CLINICAL ARTICLE J Neurosurg Pediatr 22:323–329, 2018 T he size of the anterior fontanel is assessed by mea- suring head circumference and is generally accepted to be an index of cranial development and osseous maturation. 3,13 The anterior fontanel at birth varies in size, usually ranging from 1 to 3 cm. The age at which anterior fontanel closure occurs ranges between 10 and 24 months. The anterior fontanel size and closure time are considered to be useful clinical signs for the early diagnosis of dis- eases. For instance, a large fontanel and/or delayed closure can indicate hypothyroidism and skeletal disorders such as rickets, cleidocranial dysostosis, and increased cranial pressure. 3,13 In contrast, a small fontanel and early closure can indicate hyperthyroidism, disorders that affect brain growth such as microcephaly and craniosynostosis, and other conditions. 3,13 Thus, knowing age-related normal variations is important to decide on further investigations. In 2007, the World Health Organization (WHO) re- leased growth charts that suggested that unconstrained growth of economically advantaged, breastfed infants and children does not substantially vary and that a single set of growth curves can describe a human physiological norm up to 5 years of age. 29 However, the meta-analysis by Na- tale and Rajagopalan showed that the head size in breast- fed children examined at any age was far closer to local norms than to the Multicentre Growth Reference Study mean head size. 18 Furthermore, considerable differences in head circumference exist between WHO charts and na- tional or ethnic groups, which could put many children at risk for misdiagnosis of macrocephaly or microcephaly. 18 Racial and ethnic differences in fontanel size have also been identifed, and local references should be used for evaluating the fontanel size of infants from different ABBREVIATIONS WHO = World Health Organization. SUBMITTED November 29, 2017. ACCEPTED March 14, 2018. INCLUDE WHEN CITING Published online June 1, 2018; DOI: 10.3171/2018.3.PEDS17675. Evaluation of fontanel size variation and closure time in children followed up from birth to 24 months Perran Boran, MD, PhD, 1 Fatma Oğuz, MD, 2 Andrzej Furman, PhD, 3 and Sibel Sakarya, MD, MSc 4 1 Department of Pediatrics, Marmara University, School of Medicine; 2 Institute of Child Health, Istanbul University; 3 Institute of Environmental Sciences, Bogazici University; and 4 Department of Public Health, Marmara University, School of Medicine, Istanbul, Turkey OBJECTIVE Anterior fontanel size and closure time can be useful clinical signs for the early diagnosis of diseases. Knowing age-related normal variations is important to decide on further investigations. The authors of this study aimed to describe fontanel size variation according to age, determine fontanel closure time, and identify the optimal method for assessing fontanel size. METHODS For this prospective cohort study, 321 healthy term babies who fulflled the inclusion criteria were consecu- tively recruited. Percentile charts for the mean anterior fontanel size and oblique measurements from birth to 24 months of age were created. RESULTS The mean fontanel closure time was 9.7 ± 5.0 months (girls 10.3 ± 4.7 months, boys 9.2 ± 5.1 months). No differences were observed between the traditional method and oblique measurements. Early fontanel closure was not associated with microcephaly. CONCLUSIONS Oblique measurements can be used because they are as accurate as the traditional method. Children with fontanels measuring above the 95th percentile should be monitored closely and investigated further for potentially associated diseases. https://thejns.org/doi/abs/10.3171/2018.3.PEDS17675 KEYWORDS anterior fontanel; anthropometry; child; infant; physical examination; diagnostic technique J Neurosurg Pediatr Volume 22 • September 2018 323 ©AANS 2018, except where prohibited by US copyright law Unauthenticated | Downloaded 02/16/23 02:39 PM UTC