Final answer:
During craniosacral flexion, there is a reduction in the AP diameter as part of the craniosacral rhythm.
Step-by-step explanation:
When discussing craniosacral flexion, it's important to address changes in the anteroposterior (AP) diameter of the cranium. During craniosacral flexion, there is a reduction in the AP diameter as the base of the skull moves posteriorly and the frontal bone moves anteriorly. This motion is part of the craniosacral rhythm and is thought to have an influence on the flow of cerebrospinal fluid, and thus overall health in craniosacral therapy. Compression fractures, as seen in osteoporosis, can amplify this curvature due to bone loss and lead to a decrease in overall spine health.