Morphology of the Dural Venous Complex of Skull Base in Human Ontogenesis

The development of the dural venous complex of the skull base formed by the cavernous, intercavernous, and petrous dural sinuses and their connections with the intra- and extracranial veins and venous plexuses, was investigated on 112 premature stillborn human fetuses from 16 to 36 weeks of gestation by methods of vascular corrosion casting. It was established that the main intracranial dural canals approach similar to the mature arrangement at the very beginning of the early fetal period. In fetuses 16 weeks of gestation, the parasellar dural venous complex appeared as a plexiform venous ring draining the venous plexus of the orbits into the petrous sinuses. The average diameter of dural canals progressively enlarged and reached its maximum value 2.2 ± 0.53 mm approaching the 24 th week of gestation. This developmental stage is characterized by the intensive formation of the emissary veins connecting the cavernous sinus with the extracranial venous plexuses. Due to the particular fusion of the intraluminal canals, the average diameter of the lumen gradually declined to reach 1.9 ± 0.54 mm in 36-week-old fetuses. By the end of the fetal development, 21.3% of fetuses featured a considerable reduction of the primary venous system with the formation of the one-canal shaped dural venous sinuses, obliteration of several tributaries, and decreased density of the extracranial venous plexuses. In the other third of fetuses, the enhanced venous basal complex with the multi-canal shape of dural sinuses, and abundance of tributaries and anastomoses persisted thought the whole antenatal period. Thus, the genetically determined pace of reduction of the primary venous plexuses determines the final shape of the dural venous system and its compensatory abilities.