The current paper is a review of the results attained in the past and current anatomical studies, aimed at understanding the variability and function of the diploic venous system of the human skull. The diploic veins can serve as transit for infections from the scalp to the structures contained within the cranial cavity via the emissary veins, due to their interconnections with the pericranial veins, meningeal veins and dural sinuses. Thereby this clinical aspect has also been discussed.