Skull scintigraphy was performed in 68 children with suspected craniosynostosis after injection of technetium-99m methylene diphosphonate. The scans demonstrated four patterns of sutural activity: normal, absent, increased, and wide. When correlated with surgical findings, "absent" indicated fused sutures, "increased" indicated fusing hyperactive sutures or sutures reacting to fusion elsewhere, and "wide" indicated splite sutures. Upon correlation with the radiographs, it was found that when the radiograph was normal, the scan contributed little; when the radiograph was abnormal or equivocal, the scan was often of great assistance in confirming fused sutures and detecting other abnormal sutures.