SI dysfunction

Mar 1, 2022

The Sacroiliac (SI) Joint is where the Sacrum and the iliac bones join in the Pelvis. The SI joint are a very common cause of low back pain and/or leg pain, and may account for up to half of all LBP causes. The SI joints are weight bearing joints supporting the spine and are prone to stress and inflammation, causing localised pain and discomfort in the lower back and/or Buttock. Sometimes even referring down into the leg and groin.



While it is not clear how the pain is caused, it is thought that an alteration in the normal joint motion may be the culprit that causes sacroiliac pain. This source of pain can be caused by either:

  • Too much movement (hypermobility or instability): The pain is typically felt in the lower back and/or hip and may radiate into groin area.
  • Too little movement (hypomobility or fixation): The pain is typically felt on one side of the low back or buttocks, and can radiate down the leg. The pain usually remains above the knee, but at times pain can extend to the ankle or foot. The pain is similar to sciatica.


Signs & Symptoms

  • Mild to Severe low back pain
  • Pain in the Buttocks
  • Pain that seems to develop in the pelvis
  • Pain in the hip
  • Pain that radiates down the leg of the affected side
  • In SI Sprain, pain may be sharp and stabbing
  • Stiffness of the lower back
  • Certain activities may increase the pain; Walking, twisting or bending
  • Leg length inequality. The length of one leg may be different that the other (shorter or longer) because either or both a functional (muscle/posture) or structural (bone/ cartilage) abnormality.

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