Čes-slov Pediat 2026, 81(5):276-283 | DOI: 10.55095/CSPediatrie2026/042

Accessory fontanelles in infants: age profile of occurrence on 3D CT imaging and clinical interpretation

Dominika Laššová^{1, 2}, Michaela Dörnhöferová¹, Ľudmila Podracká²

¹ Katedra antropológie, Prírodovedecká fakulta, Univerzita Komenského, Bratislava

² Detská klinika, Lekárska fakulta, Univerzita Komenského, Národný ústav detských chorôb, Bratislava

Objective: To assess the prevalence and age-related dynamics of accessory fontanelles in children with a normal skull shape during the first two years of life, based on 3D CT head examinations performed for mild craniocerebral trauma, and to provide indicative data for the interpretation of incidentally detected accessory fontanelles in pediatric practice.

Methods: We retrospectively analysed 3D CT head scans of 348 children aged 0 - 24 months who underwent CT imaging between 2010 and 2021 at the Department of Pediatric Surgery, Comenius University Faculty of Medicine and the National Institute of Children's Diseases in Bratislava and who met the criteria for

normocephaly. Accessory fontanelles were defined as additional fibrous gaps distinct from the six constant fontanelles and, on 3D CT, were identified as sharply demarcated calvarial defects at typical locations. Age was analysed both as a continuous variable and in four categories (0 - 1, 1 - 3, 3 - 6 and 7 - 24 months). Descriptive analyses and binary logistic regression were used.

Results: At

least one accessory fontanelle was present in 9.2% of children. Among children younger than 6 months, accessory fontanelles occurred in approximately one third, whereas in those aged 7-24 months the prevalence was only 1.2%. Parietal and glabellar fontanelles showed the same overall prevalence (5.2%), while the metopic fontanelle was rare (0.6%). Increasing age significantly reduced the

likelihood of an accessory fontanelle being present (OR 0.53 per additional month).

Conclusion: Accessory fontanelles are a relatively common physiological variant in the neonatal and early infant period, with a rapid age-related decline in prevalence. An isolated accessory fontanelle in a child younger than 6 months usually does not represent a pathological finding, whereas persistence beyond 6

months is uncommon and should be evaluated in a broader clinical and imaging context.

Keywords: accessory fontanelles, infant, newborn, skull, cranial sutures, computed tomography, cranial developmental variations

Accepted: July 28, 2026; Published: July 1, 2026  Show citation