Cranial cavity blood supply

Question 1

Vertebral a.

Answer 1

Distribution:
• Brain
• Spinal cord
• Vertebral column

Branches:
• Posterior inferior cerebellar
• Spinal arteries
• Continues as basilar artery (formed by union of right and left vertebral arteries)

Comment:
• Large arteries do not by themselves supply structures, but do so through their branches

Question 2

Basilar a.

Answer 2

Course:
• Unpaired (midline) vessel ascends on anterior (ventral) surface of pons

Distribution:
• Pons
• Cerebellum

Branches:
• Pontine
• Anterior inferior cerebellar
• Superior cerebellar
• Posterior cerebral

Question 3

Posterior cerebral a. and branches

Answer 3

Origin:
• Basilar

Course:
• Paired vessels pass laterally around cerebral peduncles

Distribution:
• Temporal and occipital lobes of cerebral cortex

Comment:
• Oculomotor nerve (CN III) passes between it and superior cerebellar artery

Question 4

Posterior communicating a.

Answer 4

Origin:
• Internal carotid and basilar arteries

Course:
• Paired vessel connects basilar artery with internal carotid artery on each side

Question 5

Internal carotid a.

Answer 5

Course:
• Ascends in neck to base of cranium
• Enters cranial cavity via carotid canal

Distribution:
• Eye
• Cerebrum
• Cerebral arterial circle (of Willis)

Branches:
• Ophthalmic
• Anterior cerebral
• Middle cerebral

Comment:
• Enclosed in carotid sheath
• Carotid sheath is a fascial sleeve which contains common and internal carotid arteries, internal jugular vein, vagus nerve (CN X), and lymphatic channels

Question 6

Middle cerebral a. and branches

Answer 6

Origin:
• Internal carotid

Course:
• Paired vessels course in lateral sulcus of each cerebral hemisphere

Distribution:
• Lateral aspects of frontal, parietal, and temporal lobes of cerebral cortex

Question 7

Anterior cerebral a. and branches

Answer 7

Origin:
• Internal carotid

Course:
• Passes anteriorly along medial aspect of frontal lobe of cerebral cortex

Comment:
• Medial aspect of frontal lobe of cerebral cortex

Question 8

Anterior communicating a.

Answer 8

Origin:
• Anterior cerebral

Course:
• Short, unpaired vessel
• Connects paired anterior cerebral arteries

Question 9

Cerebral arterial circle

Answer 9

Origin:
• Internal carotid and basilar arteries

Course:
• Circular anastomosis on ventral surface of brain

Also known as:
• Circle of Willis

Comment:
• Branches include paired anterior and posterior cerebral arteries, posterior communicating arteries, and unpaired anterior communicating artery
• Anastomosis refers to the end-to-end union of vessels