Neurointerventional Radiology

1

What is the basic normal vascular anatomy of the brain?

Arterial

The cerebral vasculature is supplied by 4 arterial vessels—the paired internal carotid arteries (ICA) and the vertebral arteries (VA)—and can be divided into anterior and posterior circulations. The anterior circulation consists of the bilateral internal carotid arteries, which bifurcate into the anterior cerebral arteries (ACA) and the middle cerebral arteries (MCA) ( Figure 74-1, A ). The posterior circulation consists of the bilateral vertebral arteries and the basilar artery, along with its branches, including the bilateral posterior cerebral arteries (PCA). The anterior and posterior circulations are connected by the posterior communicating arteries (PCOM), and the bilateral anterior circulations are connected by the anterior communicating artery (ACOM); these connections compose the circle of Willis ( Figure 74-1, B ).

Venous

The cerebral venous system is composed of dural venous sinuses, along with deep and superficial veins. The deep cerebral venous system consists of paired internal cerebral veins and the basal veins of Rosenthal; these merge to form the paired veins of Galen, which in turn drain into the straight sinuses ( Figure 74-2 ). The superficial veins drain into the dural venous sinuses; the veins of Trolard (superior anastomotic veins) and the veins of Labbé (inferior anastomotic veins) are major named large anastomotic cortical veins. The superior sagittal sinus, inferior sagittal sinus, and bilateral transverse sinuses merge at the torcula herophili (a.k.a., the venous sinus confluence).

2

What is the basic normal arterial anatomy of the spinal cord?

The spinal cord is supplied by the anterior spinal artery (ASA) and the paired posterior spinal arteries (PSA). The ASA arises from the intradural segments of the vertebral arteries and supplies the anterior two thirds of the spinal cord. The ASA receives additional contribution from segmental arteries' medullary feeders, which course superiorly and join the ASA, forming a classic “hairpin turn” configuration ( Figure 74-3 ). Most medullary feeders arise from the lower thoracic region, where the dominant anterior segmental medullary feeder is called the artery of Adamkiewicz. This artery typically arises from a left posterior intercostal artery, most often from the T10 level, although it may arise anywhere from intercostal, subcostal, or lumbar arteries at the T7 to L4 vertebral levels and less frequently from the right side. The paired PSA are posteriorly located and supply the posterior one third of the spinal cord. These typically arise from posterior inferior cerebellar arteries (PICA) or posterior rami of the vertebral arteries, and they receive additional contributions from medullary feeders arising from the posterior radicular arteries.