anterior choroidal artery
The anterior choroidal artery (AChA) supplies several crucial anatomical structures of the brain important for vision and motor control. Identification of AChA is important because of its strategic and extensive area of supply as well as large variations in the territorial distribution.
The AChA originates from the posterior wall of the internal carotid artery (ICA) between the origin of the posterior communicating artery (PCOM) (which is 2-5 mm proximal to the AChA) and the internal carotid termination (which is 2-5 mm distal to the AChA). It measures ~1 mm in diameter.
The AChA is located lateral to the optic tract, it then curves medially to its inferomedial surface, to curve again laterally to run along the lateral aspect of the optic tract and circumvents the cerebral peduncles to reach the lateral geniculate body. It traverses in the posterolateral direction above the uncus to enter the choroidal fissure, at the so-called plexal point.
The plexal point is an angiographic landmark for where the artery becomes intraventricular, appearing at the center of a checkmark-like course on lateral projection where the vessel descends and then sharply ascends posteriorly.
The AChA can be divided into two segments:
- cisternal segment: extends from its origin until the choroidal fissure; measures ~2.5 cm (range 1.5-3.5 cm) in length
- intraventricular segment: after entering the choroidal fissure
- cisternal segment
- deep brain structures
- mesial temporal structures (uncus)
- intraventricular segment
- choroid plexus of the anterior part of the temporal horns of the lateral ventricles
Anteriorly, there is some overlap/interindividual variation with the territories of the lenticulostriate arteries.
- occasionally it may originate from
- duplication of AChA is reported in ~5% of cases
- hyperplastic AChA in which AChA supplies the area usually associated with PCA