[Clinical problems in extracranial vascular processes (author's transl)].

About 20 to 30% of the cerebral circulatory disturbances caused by arteriosclerosis depend on extracranial angiostenoses and vascular occlusions. Most frequently they are found in the region of the A. carotis interna, more seldomly the A. vertebralis or the A. subclavia and the aortic arch. The blood supply of the cerebral vascular regions concerned depends on the constitution and caliber of the collateral vessels, on their wall condition and elasticity, the blood pressure in the collateral circulation and the factor of time, the localization and the extension of the arterial disease. With regard to their effect asymptomatic stenoses and occlusions are differentiated from the transitory cerebral ischemia, the manifest encephalomalacia and the defective states. The clinical symptoms in extracranial angiostenoses and vascular occlusions, the necessary additional examinations to localize the process and to establish the differential diagnosis are discussed.