The sacro-iliac joint and why it is vulnerable in yoga

Recently I taught a workshop on the sacro-iliac joint but a number of folk have told me that they were disappointed to miss it, so this month I am putting down a few thoughts about it. I must begin with a disclaimer, I am not a physiologist nor an anatomist, just a humble yoga teacher. I am presenting my understanding as simply as I can. So where is this sacro-iliac joint?

Photo credit: Wikipedia

Location: the Sacro-iliac joint is the junction between the spine and the pelvis.

Photo credit: One Health Osteopathy 

It is not meant to move much - the above picture shows the ligaments that bind the joint front and back. They form a dense webbing, intended to keep this joint very stable.

So why is it a joint? Why are the bones simply not fused together like the vertebral bodies of the scrum itself?
Please take a moment to look at this video. It is very short but it illustrates why.



Some movement is required in the joint for the normal functioning of walking and other movements of the body. This little animation is an exaggeration however. The degree of movement is actually very small, around 2 degrees. If you have as little as 4 to 6 degrees you will be experiencing pain.

So the next logical question is, how on earth do you get into the situation where you have instability in one of the sacroiliac joints.

How does a sacroiliac joint become unstable?

As with any joint it can be injured due to the immense pressure brought on it by an accident such as a severe fall or car accident. Falling onto the buttocks, perhaps when falling off a horse or motorcycle, is a common cause.

Repetitive strain is another way. When an action that is asymmetric is repetitively applied it can gradually loosen the bonds of the ligaments. The repetitive rotation of a golfer, batsman or bowler would be the kind of action that could gradually lessen the integrity of the ligaments.

Force through one leg can place a tremendous asymetric strain on the joint. This could be one major trauma as in a motor accident. But when an athlete repetitively lands on the same leg, perhaps a figure skater, ballet dancer, or hurdler, this again will lessen the integrity of the ligaments.

Women are more prone to sacro-iliac joint injury than men

Notably during pregnancy, but also during the menstrual cycle, and during lactation, a women's body has elevated levels of hormones that cause the ligaments to become prone to overstretching.

Can yoga practice contribute to sacro-iliac joint instability?

I believe so, especially if we attempt to force the body into positions its structure will not allow. Here are some examples.

Seated twists while trying to keep the pelvis anchored

House photo - Yoga Spirit Studios

Many people are taught to anchor the pelvis in a seated twist. Unfortunately this sets up precisely the conditions which can lead to over-stretching of the ligaments which bind the joint, and down the track might lead to the debilitating pain of sacro-iliac instability.

When twisting in a seated position, allow the pelvis to turn slightly in the direction of the twist and then direct the movement into the thoracic spine, not the lumbar, in order to keep both the lumbar spine and the sacro-iliac joint safe.

Forcing external rotation of the hip

This can happen in attempts to do open kneed seated postures, from simple cross legged, to lotus pose. But even being over zealous in padagusthasana could create a problem.

It has to do with the shape of your hip socket in relation to the shape of the top of your thigh bone. There is a tremendous variation in the way we are built and no two hip joints are really the same. This picture illustrates that.

If your head of your femur (thigh bone) runs into the rim of your acetabulum (hips socket) in external rotation (turning the leg so the toes point outwards) and abduction (leg going out to side) and you try and force this, it is like using your thigh bone as a tyre lever to prise open the sacroiliac joint.

So how do you know if you run into such a bony constraint? You will feel a jamming sensation on the leading edge, that is, in the hip in the direction of the movement.

It is not a case of needing to become more flexible. No amount of flexibility is going to change the shape of your hip socket. In such a situation the yoga lesson is contentment, Santosha, with what you have, Satya, honouring the truth of your body, and Ahimsa, doing no harm to your body. Take the sitting posture that is right and comfortable for you.

What to do if you have sacroiliac pain?

Cease all the postures that aggravate it. This will include:

• Forward bends
• Asymetric poses, such as warrior poses
• Anything that twists, including triangle pose, reverse triangle and so on, which are also asymetric, so double reason there.

The job now is to begin to train the surrounding muscles to take up the work of the overstretched ligaments in order to provide stability in the pelvic region. Now that is your core muscles, and I include in the core group the following, some of which are often not counted as core:

• transverse abdominus
• miltifidus
• spinae erectus
• iliopsoas
• pelvic floor
• quadratus lumborum
• internal and external obliques

Here are some pictures to help you identify those.

There are many ways for you to proceed with this core training, and many lovely yoga practices to help as well. Just do 70% of what you think you can do in any one session, and only begin to reintroduce the full range of postures when you are pain free. And when you do, practice with a new awareness of pelvic stability.

Your well trained yoga teacher can help you to identify practices that will help you and which ones to avoid.

Finally, listen to your body. It is immensely wise.