L2 - HARC: Vasculature of the CNS

Question 1

What are the 3 main arteries supplying the head and neck?

Answer 1

Common Carotid

• External CC
• Internal CC

Subclavian
- Vertebral

Question 2

Where does bifurcation of CC artery occur?

Answer 2

C4

Question 3

What are the meninges of the brain?

Answer 3

3 layers of protective tissue covering brain:

• dura mater
• arachnoid mater
• pia mater

Question 4

What does the ECa commonly supply?

Answer 4

Predominantly extra-cranial structures

Exception: supplies meninges intracranially via the middle meningeal artery

Question 5

What 2 systems are joined together by the Cerebral arterial circle (of Willis)?

Answer 5

1. Carotid (anterior) system

2. Vertebrobasilar (posterior)

Question 6

What makes up the anterior carotid system?

Answer 6

Right Internal carotid artery

Left ICa

Question 7

What makes up the posterior vertebrobasilar system?

Answer 7

Vertebral arteries joining to become basilar artery.

run in transverse foramina of first 6 vertebrate

Question 8

Define anastomosis?

Answer 8

connection between two normally divergent structures

Question 9

Where does the ICa enter skull?

Answer 9

Enters via carotid canal

Passes over the foramen lacerum

Question 10

What is the foramen lacerum?

Answer 10

hole in base of skull. filled with connective tissue and meningeal branches from ascending pharyngeal artery and emmisary veins from cavernous sinus to pterygoid venous plexus.

Question 11

What is the carotid siphon?

Answer 11

curve in cavernous segment. portion of artery is surrounded by filaments of the sympathetic trunk. Lateral side - abducent CN VI

Question 12

What is the origin of the vertebrobasilar system?

Answer 12

First part of subclavian artery

Question 13

How does the vertebrobasilar system enter the skull?

Answer 13

Foramen magnum.

forms the basilar artery on anterior surface of brain stem, lying on top of clivus of the cranial base

Question 14

What arteries make up the cerebral arterial supply?

Answer 14

Anterior cerebral artery
Posterior (PCa)
Middle (MCa)

Question 15

Describe passage of Anterior cerebral artery

Answer 15

forward, medially under corpus callosum.

then superiorly and posterioly along superior surface of corpus callosum?

Question 16

What is the corpus callosum?

Answer 16

thick nerve tract consisting of a flat bundle of commissural fibers, beneath cerebral cortex in brain.

Question 17

What areas does the anterior cerebral artery supply?

Answer 17

Frontal lobes.
Medial aspect of parietal lobes
Optic chiasm
Lower limb motor and sensory cortexes.

Question 18

Describe passage of Posterior cerebral artery?

Answer 18

PCa terminal branch of basilar artery.

Passes posterioly otw supplying parietal lobe.

Supplies occiptal lobe - visual cortex

Question 19

Describe the passage of the middle cerebral artery?

Answer 19

Passes laterally towards temporal lobe up to lateral aspects of cerebrum.
Initially travels through lateral fissure.

Question 20

What areas and lobes does the middle cerebral artery supply?

Answer 20

Temporal, parietal and occipital lobes.
Broca’s area- speech
Wernicke’s - language comprehension
Head and neck areas of motor and sensory cortexes.

Question 21

Give examples of branches of the CoW which supply internal substance of the brain?

Answer 21

Lenticulostriate arteries

Medial striate

chorodial

Question 22

Describe the lenticulostriate arteries?

Answer 22

from MCA.

Lateral striate arteries.

Question 23

Describe the Medial striate arteries?

Answer 23

from Anterior cerebral artery.

reccurent artery of Heubner

Question 24

Describe the chorodial arteries?

Answer 24

Ant. (MCa) - first branch

Post. (PCa) - first group rather than singular arteries

Question 25

What do the lenticulostriate arteries supply?

Answer 25

Basal ganglia Thalamus Internal capsule

Question 26

Why are lenticulostriate arteries associated with stroke?

Answer 26

LCS.a : small, penetrating BV supplying blood to most sub cortical structures. Occlusions in these are reffered to as lacunar strokes. Causes motor and sensory disruption.

