[Pathogenic significance of the elongated basilaris artery].

The following phenomena are discussed as pathogenetic sequelae of an elongated and deformed A. basilaris: 1. Mechanical cerebral nerve disorders and complex infratentorial vascular syndromes. 2. Impressions of the bottom of the third ventricle by the terminal basilar or stenosing of the aquaeduct by its backward angulation. 3. Induction of an active hydrocephalus. 4. Displacement of the elongated basilar by an anterior herniation in the tentorial slot. 5. Complex conditions of a hydrocephalus development from an elevation of the a. basilaris, disorders of the dynamics of the spinal fluid and a relative stenosis of the aquaeductus. The term megadolichobasilar is reserved for the arteriosclerotically elongated and deformed basilar. One should speak of a basilar deformation in case of a distinct elevation of the terminal basilar artery in relation to the dorsum sellae level without a vascular deformation.