3) Arterial Supply to the Brain

Question 1

Describe the two sources that make up the Arterial Supply to the brain. And what are they made from

Answer 1

The brain receives arterial blood supply from 2 different sources:
> Anterior Circulation - Made up by 2 major branches of ICA, Supplies a majority of the Cerebral Hemispheres
> Posterior Circulation - Made up by Vertebral Arteries and it’s branches, Supplies :
- Brain stem
- Cerebellum
- Temporal and Occipital Lobe

Question 2

What 2 Branches of the ICA makes up the Anterior Circulation ?

Answer 2

Middle Cerebral Artery
> Direct Continuation of ICA
> Cortical Branches emerge from lateral fissure to supply the lateral aspect of the cerebral hemisphere - Supplies Lateral Frontal and Parietal Hemispheres ( Therefore affects lateral sensory and motor Homunculus)
> Deep Branches ( Lenticulostriate Arteries ) supply deep grey matter including the Lentiform Nucleus and Caudate as well as the internal capsule - They supply major motor pathways

Anterior Cerebral Artery
> Left and Right ACA anastomose at the mid line via Anterior Communicating Artery
> They supply the medial Frontal and Parietal Lobes
> Vessels loop over Corpus Callosum

Question 3

What forms the Circle of Willis ?

Answer 3

• 2 Posterior Communicating arteries connecting to the Anterior circulation
• Anterior communicating arteries join the circle together

Question 4

Describe the formation of the Anterior Spinal Artery.

Answer 4

Subclavian -> Vertebral Arteries -> Foramen Magnum
At the Foramen Magnum, the vertebral arteries give off a branch each
The two branch merges to form Ant.Spinal Artery

Question 5

What does the Ant.Spinal Artery Supply ?

Answer 5

Supply Ant.2/3 of the Spinal Cord

Question 6

Describe the formation of Basilar Artery

Answer 6

Merging for 2 Vertebral Arteries

Question 7

List the Branches of the Basilar Artery and what they supply ?

Answer 7

Posterior Cerebral Arteries -> Terminal Bifurication forms 2 - They supply Occipital, Inf. Temporal and Thalamus

Pontine Arteries -> Supply the Pons

Superior Cerebral Arteries -> Supply superior aspect cerebellum and mid brain en passant

Anterior Inferior Cerebral Arteries -> Supply Anterior and inferior aspect of the Cerebellum