Vertebrobasilar system — Flashcards

Flashcard 1: Which vessel of the Circle of Willis arises from the terminal bifurcation of the basilar artery?

Answer: Posterior cerebral artery

Extra: The posterior cerebral artery (PCA) arises from the terminal bifurcation of the basilar artery. It supplies the occipital lobe and the inferior portion of the temporal lobe. It is connected to the internal carotid artery via the posterior communicating artery, completing the posterior part of the Circle of Willis.

Flashcard 2: What artery supplies the medial and lateral midbrain? _____

Answer: Posterior cerebral artery

Flashcard 3: The _____ branches of the posterior cerebral artery supply the splenium, parahippocampal gyrus, and fusiform gyrus

Answer: cortical

Extra: The **cortical branches** of the PCA supply the splenium of the corpus callosum and the medial and inferior surfaces of the temporal and occipital lobes (including the parahippocampal and fusiform gyri). The **central (deep) branches** (e.g., thalamogeniculate, thalamoperforating) supply the thalamus and midbrain.

Flashcard 4: What arteries (2) supply the medial medulla? _____

Answer: Anterior spinal artery or vertebral artery

Flashcard 5: Which cerebral artery supplies the occipital lobe? _____

Answer: Posterior cerebral artery

Flashcard 6: Which artery connects the internal carotid artery to the posterior cerebral artery in the Circle of Willis?

Answer: Posterior communicating artery

Extra: Aneurysms of the posterior communicating artery (PCoA) are a common cause of third nerve (oculomotor) palsy.

Flashcard 7: What structure is most commonly compressed by an aneurysm of the anterior communicating artery?

Answer: Optic chiasm compression, resulting in bitemporal hemianopia.

Extra: Aneurysms of the anterior communicating artery (ACom) are the most common site of Berry aneurysms in the Circle of Willis. Due to their location, they can compress the optic chiasm, leading to visual field defects.

Flashcard 8: An aneurysm of which artery is most commonly associated with a CN III palsy?

Answer: CN III (Oculomotor nerve) palsy

Extra: Aneurysms of the posterior communicating artery (PCoA) typically cause a CN III palsy with pupil involvement (mydriasis), because the parasympathetic fibers are superficial on the nerve. Findings: Ptosis, "down and out" eye position, and a dilated pupil.

Flashcard 9: Where do saccular "berry" aneurysms tend to occur?

Answer: bifurcations in Circle of Willis; especially anterior and posterior communicating arteries

Flashcard 10: Identify the branch of the vertebral artery labeled as number 3 in the provided image.

Answer: posterior spinal arteries