In infants, what is the soft membranous spot between the skull bones called?

• A. Fontanelle
• B. Sutures
• C. Foramen
• D. Fissure

Answer: (A)

Infants have soft spots on the skull where the bones haven’t yet fused. These are called fontanelles. They’re soft and membranous because the skull bones are still separated by flexible membranes during early life, which allows room for brain growth and helps the head pass through the birth canal. Sutures are the fibrous joints between skull bones, but they’re not the soft spots themselves; they’re the boundaries that will ossify over time. Foramen and fissure are openings or slits in bone for nerves, vessels, or anatomy of the skull—not soft membranous gaps. So the soft membranous spot between the skull bones is the fontanelle. The main ones are the anterior fontanelle (between the frontal and parietal bones) and the posterior fontanelle (between the parietal and occipital bones), which gradually close as the child grows.