Is Your Chiropractor Adjusting You Wrong?

Most people who visit a Greenville chiropractor are familiar with a side posture chiropractic adjustment intended to correct or mobilize the sacroiliac (SI) joint. Side posture adjusting is one of the most common types of a chiropractic adjustment performed. However, the science and research behind this adjustment do not support the assumption that the side posture adjustment is actually capable of mobilizing and thus adjusting the SI at all.

This is a rather advanced topic but bare with me and you will end up understanding more about the SI joint than practically any MD and most doctors of chiropractic in Greenville and the rest of the country.

The Sacroiliac Joint Is Not Designed For Movement.

The primary function of the SI joint is to transfer load from the upper body to the lower body. This is evident when you look at the design of the SI joint.

1. There are NO muscles that cross the joint to act as movers. I.e. your elbow has muscle that attaches above and below the joint both on the front and the back. The biceps flex your arm and the triceps extend it. No such muscle exists that solely crosses the SI joint by attaching from the sacrum to the ilium to close or open the joint.
2. The SI joint is surround by numerous ligaments to create more stability by holding and compressing the SI joint. These ligaments are the largest and strongest in the human body. There are some muscles that attach to the ligaments and when activated will compress and stabilize the SI joint but none that actually mobilize the joint.
3. The sacrum and the ilium come together at the SI joint. The sacrum is a propeller shaped wedge that fits in place between the two ilia. When you stand the weight of your body forces this propeller shaped wedge in place between the two ilium, locking it in place and creating more stability due to the design of the bones themselves. The propeller shape of the wedges increases stability in multiple directions. If the sacrum was just a plane triangle wedge between two inward sloped bones there would be no forward and backward stability. The sacrum fits like a key into the keyhole of the opening between the two ilia. PICTURE OF SACRUM
4. The SI joint is NOT a smooth joint. There are numerous ridges and “irregularities” in the joint ranging from 2-11mm in height. These ridges and depressions fit together like a lock and key creating a higher coefficient of friction between the sacrum and ilium. The joint surfaces of the sacrum and ilium that make up the SI joint are like two pieces of sandpaper being pushed together. Try to slide them apart. They won’t move.
   1. THESE ARE NOT BONE SPURS!!! Men often have more of these ridges and depression in the joint. This makes sense because men are often heavier and would necessitate a rougher SI joint to create more stability.
5. Research shows that the SI joint is VERY stable. SI joint movement has been measured up to a maximum of 0.043-1.2 degrees (depending on the study) and less than 1 mm!
   1. Even when the pubic symphysis was CUT the SI joint mobility was still less that ONE MILLIMETER when a load was added to the SI joint.
6. There is no evidence that the chiropractic side posture adjustment actually repositions the sacrum or ilium.

But I hear it “pop” when my chiropractor adjusts my SI joint with a side posture adjustment

No, you don’t. What you are hearing is called a cavitation. A cavitation is a formation of gas bubbles in the liquid in the joint space. Cavitation (popping) is NOT NOT NOT an indicator of a successful adjustment. You or your chiropractor didn’t get anything to “GO” anywhere. The sounds happen when there is a distraction or mobilization of the joint that creates an air bubble in the joint. Anyone can get a joint to cavitate.

Cavitation does sometimes happen during a chiropractic adjustment but not always. It does also sometimes happen during injuries. An adjustment is accomplished by diagnosing the improper position of a bone or bones and using a quick low amplitude force to change the bone or bones position. As we see above this is not something that can really be accurately measured or changed with any significance when considering the SI joint. MRI VIDEO LINK

What you are hearing is likely the joints between the L5-S1 facet joint between the L5 vertebra and the sacrum.  Remember the L5-S1 facet joint is designed to move the SI joint is not!

But my SI joint feels better when my chiropractor adjusts my SI joint with a side posture chiropractic adjustment

It is very difficult to identify TRUE SI joint dysfunction. The gold standard to accurately diagnose pain originating from SI joint is to inject the joint with an anti-inflammatory and see if the pain reduces. If the pain reduces then you know that the SI joint was the source of the pain. However, there are a number of other lumbar and pelvic problems that can cause pain that feels like SI joint pain.

Unfortunately, the orthopedic tests being used to identify SI joint dysfunction are never accurate at determining if a patient will respond to an SI joint injection. Even if they could identify that you have SI joint dysfunction, it’s clear that the significant limitations of motion in the joint suggest that an adjustment to the SI joint, if possible, is not going to fix the problem.

First, if your chiropractor thinks the problem is likely TOO MUCH motion with true SI joint problems. This is often caused by postural distortions that improperly load the SI joints, which would lead to the SI joint not being stable. When this happens you need a structurally focused chiropractor to correct the structure of the spine and pelvis so that the SI joint is equally loaded and balanced. The traditional chiropractic side posture adjustment, if it, in fact, does what most chiropractors think it does, would make the joint more mobile, which is not what the SI joint is designed to do.

Please understand this is not an attack on chiropractic or other chiropractors. The point of this blog is to educate the public and other chiropractors about the SI joint. I am just as guilty as every other Greenville chiropractor of doing a side posture chiropractic adjustment and thinking I was doing something that I now know I wasn’t. For more information please see this YouTube video where Dr. Deed Harrison explains the SI joint in GREAT DETAIL.