What characterizes cranial extension?

Cranial extension, a movement that occurs during the craniosacral rhythm, involves specific movements of the cranial bones and their relationship to the sacrum. In this context, when the cranium undergoes extension, the sacrum typically nutates. Nutation refers to the forward or anterior movement of the sacral base towards the pelvis, which occurs in response to the extension of the cranium.

This movement is part of the craniosacral system's physiological processes, which includes the movement of cerebrospinal fluid and the influence of cranial bone movement on the sacrum. The paired bones of the cranium do not internally rotate during cranial extension; instead, they participate in a more complex pattern of motion that facilitates the overall craniosacral rhythm. Similarly, the midline bones flexing is more relevant to other movements within this system.

Thus, recognizing the sacral nutation occurring during cranial extension is key to understanding the dynamics of craniosacral function and how the movements of the cranium and sacrum are interlinked.