We can think of the pelvis like a bowl and the spinal column like a broom handle sticking up from the bottom of the bowl.  This picture demonstrates how necessary the surrounding muscles, ligaments and connective tissue are for keeping both elements stable.

The position of the legs, pelvis and spine are all related as you can see.  The ability to perform movements in Yoga such as backbend or forward bend are dependant on the position of the leg and hip muscles.  For instance if the hamstrings are tight, the pelvis is forced to tuck under, which affects the ability to come forward, say in a straddle pose (wide legged forward bend).  On the other hand, a back bend will be affected by tight hip flexors forcing and anterior tilt.  The tendency then is to come backward by compressing the lumbar spine, rather from any mobility in the thoracic region.

If we persistently lol on our couch to watch TV in the same posture (leaning say, sideways to the left) this eventually has an effect on all three elements.  Side lying in bed on the same side every night is a classic example of how the hip is being hiked on the same side, perhaps for 8 hours at a time and this enevitable has an effect on the rotation of the pelvis during the day and the shortening of the waist muscles on one side.  Here is a picture to demonstrate:

Similarly, the load carried during pregnancy can have an affect on pelvic alignment post partum:

The hip joint often becomes overworked and a malalignment in the Sacro Illiac Joint occurs.  This joint is either side of the spine and often gets jammed forward on one side:

When the joint is constantly aggravated it becomes painful and inflamed and we call this sacroillitis. Often misdiagnosed as lower back pain, sacroiliitis is related to diseases that cause inflammatory arthritis in the Spine

It is the largest join of the spine and can be unstable if the person is hypermobile.  If it is tipped forward or back it is very painful and you cannot voluntarily realign the pelvis by thinking it back into position or by doing movements that readjust it.  This is known as Torqued Sacrum.  The pelvis can also be hiked upward which presents as leg length discrepancy.  Often you can go to a manual therapist (Physio, Chiropractor, Sports Masseur, Osteopath) and he or she will pop it back into position for you but it might be back out by the time you arrive home!  So it’s useful to learn some release yourself and this is done by controlling the muscles around the joint and further up and down the chain of muscle command.

The first thing to do is to relax the back musculature to take forces from the lumbar spine where it meets the pelvis.  The spine being longer at the back of the waist will allow other readjustments to take place, usually lying on the side.  You need to be able to control the muscles of your low back as well as the hip flexors at the front of the pelvis so that you can remove the compression forces on the SI joint.  In Somatics we are looking for smooth movements, like a gentle wave.  If you notice a jerkiness or a judder, this is an indication of Sensory Motor Amnesia – the Sensory Motor Cortex has literally forgotten how to let go of the tension in the muscles due to long held habits.  Doing the movement slowly will retrain the brain to let go and allow you to make the movement pattern smoother and smoother.

Life Hacks to prevent SI Joint Issues

All these involve being AWARE of your pelvis and attempting to keep it level at all times.  Even 20 minutes of side leaning on the couch or leaning on the arm rest whilst driving can cause a lateral tilt of the pelvis and malalignment of the SI joint so please be aware of adjusting your sitting, standing and sleeping positions to keep your spine and pelvis level.