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Sacroiliac Joint Pain - What You Need to Know

Pain at the SI Joint


Updated June 27, 2014

Written or reviewed by a board-certified physician. See About.com's Medical Review Board.

middle age woman's pain
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Sacroiliac joint pain, also referred to as SI joint pain or SI joint dysfunction, is among the common causes of low back pain. Typically, sacroiliac joint pain is very annoying and intrusive but it can most often be treated without drastic measures.

Location of Sacroiliac Joint

The sacrum, a triangle-shaped bone, sits just beneath the lumbar spine. The body's two sacroliliac joints are formed between the sacrum and the pelvic (iliac) bones to either side. The sacroiliac joint is one of the large joints in the body and characteristically there is little motion involved with the sacroiliac joint. The sacroliliac joint functions as a shock absorber, decreasing stress on the pelvis and spine.

Causes of Sacroiliac Joint Pain

Though sometimes the cause of sacroiliac joint pain remains unknown, there are a few known causes. For example, pregnancy may cause temporary sacroiliac joint pain. Also, uneven leg length that disrupts walking patterns, or injury may cause sacroiliac joint pain.

Since the sacroiliac joint is a synovial joint, it can be affected by arthritic conditions that result in cartilage damage or joint inflammation (e.g., ankylosing spondylitis).

Diagnosis of Sacroiliac Joint Pain

Your doctor will consider your complete medical history, results from your physical examination, and x-rays to determine the extent of joint damage and formulate a diagnosis. Your doctor may also find it valuable to obtain images from MRI, CT scan, and bone scan.

Symptoms of Sacroiliac Joint Pain

The primary symptom of sacroiliac joint pain, as its name suggests, is pain. The pain is usually in the lower back or back of the hip area. It can also be painful in the groin and thigh area. Pain is usually worse when standing and relieved by lying down.

In addition, when the sacroiliac joint is inflamed, there is usually stiffness that is worse in the morning and improves with activity.

Treatment of Sacroiliac Joint Pain

The treatment regimen for sacroiliac joint pain includes:

It may be a combination of conservative treatments that work best for sacroiliac joint pain. Discuss all of your options with your doctor. Don't assume that nothing can be done to offer some relief.


Sacroiliac Joint Dysfunction. eOrthopod. 8/2/2005.

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