reported to exist in 60% of routine skull examinations.
In 90% of cases, these openings are smaller than 1 mm in diameter by the time of skull maturation and serve as a conduit for an emissary vein.
Anomaly is caused by a failure of completion of ossification within the parietal bones. Normally, ossification begins in a single center of the parietal bones as early as the seventh week of fetal life and is normally complete by the seventh month.
Foramina parietalia permagna is inherited as an autosomal dominant trait.