Cerebral Arterial Blood Flow & Circle of Willis

19 Question & Answer flashcards covering the vertebral and internal carotid arteries, their branches, the basilar artery, cerebellar arteries, cranial nerve III relationship, and the composition of the Circle of Willis.

From which part of the subclavian artery does the vertebral artery typically arise?

The posterior superior aspect of the first part of the subclavian artery.

On which side and from which vessel can the vertebral artery sometimes arise directly?

On the left side, directly from the aortic arch.

At which cervical vertebral level does the vertebral artery enter the transverse foramen?

C6 (not C7).

After leaving the C1 transverse foramen, over which bony structure does the vertebral artery course before entering the foramen magnum?

It runs medially and superiorly across the posterior arch of the atlas through its sulcus (groove).

What artery is formed by the union of the right and left vertebral arteries within the cranial cavity?

The basilar artery.

From where does the internal carotid artery arise?

From the common carotid artery at the upper border of the thyroid cartilage.

Through which canal does the internal carotid artery enter the middle cranial fossa?

The carotid canal.

Into which two terminal branches does the internal carotid artery divide?

The anterior cerebral artery and the middle cerebral artery.

How many branches does the internal carotid artery give off in the neck?

None—there are no branches in the neck.

Which cerebellar artery is the first branch of each vertebral artery?

The posterior inferior cerebellar artery (PICA).

Name the two cerebellar arteries that branch from the basilar artery before it divides at the midbrain-pons junction.

The anterior inferior cerebellar arteries (AICA) and the superior cerebellar arteries (SCA).

At which brainstem border does the basilar artery terminate, and into which arteries does it split?

At the border of the pons and midbrain; it splits into a pair of posterior cerebral arteries.

Which cranial nerve usually exits between the posterior cerebral artery and the superior cerebellar artery?

The oculomotor nerve (cranial nerve III).

What single vessel connects the right and left anterior cerebral arteries?

The anterior communicating artery.

Which arteries connect the posterior cerebral arteries to the internal carotid system?

The posterior communicating arteries.

List all the vessels that constitute the Circle of Willis.

Right & left posterior cerebral arteries, right & left posterior communicating arteries, right & left internal carotid arteries, right & left anterior cerebral arteries, and the single anterior communicating artery.

Which cerebral arteries arise from the internal carotid artery?

The anterior cerebral arteries and the middle cerebral arteries.

Besides forming the basilar artery, which specific cerebellar arteries arise directly from the vertebral arteries?

The posterior inferior cerebellar arteries (PICA).

From which artery do the posterior communicating arteries arise?

The posterior cerebral arteries.