Have you heard of the SI joint? It’s a tricky one.
What is the SI joint?
SI stands for Sacro-iliac. Sacro = sacrum, the big wide bone at the base of the spine comprised of 5 fused vertebrae. Iliac = ilium, aka the pelvic bone, aka “the hip bone”, aka os coxae. You have two os coxae, a right and a left. The os coxae bone actually starts as 3 bones that become fused in adulthood. The ilium, the pubis and the ischium. The intersection of all 3 make up the “hip socket”, the acetabulum where the head of the femur articulates.
The articulation between the sacrum and the ilium make up the SI joint! This joint is a large joint that is planar in nature, meaning the two surfaces slide against one another to create motion. However, it’s not that simple. The SI joint is multi-planar, and simultaneously rotates and translates along three axes of motion! The degree of movement of the SI joint in those plans is very small.
All together the two os coxae and the sacrum create a continuous ring known as the pelvic basin. This along with the low back is our foundation of stability!
What does SI joint pain typically feel like?
For starters, just because you are pointing to your SI joint to identify where you are feeling pain, does not mean that is the structure that is causing the pain!
SI joint pain is typically described as dull, achy stiffness. This does not mean that if you describe your pain differently, that you do not have SI joint pain or dysfunction. Patients usually point to the area around the dimples you might see at the base of the spine. Pain can refer elsewhere in the lower back, pelvis and hip as well. Typically not associated with tingling, numbness, or sharp shooting pain traveling down into the legs or feet (although there is always potential for multiple diagnoses present simultaneously).
SI joint pain can be caused by misalignment, abnormal gait, muscle imbalances, traumatic events such as a fall or car accident, pregnancy related, being overweight, lower crossed syndrome and anatomical difference in leg lengths. SI joints often are not the main culprit, but are affected by compensation caused by another problem area such as a disc issue in the low back.
Muscular imbalances or dysfunction can present like SI joint pain as well. Referral patterns trigger points within dysfunctional muscles can be very painful and can be felt at areas away from the actual sit of the problem.
It is critical to assess muscular imbalances around the SI joint.
There are OVER 30 muscles that attach to the bones that make up the SI joint!
TFL (Tensor fasciae latae)
Rectus Femoris (vastus medius, vastus lateralis)
Biceps femoris (short head) Hamstrings
Biceps femoris (long head) Hamstrings
ITB ( Iliotibial band)
The abdominal muscles:
External abdominal obliques
Internal abdominal obliques
Low back muscles:
and the pelvic floor muscles contained within the pelvic basin!
WOW, that's a lot of muscles!
Sacro-iliac joint pain referral pattern is depicted in the image below.
-How might you assess an SI joint?
Clinical evaluation of SI joints can include palpation, range of motion, and orthopedic exams. Studies have not shown great reliability between practitioners for assessment of these joints. Therefore treatment approaches can also vary greatly from provider to provider.
We believe it is critically important to address not only the SI joints and lumbar spine, but the muscles supporting the joint as well.
Adjusting the joints feels good, of course. However, if there is muscular imbalance the effects of the adjustment will be short lived. Instead evaluating which muscles are weak, lengthened, or tight and short, and working to regain balance and normal function supports proper alignment of the joint. Muscles were designed to support and move the joint. We also believe it is important to consider if any ligament damage or laxity is present.
Here's a few go-to's to check the function of the SI joints:
As mentioned before, identifying pain coming directly from the SI joint is challenging. Evidenced by the long list of orthopedic tests above. Due to the complicated nature, an approach was developed to increase effectiveness and reliability when diagnosing SI joint dysfunction and pain. The approach is called Laslett's criteria and you can learn more about it by following the link below!
Depending on the individual treatment may include:
Adjusting- Chiropractic manipulative therapy- diversified, Thompson drop table technique
Muscle work, manual, instrument assisted, trigger point therapy
Modalities- Ultrasound, Cold laser
Rehabilitation- stretching, strengthening
Heat or Ice depending upon phase of healing
This information is not all inclusive! If you are suffering from what you think might be SI joint pain or low back pain, call the office and schedule a visit. We can determine the root of your problem and give you an idea of what treatment would look like, and whether it would be beneficial for you!
Dr. Allison Fleming and