The purpose of the present work is to expose the defects of parietal bone ossification and to identify the criteria for differential diagnosis and brain changes related to the condition, with particular attention to the venous developmental anomalies and the pathological features associated.
Foramina parietalia permagna (FPP) are caused by an insufficient intramembranous ossification around the parietal notch that is normally obliterated in the fifth month of normal foetal development. During the first few years of life as calvarial growth continues, cranium bifidum tends to resolve into two distinct, large parietal foramina. Most people with FPP have a positive family history as the condition is inherited in an autosomal dominant fashion with high, but incomplete penetrance. Mutations of either MSX2 or ALX4 genes are associated with enlarged parietal foramina. Meningeal cortical vascular malformation of the straight sinus and persistent falcine sinus have also been reported in the literature as possible associated anomalies.