Say Hi to Your SI (Joint)
What is the SI Joint?
The Lowdown on Your SI Joint…
The sacroiliac joint, ever heard of it? Maybe you’ve heard the term “SI joint.” Whether you’ve heard of it or not, if you are a human with a spine and a pelvis then you have a sacroiliac joint. In fact, you have two.
The sacroiliac joints are the connections between the sacrum at the base of the spine and the ilium bones of the pelvis. If you take both of your hands and place them on the narrowest part of your waist then slide them downward until they are resting on top of the large crest of bones that wrap from back to front, you have found your ilium bones. The pelvis which connects the spine and the legs is formed by two halves, each made up of three bones–the flat and broad ilium that form the crest at the top, the pubis which is the lowest bone and connects with the opposite side and the ischium which is near the lower and posterior aspect of the pelvis and forms what we often call the “sit bones”. The three bones come together to form the socket of the hip joint.
The sacrum itself is a flat, spade shaped structure near the base of the spine. It is positioned below the lumbar spine and above the coccyx. Just as the other areas of the spine above it–the cervical spine (neck), the thoracic spine (mid back), and the lumbar spine (low back) are made up of individual vertebrae stacked on top of one another, the sacrum is composed of five individual vertebrae. Unlike the segments of the spine above it, however, the sacral vertebrae eventually fuse into a solid mass of bone beginning in the 2nd- 3rd decades of life. On occasion some people are born with six sacral vertebrae or only four. Many muscles cross from the bony sacrum to the pelvis and the femur bone of the thigh.
As noted above, where the flat sacral bone meets the ilium on either side is called the sacroiliac joint. The articulation is enclosed by a fibrous joint capsule and filled with a lubricating fluid called synovial fluid. Several ligaments span between the sacrum and the ilium further stabilizing the bony connections.
WHY IS THIS JOINT SO IMPORTANT?
Aside from acting as the only bony connection between the spine and pelvis, the SI joint’s main job is to stabilize this bony connection and to attenuate (reduce the effect of) forces traveling up the legs. While the joint is quite stable, it is capable of moving very small amounts as it absorbs the forces that travel up the legs toward the spine.
WHY DO PHYSICAL THERAPISTS WORK WITH THE SI JOINT?
Sacroiliac joint pain and dysfunction can occur for a number of reasons. Pain that is felt at the base of the spine, near the buttocks, especially on one side (though both sides can be affected) may be SI joint pain. Walking, climbing stairs, or crossing your legs may provoke this pain. Pain radiating down into the buttocks is not uncommon. Often an inciting incident can be pinpointed though not always.
Trauma such as a slip and fall, a car accident, or even repetitive trauma from sports or heavy weight lifting can cause irritation or injury to the ligaments of the joint causing inflammation and pain. Hypermobility conditions such as Ehlers Danlos Syndrome and the hormonal changes that occur in pregnancy can cause reduced tautness of the joint capsule and ligaments leading to instability and irritation. Arthritis and an inflammatory condition such as sacroiliitis can also cause SI joint pain and dysfunction.
Because low back pain and SI joint pain can be confused for one another, physical therapists often perform a series of tests and assessments to differentiate between the two. Once SI joint dysfunction has been identified, a physical therapist can prescribe a rehabilitation program to restore normal mobility to the joint, stabilize it, reduce irritation, help the client return to their regular activities, and reduce the likelihood of the pain recurring.
WHEN SHOULD I CALL A PT?
If you are experiencing pain or discomfort that sounds like it may be coming from your SI joint, the physical therapists at Evolve are ready to help. Not only can they identify the location of your pain, help you understand the condition, and begin to address your symptoms, but they will empower you with the knowledge and understanding to stay symptom free moving forward. If you are having pain, call for an evaluation today and get on the road to recovery.
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About EvolveNY-
Brooklyn's Premier Holistic Physical Therapy Clinics- There’s physical therapy, there’s training, and then there’s EVOLVE. We use the science of biomechanics merged with fitness to help our patients get better and stay better!
First we evaluate, then we heal, then we strengthen our clients so they can reach their goals, feel better, and live happier lives. We do so by utilizing a range of core techniques and specialized treatments to reduce pain, improve mobility, enhance physical strength and deal with the underlying issues, not just the pain itself.
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