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NSx Neuroanatomy > CNS Blood Supply COPY > Flashcards

CNS Blood Supply COPY Flashcards

1
Q

What proportion of CO is received by brain?

What proportion of O2 does it use?

A

17%

20%

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2
Q

Describe the intracranial course of the carotid artery

A

Enters the skull in the middle cranial fossa beside the dorsum sellae of the sphenoid.

Carotid siphon- anterior, superior at medial ACP, enters subarachnoid space and courses posteriorly below optic nerve turning upwards lateral to optic chiasm

Divides into terminal branches below anterior perforated substance

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3
Q

Which artery supplies the neurohypophysis?

A

Inferior hypophyseal

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4
Q

What do the superior hypophyseal arteries supply?

A

Enter the median eminence of the hypothalamus.

Break up into capillary loops into which hypothalamic releasing factors gain access.

The capillary loops drain through small hypophyseal portal veins into the capillaries of the anterior lobe.

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5
Q

Where is the ophthalmic artery given off?

A

Immediately after the ICA enters the subarachnoid space

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6
Q

What structures are supplied by the ophthalmic artery?

A

Eye and other orbital contents

Frontal area of the scalp

Frontal and ethmoid paranasal sinuses

Parts of the nose

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7
Q

What are the branches of the ophthalmic artery?

DR MCLESSI

A

D: dorsal nasal artery

R: (central) retinal artery

M: muscular artery

C: ciliary arteries (long, short and anterior)

L: lacrimal artery

E: ethmoidal arteries (anterior and posterior)

S: supraorbital artery

S: supratrochlear artery (frontal artery)

I: internal palpebral artery

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8
Q

Which of the branches of the ophthalmic artery supply the nose?

A

Anterior and posterior ethmoidal

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9
Q

Passage of the anterior choroidal artery

A

Posterior- along optic tract, choroid fissue at medial edge of temporal lobe

Branches to optic tract, uncus, amygdala, hippocampus, globus pallidus, lateral geniculate body and ventral part of the internal capsule.

Terminal branches→ choroid plexus in temporal horn anastomosing with posterior choroidal

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10
Q

Neurological deficit with ICA occlusion

A

Blindness of ipsilateral eye

Loss of contralateral half of visual field.

Contralateral hemiplegia and hemianopia with global aphasia

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11
Q

Neurological deficit with anterior choroidal occlusion

A

Contralateral hemiplegia and sensory abnormalities (internal capsule)

Contralateral homonymous heminaopia

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12
Q

Passage of MCA

A

Runs deep in the lateral sulcus between the frontal and temporal lobes

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13
Q
A
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14
Q

What branch of the ACA is given off just proximal to the AComm?

A

Medial striate artery (recurrent artery of Heubner)

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15
Q

What is supplied by the recurrent artery of Heubner?

A

aka Medial striate artery

Penetrates the anterior perforated substance to supply the ventral part of the head of the caudate nucleus, the adjacent part of the putamen and the anterior limb and genu of the internal capsule

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16
Q

Branches of the ACA

A

Ascends in the longitudinal fissure and bends backwards around the genu of the corpus callosum.

Supplies medial part of the orbital sufrace of frontal lobe including the olfactory bulb and tract.

Continues along the upper surface of the corpus callosum as the pericallosal artery and a large branch, the callosmarginal artery follows the cingulate sulcus.

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17
Q

Why does a unilateral MCA lesion cause no loss of hearing even though the auditory cortex is including in the MCA territory?

A

Due to the bilateral cortical projection.

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18
Q

Why does a lesion in the internal capsule not cause aphasia?

A

Because the connections of the language areas with the contralateral hemisphere are intact.

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19
Q

Features of anterior cerebral artery occlusion

A

Contralateral paralysis of leg and perineum.

May have urinary incontinence caused by inadequate perineal sensation.

May also have contralateral facial weakness due to corticofugal fibres.

Infarction of olfactory lobe may cause anosmia.

Mental confusion and dysphasia may result ?due to loss of function in the prefrontal cortex, cingulate gyrus and SMA

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20
Q

How does the vertebral artery enter the subarachnoid sapce?

A

Pierces the atlanto-occpital membrane then the arachnoid and dura mater at the foramen magenum

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21
Q

Whence does the single anterior spinal artery arise?

A

From a contribution from each vertebral artery.

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22
Q

From what do the posterior spinal arteries arise

A

Either as a branch of the vertebral or PICA.

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23
Q

Passage of PICA

A

Irregular course between medulla and cerebellum.

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24
Q

Branches of PICA

A

Distributed to posterior parts of the cerebellar hemisphere, inferior vermis, central nuclei of cerebellum and choroid plexus of the fourth ventricle.

There are also important medullary branches to the dorsolateral medulla

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25
Q

Under which layer of meninges do the CNS arteries lie?

A

Subarachnoid

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26
Q

Where do the vertebral arteries unite?

A

Pontomedullary junction

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27
Q

What structures are supplied by PCA?

A

Midbrain

Occipital lobe

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28
Q

Where does the anterior spinal artery originate?

A

Anterior to the medulla from two contributory branches of the vertebral artery.

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29
Q

Structures supplied by PICA

A

Lateral medulla

Posteroinferior cerebellum

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30
Q

What proportion of SC is supplied by ASA?

A

Anterior 2/3rds

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31
Q

How do segmental arteries enter the SC?

A

Via the spinal nerves, divide into anterior and posterior radicular arteries passing down the ventral and dorsal spinal roots.

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32
Q

How many posterior spinal arteries are there?

What is their origin?

A

2

Vertebral arteries or from PICA

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33
Q

What are 3 important contributory arterial systems to the segmental supply of the spinal cord?