Question 27

What are examples of cerebellar arteries?

Answer 27

Superior cerebellar artery Anterior Inferior cerebellar artery. Posterior Inferior cerebellar artery.

Question 28

Infarct definition?

Answer 28

small localised area of dead tissue resulting from failure of blood supply.

Question 29

Infarction of Superior cerebellar artery may affect what structures?

Answer 29

Superior cerebellum | Posterolateral midbrain

Question 30

Infarction in AICa may affect what structures?

Answer 30

Anteriorinferior cerebellum Posterolateral pons Inner ear

Question 31

Infarction in PICa may affect which structures?

Answer 31

Posteroinferior cerebellum

Question 32

Neurological defects that could arise due to infarction in SCa?

Answer 32

SCa - ataxia (gait), dysarthria (difficult articulation of speech otherwise linguistically OK), nystagmus (vol, invol eye movement), nausea, vomming, headache and vertigo

Question 33

Neurological defects that could arise due to infarction in AICa?

Answer 33

vertigo, nausea, intolerance of head motion. Horner's syndrome: constriction of pupil (miosis), drooping of upper eyelid (ptosis) and anhidrosis (no face sweating) unilateral hearing loss ipsilateral facial paralysis.

Question 34

Neurological defects that could arise due to infarction in PICa?

Answer 34

Headache

Question 35

What bones make up the Pterion?

Answer 35

Pterion: 1. Temporal 2. Sphenoid 3. Frontal 4. Parietal

Question 36

Where does the middle meningeal a. enter the skull?

Answer 36

Foramen spinosum. | Largest meningeal a.

Question 37

Briefly, how are ventricles formed?

Answer 37

Ventricles: spaces in brain, filled with CSF Central canal of neural tube dilates to form ventricles Choroid plexus -- CSF - lateral, 3rd & 4th ventricles

Question 38

Describe the pathway of CSF flow?

Answer 38

``` Lateral ventricle - Interventricular foramina Third Ventricle - cerebral aqueduct Fourth Ventricle - lateral and median apertures Subarachnoid space Arachnoid villi of dural venous sinuses - Venous blood Heart and lungs - arterial blood back to 3rd, 4th and lateral ```

Question 39

What are the internal veins involved in head and neck venous drainage?

Answer 39

``` Cavernous sinus facial vein superior sagittal sinus inferior sagittal sinus confluence of sinuses ```

Question 40

what are the external veins involved in head and neck venous drainage?

Answer 40

Angular vein | Retromandibular vein

Question 41

Where do all veins involved in head and neck drain into?

Answer 41

Internal jugular vein

Question 42

What two layers form dural venous sinuses?

Answer 42

1. Periosteal layer - superficial and attached to the skull 2. Meningeal - deep and projecting through cranial cavity Spaces created between the two layers collect venous blood from the brain aka 'dural venous sinuses'

Question 43

Describe the cavernous sinus?

Answer 43

One of the dural venous sinuses of the head. Network of veins that sit in a cavity. approx 1 x 2cm

Question 44

What passed through the cavernous sinus?

Answer 44

Carotid siphon of ICa. | CN III, IV, V (v1 & v2)

Question 45

Describe an Epidural Haemorrhage?

Answer 45

Collection of blood between inner skull surface and outer dura (endosteal layer). Source of bleeding is most commonly a torn middle meningeal artery.

Question 46

Describe the look of an epidural haemorrhage?

Answer 46

Biconvex shape. Can cause mass effect with herniation. Don't cross sutures as periosteum crosses through the suture continuous with other periosteal layer.

Question 47

Middle meningeal artery is a branch of the....

Answer 47

maxillary artery from external carotid artery.

Question 48

Describe a subdural haematoma?

Answer 48

Bleeding occurs between dura and arachnoid. Bleeding is under skull and outside brain. Pressure on brain increases as blood accumulates.

Question 49

Describe a subarachnoid haemorrhage?

Answer 49

Bleeding into subarachnoid space. Area between arachnoid membrane and pia mater surrounding brain. Look out for star like shape in CT.

Question 50

What is hydrocephalus?

Answer 50

Accumulation of cerebrospinal fluid within brain.