Blood Supply to the Brain

Question 1

What is the average brain blood flow?

Answer 1

46ml/100g of brain per minute

Question 2

How many seconds of no oxygen leads to unconsciousness?

Answer 2

20s

Question 3

What length of time of no oxygen leads to permanent unconsciousness?

Answer 3

> 5 mins

Question 4

What supplies 80% of cerebral blood flow?

Answer 4

Carotids

Question 5

Where does the remaining 20% of arterial supply come from?

Answer 5

Vertebrals

Question 6

Are the anterior and posterior communicating arteries open or closed in normal angiogram?

Answer 6

Closed as doesn’t need to be open in normal situations. Pressure in left and right side are same.

Question 7

What does the MCA supply?

Answer 7

Lenticulostriate arteries to the deep basal ganglia

Question 8

What are the areas called when there’s overlap + anastomose areas e.g. posterior cerebral and anterior cerebral artery?

Answer 8

Watershed

Question 9

In posterior circulation, what do the vertebral arteries supply?

Answer 9

Spinal Cord
Dorsal medulla (PICA)

Question 10

In posterior circulation, what do the basilar arteries supply?

Answer 10

Pons

Cerebellum

Question 11

In posterior circulation, what does the posterior cerebral artery supply?

Answer 11

Inferior and medial aspect of temporal and occipital cortex
Thalamus and posterior internal capsule
Midbrain

Question 12

Where do superficial cerebral veins cross?

Answer 12

Subarachnoid space

Question 13

Where do superficial cerebral veins pierce?

Answer 13

Dura

Question 14

After superficial cerebral veins pierce the dura, they enter where?

Answer 14

intracranial (dural) venous sinuses

Question 15

What do arachnoid granulations allow?

Answer 15

Allow CSF to flow into venous blood of sinuses but prevent backflow of blood into the subarachnoid space

Question 16

What drains the cerebellum?

Answer 16

superior and inferior cerebellar veins

Question 17

Causes of ischaemic stroke?

Answer 17

Atherosclerosis

Embolism

Question 18

Causes of cerebral haemorrhage?

Answer 18

Trauma

Spontaneous

Question 19

Symptoms of MCA stroke in dominant side?

Answer 19

Global aphasia

Sensorimotor loss on contralateral face, upper limb and trunk

Question 20

Symptoms of PCA Stroke?

Answer 20

 Contralateral homonymous hemianopia (blindness over half the field of vision,
affecting the same place in both eyes).
 Reading and writing deficits.
 Impaired memory.

Question 21

Symptoms of MCA stroke in non dominant side?

Answer 21

Neglect syndrome

Question 22

Symptoms of ACA Stroke

Answer 22

 Contralateral sensorimotor loss below the waist.
 Urinary incontinence.
 Personality defects (frontal lobe).
 Split-brain syndrome (lack of coordination between L and R side).

Question 23

Define transient ischaemic attack

Answer 23

temporary loss of brain function (<30 mins)

Question 24

How long does it take for a TCA to resolve and how long does it take to happen?

Answer 24

Sudden onset and resolves within 24 hours

Question 25

What is a TIA a warning sign of?

Answer 25

Stroke or Heart Attack

Question 26

What are anterior symptoms of TIA?

Answer 26

Motor weakness Hemo-sensory loss Dysarthria (speech)

Question 27

What are posterior symptoms of TIA?

Answer 27

vertigo diplopia ataxia amnesia

Question 28

What is an Extra-Axial bleed?

Answer 28

A bleed outside of the brain tissue

Question 29

Where is an Extra-Axial Bleed located?

Answer 29

Between any layers of the meninges

Question 30

Where does an Extradural Hematoma occur?

Answer 30

Between skull and dura mater

Question 31

What is Extradural Hematoma caused by?

Answer 31

Trauma

Question 32

What do patients experience after Extradural Hematoma?

Answer 32

Lucid period after blow, followed by unconsciousness

Question 33

Is the bleed slow or fast in extradural hematoma?

Answer 33

Rapid as it is artery

Question 34

Which artery does extradural hematoma usually occur in?

Answer 34

meningeal artery

Question 35

Symptoms of extradural hematoma?

Answer 35

- Increases intracranial pressure to compresses CN III. - Weakness of contralateral extremities. - Loss of visual field opposite to lesion (PCA compression).

Question 36

Where does expansion of extradural hematoma stop?

Answer 36

Sutures as dura is better attacked but able to then press inwards

Question 37

Where does subdural hematoma occur?

Answer 37

Between dura mater and subarachnoid layer

Question 38

What causes subdural hematoma?

Answer 38

Trauma or ageing

Question 39

Which has a slower onset? Subdural hematoma or extradural hematoma

Answer 39

Subdural hematoma as it is from venous blood

Question 40

Symptoms of subdural hematoma?

Answer 40

``` Irritability Seizures Headache Numbness Disorientation ```

Question 41

What shape do subdural hematomas have?

Answer 41

convex shape

Question 42

Can subdural hematomas cross suture lines?

Answer 42

Yes

Question 43

How to diagnose subdural hematoma?

Answer 43

CT scan

Question 44

Where are subarachnoid hematomas located?

Answer 44

Between arachnoid layer and pia mater

Question 45

Symptoms of subarachnoid hematoma?

Answer 45

Severe headache Vomiting Confusion Lowered level of consciousness

Question 46

How to diagnose subarachnoid hematoma?

Answer 46

Lumbar puncture

Question 47

What is a cerebral aneurysm?

Answer 47

Bulge in a blood vessel due to wall weakness

Question 48

What shape are cerebral aneurysms?

Answer 48

berry or saccular shaped

Question 49

Are men or women at higher risk from cerebral aneurysms?

Answer 49

Women

Question 50

What is a cerebral arteriovenous malformation?

Answer 50

Abnormalities in the capillary bed structure of the cerebellum?

Question 51

Common symptoms of AVM?

Answer 51

Headaches + seizures

Question 52

What is Lateral Medullary syndrome?

Answer 52

Occulsion of the PICA (Wallenberg syndrome)

Question 53

What does Lateral Medullary Syndrome cause damage to?

Answer 53

Lateral medula causing: vertigo, nystagmus + nausea