An anastomosis of certain cerebral arteries.
A circle of branching arteries at the base of the brain formed by the basilar artery, the anterior and posterior cerebral arteries, the anterior and posterior communicating arteries and the internal carotid arteries [Described 1664. After Thomas Willis (1621-75), English physician and anatomist.]
A circle of arteries at the base of the brain, formed by the junction of the basilar, posterior cerebral, internal carotid and anterior cerebral arteries. Congenital defects may occur in these arteries and lead to the formation of aneurysms.
A ring of arteries located at the brain’s base near the rear of the skull, which, in rare instances, might have a weakness in a young, seemingly healthy adult. This weakness can lead to an abrupt hemorrhage, potentially fatal. The individual often experiences a severe headache at the back of the skull, worsening progressively until unconsciousness occurs. This condition is a type of subarachnoid hemorrhage.