan to see if you feel pain anywhere. Unlike a disc herniation or bulge, with an injury to your sacrum you'll probably only feel a dull pain. Instead of radiating down into your leg like some back injuries, a sacrum injury will hurt right in the area of the sacrum, the lowest part of your spine.
Read More: The Best Stretches for Sacroiliac Pain
The sacrum sits between the two big hip bones on either side of your hip, called the ilia. These massive bones give your hips their structure, and connect the spine to your legs. The sacrum is actually made up of five vertebrae that fuse together between age 18 to 30. The coccyx, or "tail bone," is located under the sacrum, and is made of three to five vertebrae that naturally fused together. There is a joint between the sacrum and the ilia, called the sacroiliac joint, or SI joint.
There are a few different ligaments -- bands of connective tissue that connect bones to other bones -- that connect your ilia to your sacrum. The first is the sacroiliac ligament. There is also the sacrospinous ligament and sacrotuberous ligament. All three anchor the sacrum and the ilia together, preventing them from moving too far away from each other.
If you stress these ligaments too much, they can stretch out or tear completely, allowing the sacrum to move away from the ilium. While this isn't going to ruin your ability to exercise forever, it's painful enough to force you to take a few days or even weeks off from exercise.
An injury to the sacroiliac joint typically happens from a forward-bending motion, like a toe touch. It can also happen if your leg is rotated out too much, like in a seated butterfly. Women have a higher incidence of sacroiliac joint injury than men do, possibly due to a hormone called relaxin, which makes ligaments slightly more elastic in women.
Usually just one side of your sacrum moves out of place, not both sides. That's because an asymmetry generally causes an injury to the sacroiliac joint. A leg length discrepancy, which means that one leg is shorter than the other, is an example of an asymmetry. If one leg is longer than the other it will shift your hips to one side and put more pressure on one side of the sacrum. That's why part of sacroiliac injury rehab is making sure both hips are symmetrical.
Read More: Exercises to Strengthen the Sacroiliac Joint
To rehabilitate a sacrum that moved out of place, you can try stretches that don't hurt or injure it further. You'll want to avoid forward-bending stretches and stretches like the butterfly or pigeon pose that rotate your hip out and move the sacroiliac joint. You also need to work on making your hips more symmetrical, which you can do with a simple breathing drill.
Hamstring Stretch on Wall
The exercise allows you to stretch your hamstrings without worrying about rounding your back.
How To: Lie on your back next to the corner of a wall. Keep the leg on the side of your sacrum that isn't injured on the ground. Raise the leg of the injured side up into the air and place it against the wall. Keep your knee as straight as possible. Hold the stretch for 20 to 30 seconds, then switch sides.
If your hip flexors are tight they pull on your ilia, which can stress the sacroiliac joint. Stretch out your hip flexors with this exercise.
How To: Stand at arm's length away from a wall. Brace one hand on the wall and, with the other hand, grab your ankle and pull your foot in towards your butt. Hold for 20 to 30 seconds, then switch sides.
90-90 Leg Lift
This exercise will help you correct asymmetries in your hips and sacrum, taking pressure off of the injured side of your sacrum.
How To: Lie on your back with your feet on a wall. Your hips and knees should be bent at a 90-degree angle. Breathe in through your nose and breathe out through your mouth. As you breathe out, dig your heels down into the wall and flex your hamstrings. Then, shift your hips so that your left knee is lower than your right knee. Take another breath and lift your right foot off of the wall. Complete three breaths, then relax.