Nutation
Nutation: is theanterior rotation of sacrum relative to ilium, and/or relative posterior rotation of ilium relative the to sacrum. The erector spinae and psoas are examples of muscle that may nutate the sacrum.
Nutation
Nutation is the anterior rotation of the sacrum relative to the ilium and/or the posterior rotation of the ilium relative to the sacrum. The erector spinae and psoas muscles are examples of muscles that may nutate the sacrum.