Corpus: Anterior choroidal artery

The anterior choroidal artery, or AChA for short, is a vascular branch of the internal carotid artery.

2.1. Course

The anterior choroidal artery usually arises from the cerebral artery of the internal carotid artery (C7 segment, according to Bouthillier). It originates approximately 2 to 5 mm before the bifurcation of the anterior cerebral artery and the middle cerebral artery and 2 to 5 mm after the exit of the posterior communicating artery (PCom).

The artery, which is on average 0.8 mm thick, runs adjacent to the base of the brain between the optic tract and the medial edge of the temporal lobe. It first courses lateral to the tract and then bends medially to its inferomedial surface. It then runs laterally of the tract again, around the cerebral peduncle, and reaches the lateral geniculate nucleus. In the final section of the cisternal segment, which is approx. 2.5 cm long, the AChA travels posterolaterally above the uncus parahippocampalis in order to enter the choroid fissure of the lateral ventricle. From this so-called plexus point, the artery runs intraventricularly.

2.2. Branches

The anterior choroidal artery gives off the following branches:

• Rami choroidei ventriculi lateralis: to the choroid plexus of the temporal horn of the lateral ventricle
• Rami substantiae perforatae anterioris: to the substantia perforata anterior
• Rami chiasmatici: to the optic chiasm
• Rami tractus optici: to the optic tract
• Rami corporis geniculati lateralis: to the corpus geniculatum laterale
• Rami cruris posterioris capsulae internae: to the capsula interna
• Rami globi pallidi: to the globus pallidus
• Rami caudae nuclei caudati: to the caudate nucleus
• Rami hippocampi: to the hippocampus
• Rami corporis amygdaloidei: to the amygdala
• Rami nucleorum thalami: to the thalamus
• Rami substantiae nigrae et nuclei rubri: to the substantia nigra and the red nucleus
• Rami cruris cerebri: to the crus cerebri

The anterior choroidal artery supplies many brain structures with the branches mentioned above. These include, for example:

• posterior crus and retrolenticular part of the internal capsule incl. optic radiatio
• lateral thalamus incl. lateral geniculate nucleus
• optic chiasm, optic tract
• lateral pedunculus cerebri, substantia nigra, red nucleus
• internal globus pallidus
• tail of the caudate nucleus
• mesial temporal lobe: uncus parahippocampalis, amygdala
• choroid plexus of the temporal horn of the lateral ventricles

The AChA rarely arises from the middle cerebral artery or the posterior communicating artery. In about 5 % of cases, the AChA is double. In hyperplastic AChA, the vessel can take over supply areas of the posterior cerebral artery.

A cerebral infarction in the area of the internal choroidal artery can lead to anterior choroidal artery syndrome. It is characterized by:

• hemiparesis
• hemianaesthesia
• contralateral hemianopsia

Furthermore, a left hemineglect can occur with right-sided lesions and speech disorders with left-sided lesions. Incomplete forms with lacunar syndromes and ataxic hemiparesis are more common.