Two cases of dural arteriovenous fistulae of the foramen magnum with perimedullary venous drainage are reported. Their arterial component was a dural branch of a vertebral artery. The localization and the origin of these fistulae appeared very uncommon but could be explained by the embryogenesis of the vertebral arteries, of which the third portion corresponds to the first cervical radicular artery. The first patient had signs and symptoms usually described in this disease, but the second presented a subarachnoid haemorrhage with neither motor and sensory deficit not sphincter disturbance. Myelographic findings, M.R.I. abnormalities and treatment of these rare dural arteriovenous malformations are discussed.