The anterior choroidal arteries are small, but vital blood vessels that branch from the internal carotid arteries. They arise just proximal to the splitting of the internal carotid into the anterior and middle cerebral arteries.
The anterior choroidal arteries feed vital brain structures with blood. These structures include the posterior limbs of the internal capsules, portions of the thalami (specifically the lateral geniculate nuclei and ventral posterolateral nuclei), optic tracts, middle third of the cerebral peduncles, portions of the temporal lobes (ie: parts of the pyriform cortex, uncus, and amygdala), substantia nigra, portions of the globus pallidus, as well as the choroid plexus in the lateral ventricles.
Towards the end of its course the anterior choroidal artery forms connections with the posterior lateral choroidal arteries. Cerebral angiograms are currently the best way to visualize the anterior choroidal arteries, although given how small the vessel is, it may not always be visualized.
The anterior choroidal arteries serve some pricey brain real estate! Like many other blood vessels, the anterior choroidal artery is subject to blockage, as well as aneurysm formation.
Blockage of the anterior choroidal artery can cause a stroke. The most common symptoms of an anterior choroidal stroke are hemiparesis (weakness on the opposite side of the body including difficulty talking secondary to facial weakness), hemianesthesia (decreased sensation on the opposite side of the body), and a homonymous hemianopsia (loss of a portion of the visual field of both eyes). High blood pressure is the most common underlying factor in people with anterior choroidal artery strokes.The hemiparesis is a result of damage to the posterior limb and genu of the internal capsule. The posterior limb contains the corticospinal tracts, which send information about movement from the brain to the spinal cord. The weakness is on the opposite side of the body from the stroke and occurs in every patient with an anterior choroidal stroke.
The hemianesthesia is a result of damage to the ventral posterolateral nucleus of the thalamus. This nucleus contains neurons that receive information from the spinal cord about sensation.Damage to this structure causes a decreased ability to feel things on the opposite side of the body. This symptom is less common than weakness, and occurs in roughly half of patients with an anterior choroidal stroke.
The final symptom, homonymous hemianopsia, is caused by damage to the optic tracts and lateral geniculate nucleus of the thalamus. Patients lose the ability to see objects on the left or right side (depending on which anterior choroidal artery is involved) in both eyes. This is an even more uncommon symptom, which occurs in less than 10% of patients with an anterior choroidal stroke.
In reality, strokes of the anterior choroidal artery rarely cause all three symptoms. This is because the anatomy served by the anterior choroidal arteries also receives blood flow from other arteries in the brain.
Aneurysms of the anterior choroidal arteries are rare and will not be discussed in this article.
The anterior choroidal arteries are paired structures that arise from the internal carotid arteries. They supply blood to many important structures within the brain. Stroke is the most common pathological disease related to this blood vessel and frequently causes weakness of the opposite side of the body. High blood pressure is the most common underlying disease seen in people who have a stroke in this vascular distribution.
- Cerebrovascular accident (aka: stroke)
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