71. POSTERIOR BLOOD SUPPLY. CLINICAL NOTES

Question 1

How is the brain’s posterior circulation supplied?

Answer 1

The brain’s posterior circulation is supplied primarily by the branches of the vertebral arteries.

Question 2

Where do the vertebral arteries arise from?

Answer 2

The vertebral arteries arise from the subclavian arteries and ascend in the foramen transversarium of the cervical vertebrae.

Question 3

What happens when the vertebral arteries merge?

Answer 3

The vertebral arteries merge to form the basilar artery at the level of the pons.

Question 4

What is the basilar artery’s role?

Answer 4

The basilar artery is the main supply to the brainstem, cerebellum, and parts of the occipital lobe. It gives off the posterior cerebral arteries that supply the posterior parts of the brain.

Question 5

What can a posterior cerebral artery stroke cause?

Answer 5

A posterior cerebral artery stroke can cause visual disturbances, as the occipital lobe, where visual processing takes place, is fed by it.

Question 6

What are transient ischemic attacks (TIAs)?

Answer 6

Transient ischemic attacks (TIAs) are triggered by vertebrobasilar insufficiency due to diminished blood supply of the posterior circulation, leading to dizziness, visual loss, and ataxia.