An unusually-wide human bregmatic Wormian bone: anatomy, tomographic description, and possible significance

Abstract

Supernumerary ossicles (or Wormian bones) of the cranial vault are formations associated with insufficient rate of suture closure, and regarded as "epigenetic" and "hypostotic" traits. These bones rest along sutures and/or fill fontanelles of the neonatal skull. In this autoptic report of a 66-year-old Caucasian woman, a peculiar supernumerary bone is described, unusual size and shape, filling completely the bregmatic fontanelle. The skull was CT-scanned through coronal sections at 80 kV and 60 mA, with a slice thickness of 1.0 mm and a resolution of 0.35 mm/pixel. Segmentation and 3D rendering were computed using MIMICS 7.0 (digital endocast). The bone was pentagonal and remarkably large, more on the exocranial surface than on the endocranial one, involving both tables and diploe of the vault. This feature might represent a wedge to completion of the vault architecture. Considering the functional and structural matrix of cranial morphogenesis, this case displays the possibility of discrete diversification of the ossification centres, as well as the relative stability of the structural skull matrix in response to discrete changes.

Study of Metopism and Wormian Bones in Dry Skulls of Human Cadavers in Nepal

“…the insufficient rate of closure of the suture and it is regarded as the "epigenetic " and hypstatic" traits [13]. It was suggested that the wormian bones are not under the direct control of gene, but instead represent secondary sutural characteristics which are brought about by the stress [14].…”

“…The alternative names of wormian bones include Schaltknochen, intercalary, sutural and intrasutural bones [6]. The formations of wormian bones are associated with the alterations in the normal development of the flat bones of the skull, insufficient rate of suture closure and regarded as the "epigenetic" and "hypostatic" traits [7].…”

Incidence of Wormian Bones in Dry Human Skulls in South Indian Population

“…It can be concluded that there is disagreement among the researchers regarding the extent of morphology of the wormian bones can be attributed to environmental or genetic influences [17,18].…”

A Wormian Bone, Mimicking an Entry Gunshot Wound of the Skull, in an Anthropological Specimen

“…The mechanism of WB origin is not fully ascertained, although genetic and environmental factors have been claimed as etiological factors (2). WB arise along the cranial sutures and/or fontanels during the neonatal period in normal or pathologic conditions, with clinical significance to the diagnostic process of many genetic disorders, such as craniosynostosis (1,3).…”