Posterior Cerebral Arteries

Posterior cerebral arteries are a paired set of arteries that branch from the basilar artery and deliver oxygenated blood to the occipital lobe, parts of the temporal lobe, and nearby brain structures in Anatomy and Physiology I.

What are Posterior Cerebral Arteries?

The posterior cerebral arteries, or PCAs, are the two main arteries that carry oxygenated blood to the back part of the brain in Anatomy and Physiology I. They usually arise from the terminal end of the basilar artery, which means they are part of the vertebrobasilar system rather than the internal carotid route.

Each PCA supplies the occipital lobe, the region that processes visual input, so damage here can affect sight even when the eyes themselves are fine. They also feed portions of the inferior temporal lobe, where the brain handles parts of memory, recognition, and sensory integration. In some diagrams, you may also see branches going to the thalamus, midbrain, and diencephalon, which shows how far back and how deep this circulation reaches.

A useful way to think about the PCA is as the brain’s posterior supply line. Blood has to reach tissues continuously, because neurons are very sensitive to oxygen and glucose shortages. If flow drops in a PCA territory, the cells in that area can stop working quickly, which is why posterior circulation problems often show up as visual field loss or other neurological symptoms.

The PCAs also connect with the anterior circulation through the posterior communicating arteries as part of the Circle of Willis. That connection matters because it gives the brain a backup route for blood flow if one pathway narrows or is blocked. In lab diagrams, this is the point where you can trace how the brain’s vascular network is built for redundancy, not just single-vessel delivery.

In the course, the PCA usually comes up when you are tracing brain blood supply, labeling arteries on a model, or connecting circulation to nervous system function. If you remember only one thing, it is this: the posterior cerebral arteries feed the visual and posterior regions of the brain, and their location makes them a big part of posterior circulation safety.

Why Posterior Cerebral Arteries matter in Anatomy and Physiology I

Posterior cerebral arteries show up whenever Anatomy and Physiology I connects the cardiovascular system to the nervous system. The brain is one of the most oxygen-hungry organs in the body, so a vessel that supplies the occipital lobe is not just a name to memorize, it is part of the reason vision works at all.

This term also helps you make sense of stroke patterns. If a question describes sudden visual changes, difficulty recognizing objects, or problems tied to the back of the brain, the PCA is one of the first vessels to think about. That link between anatomy and symptoms is a big part of how A&P asks you to reason, not just recite.

The PCA also connects to the Circle of Willis, which is a common topic in CNS circulation because it shows how arteries can support one another. When you understand where the PCA comes from and where it goes, it becomes easier to trace collateral flow and explain why some blockages are more serious than others.

It is also a good example of structure matching function. The vessel’s course to the posterior brain matches the tasks of the tissue it supplies, especially visual processing and parts of memory-related brain function. That makes the PCA useful in diagrams, case questions, and any prompt that asks you to match a vessel with a brain region.

How Posterior Cerebral Arteries connect across the course

Circle of Willis

The posterior cerebral arteries are part of the Circle of Willis through their connections with other major brain arteries. That ring-shaped arrangement gives the brain alternate routes for blood flow if one vessel is narrowed. When you study the PCA, the Circle of Willis shows why brain circulation has built-in backup connections.

Vertebrobasilar System

The posterior cerebral arteries come from the basilar artery, which is a central vessel in the vertebrobasilar system. That means the PCA is part of the posterior blood supply pathway, not the carotid pathway. This connection helps you trace blood from the vertebral arteries into the brain.

Posterior Communicating Artery

The posterior communicating artery links the posterior cerebral artery region with the internal carotid circulation. This connection is one reason the Circle of Willis can provide collateral flow. If you are tracing a brain blood supply diagram, this is the bridge that helps you move between the front and back circulation systems.

Basilar Artery

The basilar artery is the parent vessel from which the posterior cerebral arteries arise at its terminal end. If you know the basilar artery’s path along the brainstem, you can place the PCA in the correct part of the vascular tree. It is often the simplest way to orient yourself on brain circulation diagrams.

Are Posterior Cerebral Arteries on the Anatomy and Physiology I exam?

A diagram label question may show the base of the brain and ask you to identify the artery supplying the occipital lobe. A case prompt may describe sudden loss of part of the visual field and ask which vessel is involved, which points you toward the posterior cerebral arteries. On image-based quizzes, you should be able to trace them from the basilar artery and explain that they nourish the posterior brain, especially the visual cortex. If your instructor uses clinical examples, PCA blockage is the one to connect with visual symptoms and posterior circulation stroke.

Key things to remember about Posterior Cerebral Arteries

• The posterior cerebral arteries are paired vessels that supply the back part of the brain, especially the occipital lobe.

• They arise from the terminal basilar artery, so they belong to the vertebrobasilar circulation.

• Because the occipital lobe handles visual processing, PCA problems often show up as vision changes.

• The PCAs also connect with the Circle of Willis through the posterior communicating arteries.

• In Anatomy and Physiology I, this term is usually used to trace brain blood flow and connect vessel anatomy with neurological symptoms.

Frequently asked questions about Posterior Cerebral Arteries

What are posterior cerebral arteries in Anatomy and Physiology I?

They are the paired arteries that supply oxygenated blood to the posterior brain, including the occipital lobe and parts of the temporal lobe. In A&P, they are usually discussed when you trace cerebral circulation or study the Circle of Willis.

What do the posterior cerebral arteries supply?

They mainly supply the occipital lobe, which processes vision, and portions of the inferior temporal lobe. They can also send branches to deeper structures like the thalamus and midbrain, depending on the branch pattern.

Are posterior cerebral arteries part of the Circle of Willis?

Yes. They connect into the Circle of Willis through the posterior communicating arteries. That connection matters because it helps create alternative routes for blood flow if one pathway is blocked or narrowed.

What happens if the posterior cerebral artery is blocked?

A blockage can cause a posterior circulation stroke, often with visual problems because the occipital lobe is affected. Depending on the exact area involved, memory or other neurological symptoms can also show up.