Dysfunction: Sacroiliac / SI Joints Anatomy, Pain & Issues

SI dysfunction occurs when the sacrum moves too much or too little for the joint to be able to function — or distribute force — optimally, causing pain. – Amber Burke


The primary defining symptom associated SI joint dysfunction is:

  • Low back pain on or around the PSIS, on one side of the body only.

Other symptoms (per Amber Burke) include:

  • A worsening of pain from sitting, holding positions for long periods, walking up or down stairs or hills, asymmetrical movements, during menstruation and other activities
  • In more severe cases, pain (sharp or dull) in the buttocks, groin or thighs, occurring on only one side

Finding The PSIS

The posterior superior iliac spine (PSIS)… is the rear-most point of bone on the pelvis… Palpate it by pressing your fingers into the back of the pelvis above the main mass of the buttock, about two or three inches to the side of the center line of the upper sacrum… You will feel a distinct, bony prominence beneath your fingers. If… that spot, or the depression just to the inside of it, is achy or tender… [it is] probably… the classic SI problem associated with yoga. – Roger Cole

Distinguishing From Other Issues

  • Pain is only assumed to be related to an SI joint issue if it is limited to the area of one PSIS.
  • If the pain is not limited to around one PSIS (for example, pain is instead over both PSIS or in the middle of the sacrum or in the low back, etc.), it is assumed to be due to a different cause.
  • Some other possible issues include Sciatica and Lumbago.


When the gluteus medius is weak and the groins are tight, it gets injured, and this injury can cause referred pain that extends into the lower back—often called “lumbago”—as well as pain that can be mistaken for sacroiliac joint dysfunction. – Doug Keller

SI Pain vs. Sciatica

Sciatic pain feels like it passes deep through in the fleshy part of the buttock and travels down the back of the thigh (on the outer side). SI pain emanates from above the buttock and travels only down the side of the thigh, not along the back of it. Also, if your student’s pain radiates all the way to her foot, she would feel sciatica between her first and second toes, whereas she would feel SI pain only on the outer edge of her foot or heel. – Roger Cole

Why the Pain?

How could a joint with so little wiggle room shift out of position to an extent that causes pain? “Because this area… contains a lot of nerves, even a small unevenness in the mechanics here can cause irritation to the nerves of the sacrum or lumbar spine. It is also in an important place—because of the sacrum’s location, consequences of small misalignments may reverberate through the spine and pelvis.” [Bill Reif] – Amber Burke


  • Approximately 15% of people with low back pain, or 10 million Americans (Amber Burke)


Susceptibility to SI joint problems is increased for:

  1. Women
  2. Yoga practitioners
  3. Those with looser ligaments

Women are more susceptible to sacroiliac trouble than men because:

  • The structure of the female pelvis makes the SI joint less stable.
  • Women tend to have more flexible ligaments than men.
  • Childbirth “puts enormous strain on the SI joints.”
  • In addition, David Coulter notes that athletic young women generally have more mobile SI joints than men in comparable condition.

Looser Ligaments, Advanced Poses Increase Risk

Some of us were born with looser ligaments, which enables us to do more advanced yoga poses, but also puts us at risk for SI issues because of extra sacrum mobility. – Olga Kabel