Visual cortex is supplied by -a) Anterior cerebral arerysb) Medial cerebral arteryc) Posterior cerebral arteryd) Anterior inferior cerebellar artery
First, I need to recall the anatomy of the cerebral arteries. The visual cortex is located in the occipital lobe, specifically in the calcarine sulcus area. The posterior cerebral artery (PCA) is known to supply the occipital lobe, including the primary visual cortex. The PCA is part of the vertebrobasilar system and arises from the basilar artery.
The anterior cerebral artery (ACA) supplies the medial aspects of the frontal and parietal lobes, so that's probably not the answer. The middle cerebral artery (MCA) is the largest branch of the internal carotid artery and supplies much of the lateral surface of the frontal, parietal, and temporal lobes. The anterior inferior cerebellar artery (AICA) is a branch of the basilar artery but supplies the cerebellum and parts of the brainstem, not the occipital lobe.
So the correct answer should be option C, posterior cerebral artery. The other options don't supply the visual cortex. The key here is remembering that the PCA is responsible for the occipital lobe, including the visual cortex. A clinical pearl might be that a PCA stroke can lead to homonymous hemianopia, which is a classic sign of visual cortex damage. Also, the ACA and MCA strokes have different symptoms, like motor or sensory deficits, whereas PCA issues are more about vision.
**Core Concept**
The visual cortex, located in the occipital lobe's calcarine sulcus, is primarily supplied by the **posterior cerebral artery (PCA)**. This artery originates from the basilar artery and is part of the vertebrobasilar system, ensuring blood flow to the posterior brain regions, including the visual processing areas.
**Why the Correct Answer is Right**
The **posterior cerebral artery (PCA)** is the primary supplier to the visual cortex. It arises from the basilar artery and anastomoses with the posterior communicating artery. The PCA also supplies the medial temporal and occipital lobes, including the primary visual cortex (Brodmann area 17) and visual association areas. Occlusion of the PCA can lead to homonymous hemianopia, a hallmark deficit in visual processing.
**Why Each Wrong Option is Incorrect**
**Option A:** *Anterior cerebral artery (ACA)* supplies medial frontal and parietal lobes but not the occipital lobe.
**Option B:** *Middle cerebral artery (MCA)* supplies lateral frontal, parietal, and temporal lobes but does not reach the visual cortex.
**Option D:** *Anterior inferior cerebellar artery (AICA)* supplies the cerebellum and brainstem, not cortical structures.
**Clinical Pearl / High-Yield Fact**
A PCA stroke often causes **homonymous hemianopia** (loss of vision in the same visual field of both eyes). Remember the "PCA → posterior → occipital → vision" association. Avoid confusing ACA/MCA territories, which involve motor/sensory deficits rather than visual loss.
**Correct Answer: C. Posterior cerebral artery**