[Diagnosis of infratentorial aneurysms (author's transl)].

Within a period of two years ten infratentorial aneurysms have been diagnosed. Seven have been operated on. Only rarely the diagnosis of an aneurysm of the posterior fossa can be postulated on clinical grounds or by means of computerized tomography alone. Selective catheter angiography proves to be superior to retrograde brachial angiography in five cases investigated by both methods. In those cases visualisation of an aneurysm could only be achieved by selective catheterisation. Retrospective comparison of angiographic with operative findings shows the junction of the cerebellar inferior posterior artery with the vertebral artery to be the most crucial region for diagnosis.