The SI Joint: Dysfunction & Pain

by Katelyn Sheehan, PT

Do you have low back pain? Is the pain mostly on one side? Do you sometimes feel it move into your hip or groin? If so, dysfunction in your SI joint may be driving your pain.

What is the SI joint?
The SI joint, or sacroiliac joint, is the joint where your low back (the sacrum (S)) meets your pelvis (the iliac (I) bone). There are SI joints on both right and left sides of your back, directly next to the dimples in your low back. If you have pain on one side around the dimple of your low back, you should check in with a physical therapist to evaluate your SI joint.

Why is the SI joint important?
The SI joint is an extremely stiff and complex joint that helps with shock absorption through the spine and pelvis. If the SI joint becomes inflamed or fails to move properly, it can cause pain to the low back, hip, and groin on the affected side. 

Both of our SI joints work together to dissipate shock, so dysfunction in one SI joint can cause dysfunction and pain in the other. Most people with SI dysfunction complain of discomfort on one side; however, the cause of dysfunction may actually originate from the other side! A thorough evaluation can help determine which side might be the real problem. 

How can the SI joint become inflamed?
The SI joint frequently becomes symptomatic if it has either too much movement or too little movement. Here are some examples: 

Too much movement

• Repetitive movements (e.g. crossing your legs when sitting, digging, lifting, pulling weeds, etc.);
• Falls (e.g. landing on the sacrum, landing on one side of your low back or pelvis, stepping off of a curb with one leg landing hard); or,
• Pregnancy-related hypermobility:  the ligaments supporting the SI joint become more relaxed with pregnancy to help prepare the body for delivery.

Too little movement

• Muscle stiffness and spasms around the joint; (including the glutes, back muscles, hip flexors, and hip rotators)
• Other structural issues (e.g.  leg length differences, scoliosis);
• Impaired movement patterns (e.g. walking with a limp, in a leg brace, or walking boot after an injury causing you to lift one hip more than the other); or,
• Poor posture for prolonged periods of time.

How can Physical Therapy help?
First, your physical therapist will examine you for any structural impairments and risk factors for SI joint dysfunction. Then, they will examine how you move and what movements may be causing your pain. After this examination the physical therapist will give you a specific treatment program designed to help either stabilize or mobilize the SI joint depending on your specific impairments, and ultimately help to relieve your pain!