10.1 Vascular anatomy of the brain

Question 1

Which two arteries supply blood to the brain?

Answer 1

Internal carotid and vertebral

Question 2

How does the carotid artery enter the cranium?

Answer 2

Ascends within the carotid sheath, enters the cranium through the carotid canal

Question 3

How do the vertebral arteries enter the cranium?

Answer 3

Ascend the cervical vertebrae with transverse foramen, enters vertebral canal by penetrating the posterior atlanto-occipital membrane and enters the cranium through the foramen magnum

Question 4

What is the anterior spinal artery and where does it run?

Answer 4

Occupies the anterior median sulcus and runs down the full extent of the spinal cord reinforced by segmental branches at each level of the spinal cord

Question 5

Where would you find the posterior spinal arteries?

Answer 5

Posterolateral sulcus

Question 6

What does the PICA supply?

Answer 6

Major territories in the medulla and cerebellum:
Lateral medulla before going to the back of the cerebellum
Choroid plexus of the 4the ventricle (secretes CSF)
Postero-inferior surface of the cerebellum

Question 7

What are the branches of the basilar artery?

Answer 7

Anterior inferior cerebellar artery
Superior cerebellar artery
Pontine branches

Question 8

What does the anterior inferior cerebellar artery supply?

Answer 8

Anterior part of inferior cerebellum and caudal pons

Question 9

What does the superior cerebellar artery supply?

Answer 9

Supeior surface of the cerebellum, caudal midbrain and rostral pons

Question 10

What separates the posterior and superior cerebellar arteries?

Answer 10

Tentori cerebelli (separates cerebellum form temporal lobe)

Question 11

What do the pontine arteries supply and what is an important branch of these?

Answer 11

Supply the pons, the internal auditory/labrinthine artery supplies the inner ear - occlusion is associated with vertigo

Question 12

What do the anterior spinal arteries and vertebral arteries supply in the lower medulla?

Answer 12

Lower spinal V nucleus and tract
Arcuate fibres and medial lemniscus
Spinothalamic tracts
Pyramids

Question 13

What does the posterior spinal artery supply in the lower medulla?

Answer 13

Gracile and cuneate nucleus of DC system

Question 14

What does the anterior spinal artery supply in the upper medulla

Answer 14

Pyramids (corticospinal tract)
Medial lemniscus (DC system)
Tectospinal (and medial long. fasiculus)
Hypoglossal nucleus

Question 15

What does the PICA supply in upper medulla?

Answer 15

Vestibular nuclei 
Olivocerebellar fibres 
Spinal V nucleus 
Solitary nucleus and tract 
Nucleus ambigus 
Spinothalamic tract
Descending sympathetic fibres

Question 16

If you have an anterior spinal artery occlusion/bleed what will you get?

Answer 16

Medial medullary syndrome
C/L hemiparesis (pyramid)
C/L impairment of sensation of tactile discrimination, proprioception (medial lemniscus)
I/L paralysis of tongue muscles (hypoglossal n + nucleus)

Question 17

If you have a PICA bleed/occlusion what will you have?

Answer 17

Lateral medullary syndrome (Wallenbergs)
- Dysphagia (n.ambiguus)
I/L loss of pain and temp to face (spinal V)
Vertigo, nausea, vomiting, nystagmus (vestibular nerve)
Horners syndrome (sympathetics)
I/L limb and gait ataxia (dorsal spinocerebellar, ICP and olivocerebellar)
C/L loss of pain and temp (spinothalamic)

Question 18

What are the symptoms of Horners syndrome and wha causes it?

Answer 18

Ptosis, miosis, anhidrosis

Due to loss of sympathetic innervation

Question 19

What is retained in locked in syndrome and why?

Answer 19

Oculomotor and trochlear nerve function
Hearing
The nuclei for the nerves involved are not affected - oculomotor in the midbrain and the cochlear nerves and superior olivary nerve are laterally placed on the pons

Question 20

what does the posterior cerebral artery supply?

Answer 20

tectum, most of cerebral peduncle (except most medial), oculomotor nucleus and Edinger Westphal nucleus

Question 21

What is the Edinger Westphal nucleus?

Answer 21

accessory oculomotor nucleus and is the parasympathetic pre-ganglionic nucleus that innervates the iris sphincter muscle and the ciliary muscle.

Question 22

What will you get with an occlusion/bleed of the posterior cerebral artery (mid brain branches)?

Answer 22

Weber’s syndrome: necrosis of teh peduncle and oculomotor nerve
I/L opthalmoplegia, ptosis, dilation of pupil, no light response or accommodation (CN III nucleus ad nerve)
C/L paralysis of arm and leg (corticospinal)
C/L paralysis of lower face and tongue (corticobulbar)

Question 23

What will you get with occlusion/bleed of posterior cerebral artery affecting the lemnisci and red nucleus?

Answer 23

Benedikts syndrome
C/L involuntary limb movements
C/L loss of sensation

Question 24

Where does the internal carotid lie?

Answer 24

Immediately posterior to the optic nerve

Question 25

What are the branches of the internal carotid artery and how do they end?

Answer 25

Opthalmic
Posterior communicating
Anterior choroidal

End by dividing into anterior and middle cerebral arteries

Question 26

Where does the anterior cerebral artery run and what does it supply?

Answer 26

In the cingulate sulcus, just above corpus callosum as far as the parieto-occipital sulcus

Supplies the medial aspect of frontal and parietal lobes and a narrow strip adjacent to the inter-hemispheric sulcus
ALso supplies olfactory bulbs, tracts and anterior hypothalamus

Question 27

Where does the middle cerebral artery run, what are its branches and what does it supply?

Answer 27

Runs laterally between frontal and temporal lobes to enter the lateral fissure
Subdivides into 2 major branches for the
1. frontal and anterior parietal lobes
2. temporal and posterior parietal lobes

Supplies lateral surface of the cerebral cortex including the frontal, parietal and antero-lateral occipital lobes and the insula

Question 28

What will you get with bleed/occlusion of anterior cerebral artery?

Answer 28

C/L hemiplegia and somatosensory loss affecting the leg and food (paracentral lobe)

Question 29

What will you get with bleed/occlusion of middle cerebral artery?

Answer 29

C/L hemiplegia and ocmatosensory of upper limb and head, aphasia, multiple sensory losses

Question 30

What will you get with bleed/occlusion of posterior cerebral artery

Answer 30

C/L hemianopsia (damage to V1-3 and occipital cortex)

Question 31

How is blood drained from the brain

Answer 31

Via the venous sinuses which is located between 2 layers of dura
Mostly via the sigmoid sinus > internal jugular vein
Cavernous sinus drains central face and orbit