A 49-year-old man developed a spontaneous vertebral artery dissection leading to cerebellar and brain stem infarction. Cerebral angiograph demonstrated redundancy, including kinks, loops and coils, in multiple cervicocephalic arteries, in addition to the dissecting artery. Histological examination of the superficial temporal artery revealed segmental disruptions of the internal elastic lamina and intimal abnormalities. These ultrastructural abnormalities may impair vessel wall integrity and predispose to nontraumatic arterial dissection and vascular tortuosity.