Anterior choroidal artery

The anterior choroidal artery originates from the internal carotid artery. However, it may (rarely) arise from the middle cerebral artery.
Structure.
The anterior choroidal artery originates from the distal carotid artery 5 mm after the origin of the posterior communicating artery and just before the carotid terminus. It serves structures in the prosencephalon, diencephalon, and mesencephalon: 
Clinical significance.
The full extent of the damage caused by occlusion of the anterior choroidal artery is not known. However, studies show that the interruption of blood flow from this vessel can result in hemiplegia on the contralateral (opposite) side of the body, contralateral hemi-hypoesthesia, and homonymous hemianopsia. These symptoms are thought to arise from ischemic damage to the posterior limb of the internal capsule, thalamus, and optic chiasm/optic tract. However, the posterior limb of the internal capsule also receives lenticulostriate arteries from the middle cerebral artery, thus creating partially redundant supply.