Where is my SI Joint and Why Does it Hurt?

The first key to understanding SI joint pain is understanding the anatomy. SI stands for Sacro-Iliac. There are two Sacroiliac (SI) joints in your body, located on either side of the triangle-shaped bone at the bottom of your spine where it connects to your pelvis. The SI joints are a shock absorber for your spine and provide stability for your body as you run, walk, or jump. Interestingly enough, the SI joints usually don’t move more than 2 – 4 millimeters themselves. But each one contains many nerve endings that can cause significant pain if the joint is damaged or loses its ability to move properly. Everyday wear and tear, arthritis, or a single injury can damage these joints, changing their normal movement and creating chronic and sometimes debilitating SI joint pain that often, generally feels like low back pain.

SI joint pain overview

When SI Joint Pain Becomes Chronic

Chronic SI joint pain is defined as pain originating from a problem with one or both of the SI joints which has lasted for three months or longer. But the connection between low back pain and the symptoms associated with a condition called Sacroiliac (SI) Joint Dysfunction are not always obvious to the people suffering from them, or to treating physicians. When it comes to chronic low back pain, the cause is a problem with an SI joint in about 20% of cases.1 That number rises to 30% in low back pain patients with a previous lumbar fusion.2 If you’re among them, learning about SI joint pain causes, symptoms, diagnosis and treatment options can help you find the relief you need.

Symptoms of SI Joint Pain

How do you know if the pain you’re feeling is being caused by an SI joint problem? There are some common symptoms:

Low back pain: Usually a dull ache on one side of your lower back that may extend into the thigh. It is usually below the L5, or lowest lumbar vertebrae.

Buttock Pain: Pain can range from an ache to a sharp stabbing pain that extends down one or both legs.

Low Back Pain While Climbing Stairs: Activities that require the pelvis to twist may produce SI joint pain.

Difficulty Sitting or Lying on One Side: Often experienced as an ache on one side that causes you to shift weight to one side to relieve the pain in the other.

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SI joint pain symptoms

SI joint pain causes

Causes of SI Joint Dysfunction

There are a number of disorders that can affect the joints, including those that cause Sacroiliac Joint Dysfunction and its resulting pain in the SI joint. Learn more about the most common causes of SI joint pain:



SI Joint Injury

Altered Walking Pattern


Prior Lumbar Fusion


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Diagnosing SI Joint Pain

Though one of the first steps in getting to the bottom of SI joint pain is a thorough history and medical evaluation, there are other specific tests that physicians can conduct which can lead to a more definitive diagnosis of SI Joint Dysfunction. These include:

SI Joint Provocative Tests

SI Joint Injections

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Diagnosing SI joint pain

SI joint pain treatments

Treating SI Joint Pain

From non-invasive treatment options like SI joint belts and chiropractic care to surgical treatment in more serious SI joint dysfunction cases, there are now more options for treating SI joint pain than ever before. Find a physician with experience treating SI joint dysfunction to learn which of these options may be right for you:

SI Joint Belts


Physical Therapy


SI Joint Injections

Radiofrequency Ablation

SI Joint Fusion

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Ref 1. Bernard et al. Recognizing Specific Characteristics of Non-Specific Low Back Pain. Clinical Orthopedics and Related Research. April 1987; 2017: 266-280
Ref 2. Maigne, et al. Sacroiliac Joint Pain after lumbar fusion. A study with anesthetic blocks. Eur Spine J 2005; 14:654-8