The anterior fontanelle is the diamond-shaped opening at the top of an infant’s skull where the frontal and parietal bones have not yet fused together. This soft spot typically closes between 12 and 18 months of age. In neonatal sonography, the anterior fontanelle is the most important acoustic window for imaging the infant brain because it allows the ultrasound beam to pass through without being blocked by bone. Through this window, sonographers can evaluate the brain’s ventricles, parenchyma, and midline structures, making it possible to diagnose conditions like intraventricular hemorrhage, hydrocephalus, and periventricular leukomalacia in premature infants.
Sonography Term