1990 年 49 巻 4 号 p. 424-432
Five patients with vertigo were examined radiologically and neurotologically.
Generally a posterior inferior cerebellar artery (PI-CA) branching from the vertebral artery (VA) below the foramen magnum is seldom seen in normal persons. But if a PICA or bypass branches from the VA below the foramen magnum, vertebro-basilar insufficiency may occur due to pressure on the bloodstream from the edge of the foramen magnum, especially during tests in the hanging head position.
The diagnosis of vertebro-basilar insufficiency induced by pressure by the edge of foramen magnum was made by vertebral angiography in five cases.
Electronystagmography results also presented.