Nutation occurs when the sacrum absorbs shock; it moves down, forward, and rotates to the opposite side. In rebound (counternutation) the sacrum moves up, backward, and rotates to the same side that absorbs the force. At the same time, the ilium rotates in the opposite direction.

What does nutation of the sacrum mean?

Nutation describes when the sacrum is rotated forwards relative to the iliac bones and Counternutation describes when the sacrum is rotated backwards relative to the iliac bones.

Does anterior pelvic tilt cause sacral Nutation?

Nutation is defined as a relative anterior tilt of the sacral base (upper flat surface of the sacrum that articulates with L5) in relation to the ilium (Figure 1). It is described as a relative movement because it can occur with the sacrum rotating anteriorly, the ilium rotating posteriorly, (or both).