The Key Approach aims to promote a better understanding of the integrated function of the whole spine which after all, is the backbone of our being. It outlines how the spine ‘should’ function and how changed movement patterns affect joint protection mechanisms, resulting in a diverse array of common pain syndromes – both local and/or referred into a limb.

It is apparent to me that there is some confusion about sacroiliac joint (SIJ) function. On one hand some practitioners consider that the SIJ does not move – while at the other end of the spectrum, others adhere to the concept of a potentially vulnerable structure – an ‘unstable pelvis’ or one that ‘has slipped out’. Clinical evidence shows that the truth lies somewhere in between – it does move, but it doesn’t slip out. It’s more a case of directional strain that causes pain.

The sacrum or ‘sacred bone’ is a key link in the movement chain. It is both the base of the spine and part of the pelvic ring. Articulating with the two innominates on either side; L5 above and the coccyx below, it has a decoupling role between movements of the spine, pelvis and hips. It is important to appreciate that these movements are functionally interdependent – problems in one directly affect the others – how the sacrum moves directly affects movement in the pelvis, spine and hips; a problem with hip mobility will directly affect the pelvis and spine.

1) sacrum, Innominate – [(2) ilium, (3) ischium, (4) pubis], (5) pubic symphisis, (6) acetabulum, (7) obturator foramen, (8) coccyx, (red dotted line) linea terminalis.

Movements within the pelvic ring between the sacrum and the two innominates are small and subtle – yet very important in healthy control. They allow mobility of the pelvic ring – to contort or change its shape while maintaining its stability. The sacrum nods and twists between paired or contralateral movements of the innominates.

Four Fundamental Pelvic Patterns are clinically evident which allow sacral movement in the three cardinal planes. These intrinsic movements underlie both the ability for weight shift and load transfer through the pelvic girdle as well as control of postural support and the initiation of movement from the base of the spinal column.

When you examine the sacrum you will likely find it is stiff in predictable patterns which directly relate to the patients inability to perform the Fundamental Pelvic patterns 1, 3 and 4. These movements are no longer part of a patient’s habitual movement vocabulary – they have been neurologically and functionally ‘archived’. Instead, the patient over relies on the 2nd Fundamental Pelvic Pattern – which drives the problem!

The success of your intervention will rest upon restoring sacral mobility in all 3- dimensions and helping the patient relearn and regain control of the Fundamental Pelvic Patterns which are deficient.