fontanelle A soft place in the scalp over a gap between four bones of the skull (the frontal and parietal bones on each side) which is normally present in the newborn infant. It gradually closes during the first 12–18 months of life, as bone formation extends until the edges come together at the sutures. The fontanelle reveals changes in pressure inside the skull: it tends to bulge when the baby cries, and to become sunken in a state of dehydration. The pulsations of the underlying brain with the heart beat can be felt at this site through the scalp.

Stuart Judge

fontanelle (anat.) †hollow between muscles XVI; outlet for a discharge XVII; membranous space in the skull of an infant XVIII. — F. — modL. fontanella, latinization of OF. fontenelle. dim. of fotaine FOUNTAIN; see -EL2.

fontanelle (fon-tă-nel) n. an opening in the skull of a fetus or young infant due to incomplete ossification of the cranial bones and the resulting incomplete closure of the sutures. anterior f. the opening at the junction of the coronal, frontal, and sagittal sutures. posterior f. the opening at the junction of the sagittal and lambdoidal sutures.

fontanelle A gap in the bones of the skull. Newborn babies are born with a fontanelle, which disappears as the bones in the skull fuse; the fusion is complete at around 18 months of age.