Unusual presence of Wormian (sutural) bones in human skulls

Wormian bones are a subset of the small intrasutural bones that lie between the cranial sutures formed by the bones of the skull vault. They are formed due to additional ossification centres in or near sutures. They are usually considered as normal variants and seem to be determined genetically in certain populations. They have been linked with rapid cranial expansion as they appear in great number in hydrocephalic skulls. They are commonly found in the lambdoid suture and fontanelles but are occasionally seen in other sutures especially the coronal, squamosal, and sagittal sutures. We examined 25 dried human skulls with the aim to find out the occurrence and variations of Wormian bones, and surprisingly we found Wormian bones in the coronal, squamosal, and sagittal sutures in 6 skulls. These are uncommon sites of occurrence of sutural bones as reported in the literature. These findings prompted us to report these cases as their presence can lead to confusion in diagnosis in cases of skull fractures. (Folia Morphol 2011; 70, 4: 291–294