Bilateral intracranial arterial aneurysms with a persistent trigeminal artery

A 62-year-old hypertensive woman had bilateral intracranial arterial aneurysms associated with persistent trigeminal artery. The presenting symptom of this patient was painless ophthalmoplegia. We review embryologic development of the circle of Willis as an explanation for the occurence of the trigeminal artery. We also discuss the high incidence of associated vascular malformations with these vessels.