Pain in the sacroiliac joint or SI joint (SIJ) commonly manifests as back pain. In fact, medical literature reveals that, on average, the SI joint is the source of 25 percent of low back pain. Leg pain is also commonly attributed to problems with this joint. Other characteristic indicators of SI joint problems include:
- An ache on one side of the hip area when sitting or lying down
- Buttock pain and increased back pain while climbing stairs
Women may be more prone to SI joint problems due to their anatomy:
- Greater lumbar spine curvature
- More elastic collagen (which increases the flexibility of their ligaments)
- Shorter limbs
- Wider pelvis
Pregnancy, which stretches the pelvis, can also affect the sacroiliac ligaments, causing instability. The instability may lead to SI joint problems.
SI Joint Anatomy
The SI joint is where the sacrum and pelvis come together. The joint is located at the base of the spine, above the tailbone (coccyx) but below the lumbar spine. There are two SI joints, which sit on each side of the spine. The basic function of the joint is to support the weight of the upper body. It also absorbs shock and cushions the spine from impact forces, like walking or running. In addition, the SI joint provides stability for the pelvis.
Causes of SI Joint Pain
The main cause of SI joint pain is inflammation. This can arise from:
- Altered joint motion—either too much movement (hypermobility/instability) or too little movement (hypomobility/stiffness)
- Disruption due to asymmetry in legs or uneven movement
- Falls or regular pounding, such as running
- General wear and tear
Diagnosis of SI joint disorders can be difficult. Sometimes, a physician encounters multiple problems in this area of the body, such as disc or hip problems. To accurately diagnose, the doctor conducts a physical exam and focuses on the area of pain, checking for tenderness or pain on movement. He/she considers the location of the pain and analyzes problems standing or sleeping.
Imaging tests may also be useful. These tests include:
- CT scans
- MRI scans
However, the most widely used diagnostic tool is an SI joint injection with anesthetic. If this injection substantially relieves back-related pain, the indication is that the joint is the source of the problem. If it does not, then the joint is an unlikely source of that pain.
At the Center for Pain Management, we are experienced in the treatment of sacroiliac pain. We provide the injections that are widely used for pain management of the SI joint. We also consider other non-invasive means, such as medication and/or physical therapy.