The literature on the formation of cerebral veins is reviewed to obtain a better understanding of some cerebrovascular anomalies. Clinical observations such as the entry of the superior ophthalmic vein into the cavernous sinus through the inferior rather than the superior orbital fissure, the relative infrequency of middle cerebral vein backflow in the presence of an extensive cavernous fistula, and the relative infrequency of hemorrhage in relation to the inferior petrosal fistula all relate to the persistence of an older venous pathway. The frequent occurrence of hemorrhage in association with the superior petrosal sinus fistula and the frequent failure of the superior petrosal sinus to connect to the cavernous sinus similarly have an embryological explanation. The frequent association of the vein of Galen aneurysm and an absent or deformed straight sinus probably relates to the time at which the paired internal cerebral veins fuse into one channel. It is speculated that the origins of cerebral venous malformations (CVMs) and arteriovenous malformations (AVMs) probably relate to sequential formation and absorption of surface veins, which occur in human embryonic development mainly in the 40- to 80-mm length interval, although persistent AVM growth is possible even after birth. The frequent absence or anomaly of the middle cerebral vein and its failure to communicate with the cavernous sinus in the presence of both CVMs and AVMs are linked to the late development of that vein and to its even later connection to the cavernous sinus.

We report a family with nodular subependymal masses of heterotopic gray matter occurring in six members in four generations. Only female members of the family are affected, and there is a high rate of spontaneous abortion, consistent with X-linked dominant inheritance, and lack of viability in affected males. Both in this family and in sporadic cases of subependymal heterotopias there is a high frequency of convulsive disorders, suggesting that epilepsy may be the major clinical manifestation of this developmental defect.

Three cases of cerebral venous malformation (CVM) are presented to demonstrate the triad that characterizes CVM: abnormal surface venous drainage, a "star-cluster" system of deep collecting veins, and a deep draining vein. Four other cases are introduced that illustrate this triad and show an additional feature, namely arterial fistulization; these cases represent arteriovenous malformations (AVMs). A final case demonstrates a CVM within an AVM. Both of these structures have a common draining vein and an identical venous core. On the basis of the cases described and of others less suitable for illustration, it is postulated that an AVM is a fistulized CVM and that both relate to a failure in the development of the cortical venous mantle. This proposition is based on the authors' observations and their assessment of the "best possible fit."

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Spontaneous intracerebral hematoma associated with carotid-cavernous fistula is rare. Three new cases are presented. In each, the hemorrhage originated in the vicinity of localized intracranial venous engorgement, as demonstrated by cerebral angiography. Rupture of one or several of the distended venous channels from increased back-flow is postulated as the etiology of the intraparenchymal hematomas.