Wormian bones - expanded differential diagnosis and implications for abnormal head shape in infancy

Sep 29, 2026

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Wormian bones are accessory ossicles forming within cranial sutures; although often benign, high counts can signal underlying genetic or developmental disorders. This retrospective study evaluated prevalence, anatomical distribution, and clinical associations of Wormian bones in pediatric patients undergoing cranial CT imaging at a tertiary children’s hospital. Among 13,519 scans, 77 patients (0.57%) had radiologically confirmed Wormian bones, increasing to 2.1% in a 5-year clinic cohort, with lambdoid sutures as the most common site.

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Child's Nervous System (2026) 42:3 [https://doi.org/10.1007/s00381-025-06978-z](https://doi.org/10.1007/s00381-025-06978-z) Wormian bones: expanded differential diagnosis and implications for abnormal head shape in infancy Noah E. Alter1 · James L. Rogers2 · Marcelina Puc3 · Anthony Hoang4 · Izabela Galdyn1,5 · Christopher M. Bonfield6 · Matthew Pontell1,5 · Michael Golinko1,5 Received: 4 August 2025 / Accepted: 1 October 2025 © The Author(s) 2026 Abstract Purpose Wormian bones (WB) are accessory ossicles that develop within cranial sutures. While typically benign, their presence in large numbers has been associated with various genetic and developmental disorders. This study aims to characterize the prevalence, anatomical distribution, and clinical associations of WB in a pediatric population undergoing cranial CT imaging. Methods A retrospective review was conducted at Monroe Carell Jr. Children’s Hospital at Vanderbilt. Pediatric patients aged 0 to 18 years who underwent cranial CT imaging for any clinical indication were included. WB were radiologically confirmed, and demographic data, cephalic index, and comorbidities were collected and analyzed. Results Among the 13,519 patients who underwent cranial CT imaging, 77 (0.57%) had radiologically confirmed WB, totaling 476 ossicles. The prevalence increased to 2.1% when examining our clinic cohort over a 5-year period. The lambdoid suture was the most common site (343/476, 72.1%), followed by the posterior fontanelle (53/476, 11.1%) . Multiple WB (≥ 2) represented the most common phenotype (52/77, 67.5% of cases), and 13 patients (16.8%) had at least one associated skeletal or craniofacial condition, most commonly craniosynostosis (10/13, 76.9%) . Cephalic index analysis demonstrated a predominance of brachycephaly (54/77, 70.1%) . Conclusion This study presents a comprehensive evaluation of WB in a large pediatric cohort. WB may co-exist with craniosynostosis or other skeletal conditions such as osteogenesis imperfecta. Given the greater prevalence of WB compared to craniosynostosis (2.1%: clinic cohort & 0.57%: institutional cohort vs. 0.05%), clinicians should consider WB in the differential diagnosis of abnormal head shape in infancy, particularly in a subspecialist practice. Keywords Wormian bones · Cranial morphology · Abnormal Head Shape · Brachycephaly · Craniosynostosis * Michael Golinko [Michael.golinko@vumc.org](Michael.golinko@vumc.org) 1 Department of Plastic Surgery, Vanderbilt University Medical Center, Nashville, TN, USA 2 Vanderbilt University School of Medicine, Nashville, TN, USA 3 Thomas F. Frist, Jr. College of Medicine at Belmont University, Nashville, TN, USA 4 Vanderbilt University, Nashville, TN, USA 5 Division of Pediatric Plastic Surgery, Monroe Carell Jr. Children’s Hospital, Nashville, TN, USA 6 Department of Neurosurgery, Vanderbilt University Medical Center, Nashville, TN, USA Introduction Wormian bones (WB) or intrasutural bones are accessory ossicles that develop within the cranial sutures, most commonly along the lambdoid suture [1] . These bones are considered benign anatomical variants and are not associated with neurocognitive impairment [2] . While often incidentally discovered, WB, particularly in large numbers, have been associated with various genetic and developmental disorders including craniosynostosis, osteogenesis imperfecta, and cleidocranial dysplasia [1–3]. Their frequency and anatomical distribution vary widely across populations, suggesting a combined genetic and environmental influence on their development [4, 5]. Additionally, WB have been noted to influence cranial morphology, raising important diagnostic considerations when evaluating infants with atypical head shape [6] . As such, defining their baseline incidence and anatomical distribution is necessary for distinguishing benign anatomical variants from underlying pathology. Despite these recognized associations, the epidemiology

FAQs

What are Wormian bones and what makes them clinically relevant in infancy?

Wormian bones are accessory ossicles that develop within cranial sutures. While typically benign, their presence in larger numbers has been linked to genetic and developmental conditions and can affect assessment of abnormal head shape.

How prevalent are Wormian bones in the study’s pediatric CT population?

Among 13,519 patients who underwent cranial CT, 77 patients (0.57%) had radiologically confirmed Wormian bones, totaling 476 ossicles. Prevalence increased to 2.1% when examining the clinic cohort over a 5-year period.

Where are Wormian bones most commonly located, and what phenotypes were most frequent?

The lambdoid suture was the most common site (343/476, 72.1%), followed by the posterior fontanelle (53/476, 11.1%). Multiple Wormian bones (≥2) were the most common phenotype, occurring in 52/77 cases (67.5%).

What should clinicians consider when evaluating abnormal head shape in infants?

Because Wormian bones may coexist with craniosynostosis or other skeletal conditions, clinicians should include Wormian bones in the differential diagnosis of abnormal head shape in infancy, particularly in subspecialist practice.

Sep 29, 2026

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