During cranial extension, what happens to the paired bones?

During cranial extension, what happens to the paired bones?

• A. Internally rotate
• B. Externally rotate
• C. Remain stationary
• D. Translate laterally

Answer: (A)

In cranial extension, the paired bones rotate toward each other—that is, they undergo internal rotation. This inward twist is the opposite of what happens in flexion, where the bones externally rotate and the sutures diverge. The cranial mechanism involves subtle, rhythmic movements of the skull bones; extension is characterized by this inward rotation of the paired bones, rather than remaining stationary, translating laterally, or rotating outward.

In cranial extension, the paired bones rotate toward each other—that is, they undergo internal rotation. This inward twist is the opposite of what happens in flexion, where the bones externally rotate and the sutures diverge. The cranial mechanism involves subtle, rhythmic movements of the skull bones; extension is characterized by this inward rotation of the paired bones, rather than remaining stationary, translating laterally, or rotating outward.