At the base of the spine is the sacrum – a large triangular bone that is also jointed with the left and right pelvic bones at the large sacroiliac joints. The sacrum then supports the spine and the pelvic bones support the sacrum – the sacrum is the link between the spine and pelvis. The shape of the sacrum and the way in which it articulates with the pelvic bones means that in the neutral position it is angled forwards. The upper surface also slopes forwards contributing to the lumbar curve.
There is very little movement at the sacroiliac joints and any alteration in the position of the pelvic bones will result in a change in the angle of the sacrum and the shape of the lumbar curve. The pelvis is sometimes referred to as the pelvic bowl, and imagining this bowl as filled with water can help to get our heads around the next bit. If the pelvis is rotated anteriorly (tilted forwards) spilling water over the front edge, the angle of the sacrum and the lumbar lordosis increases; conversely when the pelvis is rotated posteriorly (tilted backwards) spilling water over the back edge, the sacrum becomes more vertically and the lumbar lordosis flattens out. Pelvic tilting (rocking) in this way is the same movement we performed when practicing cat and dog tilt in four‐point kneeling.
How the Butterfly Works
Sitting cross legged on the Butterfly seat with its gently sloping angle will cue the pelvis into a correct postural alignment. From there there are many different ways to use your Buttafly seat to help promote good posture, allow relaxation and promote good pelvic health.