Home / Sacroiliac Joint

The Sacroiliac Joint

The sacroiliac (SI) joint is located between the sacrum and ilium and connects the spine to the pelvis. The SI joint is the largest joint in the spine and allows the transfer of forces between the lumbar spine and the lower body. If the SI joint is injured or degenerates over time, it may cause chronic pain. 

Causes of SI Joint Pain

Pain may be caused by a single (traumatic) event or may develop over time (atraumatic).



Motor Vehicle Accident




Adjacent Segment Disorder

Prior Lumbar Fusion

Cumulative Injury



Inflammatory Arthropathy


Symptoms & Complaints

  • Lower back pain
  • Lower extremity pain (numbness, tingling, weakness)
  • Pelvis / buttock pain
  • Hip / groin pain
  • Single leg instability (buckling, giving away)
  • Disturbed sleep patterns
  • Disturbed sitting patterns (unable to sit on one side or for long periods)
  • Pain when going from sitting to standing

Clinical studies have reported that up to 30% of chronic low back pain may originate from the SI joint.1 SI joint pain may be similar to pain from other sources of pain in the low back. For this reason, working with a health care professional to isolate the exact source of your pain is critical to finding the right treatment.


A health care provider trained to diagnose SI joint pain will use a combination of methods to diagnose the cause of your pain. Listening to your history and complaints as well as performing a series of physical tests are the first steps in the diagnostic process. Imaging such as X-Rays, CT-scans, and/or MRIs may also be used. A diagnostic injection is used to confirm the source of your pain and may offer short-term relief.

Treatment Options

Treatment options for SI joint pain may include oral medications, physical therapy, stabilization using a pelvic belt, or injection therapy. If non-surgical treatments do not provide relief, you may be a candidate for minimally invasive SI joint fusion surgery.

Learn more about SI joint fusion with Alevio’s Implants

1. Weksler, et al. Archives of Orthopaedic and Trauma Surgery 2007; 127, No. 10: 885-888.