What Is the SI Joint?

Its full name is the sacroiliac joint. There are two of them in your lower back, and they sit on each side of your spine. Their main job is to carry the weight of your upper body when you stand or walk and shift that load to your legs.

Symptoms:

It could be a dull or sharp. It starts at your SI joint, but it can move to your buttocks, thighs, groin, or upper back.

Sometimes standing up triggers the pain, and a lot of times you feel it only on one side of your lower back. You may notice that it bothers you more in the morning and gets better during the day.

It’s more common than you might think. About 15%-30% of people who hurt like this have a problem with the SI joint.

Causes:

The pain starts when your SI joint gets inflamed. There are several reasons it could happen. You could hurt it when you play sports or if you fall down. You might also get this problem from an activity that gives the area a regular pounding, like jogging.

Do you take uneven strides when you walk because one of your legs is longer than the other? That could be a cause of SI joint pain.

Sometimes you start hurting when the ligaments that hold your SI joint together are damaged, which may make the joint move abnormally.

Arthritis can lead to the problem. A type that affects your spine, called ankylosing spondylitis, can damage the SI joint. You’ll also hurt when the cartilage over the SI joint slowly wears away as you age.

SI joint pain may also start if you’re pregnant. Your body releases hormones that cause your joints to loosen up and move more, which leads to changes in the way the joints move.

Treatments:

You have many choices for treatment. The first step is simply to stop the things that make you hurt. Your doctor will tell you to lay off any sports that inflame your joint. He may also prescribe some pain drugs.

Some other ways to feel better:

Physical therapy. Exercises can improve strength and make you more flexible. You’ll learn to correct any habits you might have picked up when you were trying to avoid pain, like walking with a limp or leaning to one side. Your therapist may try ultrasound, heat and cold treatments, massage, and stretching.

Injections. You may get a shot of cortisone to cut down the inflammation in your joint. If that doesn’t help, your doctor may numb the nerves around your SI joint to give you relief.