The sacroiliac joint: An often overlooked cause of low back pain

At the base of your spine there is a really odd-looking bone called the sacrum. It joins with each side of your pelvis, making two sacroiliac (SI) joints. There’s not much motion at these sacroiliac joints. Beyond the sixth decade of life they probably don’t even move at all. Before that point, they move slightly with your normal activities, like walking.

Photo courtesy

Photo courtesy

There are times that one SI joint becomes more mobile while the other tends to become less mobile. This can lead to low back pain. Pain from the SI joint can also be felt at the buttock, groin and thigh. 

If the SI joint were to shift from its appropriate position, it often happens with a lifting activity, particularly if the body twists while lifting. Asymmetrical hip motion can lead to SI joint problems, especially if you often squat deeply for work or exercise. The muscles listed below may also contribute to the sides of the pelvis being twisted out of place gradually over time.

An SI joint problem is frequently seen along with some or all of the following negative muscle adaptations:

  • Decreased abdominal muscle activation or strength to provide core stability
  • Asymmetric hip flexor, hamstrings, and piriformis muscle length or muscle tension
  • Asymmetric gluteus medius, gluteus maximus muscle activation or strength
  • Asymmetric lumbar muscle tension

The amount of time since injury can be a predictor of success or failure in patients receiving treatment. The sooner a patient comes into the clinic after pain onset, the quicker they have a correction of the problem and a decrease of pain. 

Sometimes I don’t see these individuals until they have been in pain for 1-2 months and then their pain takes much longer to resolve because they have negatively adapted in the ways listed above. They are often given medicine and treated based on their symptoms, but the problem is mechanical and can’t be fixed with medication.

SI joint problems tend to respond very well to Physical Therapy intervention. The injury typically requires a combination of hands-on manual therapy and therapeutic exercises to resolve. If the patient has been hurting for less than a week then there’s a great chance of rapid success, particularly with manual therapy.

Contact me at with any questions about sacroiliac joint injury.