Anterior fontanelle closure and size in full-term children based on head computed tomography

Introduction. This study investigates radiographically acquired normative ranges of anterior fontanelle closure (AFC) and surface area (SA) in healthy full-term infants. Methods. High-resolution head computed tomography (CT) scans were retrospectively reviewed for AFC and AF dimensions to allow approximation of AF SA. Results. Between 15 and 23 head CT scans per monthly age-group (0-24 months) were reviewed, totaling 464 scans. AFC frequency increased steadily from age 10 (16%) to 20 months (88%), reaching higher than 50% at age 16 months (53%). The AF was closed in 3% to 5% of infants at 5 to 6 months. AF median SA increased from 769.3 mm2 (age 0 months) to 1022.2 mm2 (2 months), then declined steadily. Conclusions. This study provides reference charts detailing AFC frequency and AF SA as a function of age. Wide variability of AFC timing and AF size among healthy infants suggest that early or delayed AFC may represent normal variants.