Lateral sacral artery supply to an intramedullary arteriovenous fistula at the conus medullaris.

In this 25-year-old woman, severe low back pain, flaccid paraparesis, sensory disturbance of both legs and sphincter dysfunction resulted from an intramedullary conal arteriovenous malformation fed by an anterior spinal artery arising from the left sixth intercostal artery and by the left lateral sacral artery, a branch of the left internal iliac artery.