The widespread use of cerebral arteriography as a diagnostic adjunct in the investigation of disorders of the central nervous system has led to an increased interest in arteriovenous malformations of the brain. There are many reported cases in the literature, and the clinical manifestations, diagnosis, and management have been discussed in detail. Most of the cases in these reports concern large anomalies. Some small malformations are included, but scant attention is given to their important clinical and pathological manifestations. In 1951 Margolis and coworkers called attention to the role of small arteriovenous malformations in the production of spontaneous intracerebral hematomas. They reviewed the literature and presented their own series. Their evidence was further corroborated more recently by the pathological investigations of Bailey, Werner, and others. In 1956, Crawford and Russell discussed the subject of small arteriovenous malformations. They analyzed and correlated the clinical and pathological findings in 20 cases. Their