The case is reported of a 16-year-old girl with an anterior thoracic spinal cord arteriovenous malformation (AVM) who presented with subarachnoid hemorrhage and sudden change in lower-extremity strength. Spinal angiography revealed a Type II (glomus) intramedullary AVM at the T7-8 level fed by multiple branches of the anterior spinal artery. The AVM was successfully resected using an anterolateral transthoracic approach. The details of this approach and its use for surgery of anterior thoracic spine lesions are described.