The presence of fontanelles on a newborn primarily facilitates which mechanical process during birth?

• A. Bones to fuse
• B. Bones to flex
• C. Bones to rotate
• D. Bones to compress

Answer: (B)

Fontanelles provide flexibility in the newborn’s skull, allowing the bones to move relative to one another so the head can mold as it passes through the birth canal. Because these gaps are not yet fused, the skull can flex and the bones can overlap slightly, accommodating the diameter of the pelvis without the bones needing to fuse. After birth, the fontanelles gradually close as the brain grows. The other options don’t capture this primary role: fusing would make passage harder, rotation is a consequence of head and pelvis dynamics rather than a direct function of fontanelles, and “compress” is not the main, defining mechanism behind molding.