Clinical and neuroradiological evaluation of 40 adult patients, suffering from migraine-type headache, produced evidence of a relationship between migraine, increased CSF pressure in the posterior fossa and cerebellar herniation. These findings have led to an alternative pathophysiological concept of migraine. A disturbance of CSF circulation is thought to be the underlying factor, which causes increased pressure in the basal cisterns and posterior fossa. This results in headache, acquired cerebellar herniation and, in severe cases, spasm of the vertebral arteries with subsequent cerebral ischemia. There seems to be no essential difference in pathophysiology between common and classic migraine.