A

Deep cervical artery

Intercostal

Lumbar

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34
Q

What is the most important contributory artery to the anterior spinal artery?

A

Artery of Adamkiewicz/Great Medullary Artery (direct supply from the aorta).

Mostly on left.

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35
Q

What are the two watershed zones of the spinal cord supplied by the anterior spinal artery?

What is the clinical significance of this?

A

T4

L1

These are the most common areas to infarct in the compromise of anterior spinal arterial supply.

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36
Q

What is the watershed zone of the posterior spinal arteries?

A

T1-3.

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37
Q

Origin of AICA

A

Variable, arises from basilar or vetrebral

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38
Q

Structures supplied by AICA

A

Anteroinferior cerebellum

Lateral pons

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39
Q

Which artery supplies the middle ear?

Origin?

A

Labyrinthine artery

Basilar or from AICA

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40
Q

SCA supplies

A

Superior cerebellum.

Portion of midbrain.

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41
Q

Where does the internal carotid pierce dura mater to enter the subarachnoid space?

A

Medial to anterior clinoid process

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42
Q

Ophthalmic artery branches

DR MCLESSI

First and second last branches of the mnemonic are the terminal branches

A

Dorsal nasal artery

Retinal artery

Muscular artery

Cilliary arteres (long, short and anterior)

Lacrimal artery

Ethmoidal arteries (anterior and posterior)

Supraorbital artery

Supratrochlear artery

Internal palpebral artery

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43
Q

Which blood vessel is the most common site for Berry aneurysm?

A

AComm

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44
Q

C1 carotid

A

Cervical portion

From the carotid bifurcation to the carotid foramen of the skull base

No branches

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45
Q

C2 carotid

A

Petrous portion

From the carotid foramen to the posterior edge of the foramen lacerum in the carotid canal.

One branch:

Caroticotympanic artery

[vidian artery occasionally]

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46
Q

Branches of the second carotid segment

A

Petrous portion

Caroticotympanic and vidian

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47
Q

C3 carotid

A

Lacerum segment

Small portion where the ICA passes over the foramen lacerum

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48
Q

C4 carotid

A

Cavernous segment

From the foramen lacerum (petrolingual ligament) to the anterior clinoid process

Multiple branches including

Meningohypophyseal trunk

Inferolateral trunk.

Medial trunk or McConnell’s artery goes to the capsule of the pituitary gland.

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49
Q

Branches of the fourth segment of the carotid

A

Cavernous segment

Meningohypophyseal trunk

Inferolateral trunk

McConnel’s capsular artery

(small capsular arteries to the wall of the cavernous sinus)

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50
Q

Branches of the meningohypophyseal trunk

A

Tentorial artery (AKA Bernasconi and Cassinari artery)

Dorsal meningeal artery

Inferior hypophyseal artery

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51
Q

Bernasconi and Cassinari artery

A

Tentorial artery

Branch of the meningohypophyseal trunk (D)

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52
Q

McConnell’s artery

A

They arise from the medial wall of the cavernous ICA distal to both the meningohypophyseal trunk and the inferolateral trunk.

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53
Q

C5 carotid

A

Clinoid segment

Between the proximal and distal dural rings

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54
Q

Branches of the external carotid

A

Superior thyroid

Ascending pharyngeal

Lingual

Facial

Occipital

Posterior auricular

Maxillary

Superficial temporal

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55
Q

C6 carotid

A

Ophthalmic segment

From the distal dural ring to the PComm

Two important branches:

Ophthalmic

Superior hypophyseal

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56
Q

Important branches of the sixth segment of the internal carotid

A

Ophthalmic segment

Ophthalmic artery

Superior hypophyseal artery

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57
Q

C7 carotid

A

Communicating segment

From the PComm artery to the bifurcation of the ICA into the ACA and the MCA

Branches are

PComm

Anterior choroidal

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58
Q

Branches of the 7th segment of the carotid

A

PComm

Anterior choroidal

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59
Q

Classification of the ACA

A

Can be grossly divided into precommunicating and postcommunicating segments based on its relation to the AComm

Can also be divided into 5 segments

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60
Q

A1 ACA

A

From the bifurcation to the AComm

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61
Q

A2 ACA

A

From the AComm to the junction of the rostrum and genu of the corpus callosum

Recurrent artery of Heubner may arise from either the junction of A1/2 or from A1 or A2

A2 segment normally gives off the frontopolar and the orbitofrontal artery

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62
Q

A3 of the ACA

A

Travels around the genu of the corpus callosum and becomes A4 after turning sharply.

Highly variable branches including the callosomarginal which may divide into the anterior, middle and posterior internal frontal arteries. These 3 arteries may also arise directly from the A3 segment.

The pericallosal artery may also arise from the segment or be a direct continuation of the ACA

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63
Q

A4/5 segments of ACA

A

Run over the body of the corpus callosum

Separated from each other via a vertical line running over the callosal surface

A4 gives off the paralobular central artery.

A5 gives off superior and inferior internal parietal arteries.

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64
Q

M1 of the MCA

A

The sphenoidal or horizontal segment

From the origin of the MCA to the bifurcation into a superior and inferior trunk.

Lateral lenticulostriate arteries arise from this segment

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65
Q

M2 of the MCA

A

Insular segment

Runs in the depth of the Sylvian fissure from its bifurcation.

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66
Q

M3 of the MCA

A

Opercular segment

From the depths of the Sylvian fissure on its posterior segment to the surface

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67
Q

M4 of the MCA

A

Cortical segment

Starts at the surface of the Sylvian fissure and gives off multiple branches travelling to the cortical surfaces of the cerebral hemispheres.

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68
Q

V1 of the vertebral artery

A

Subclavian to C6 transverse foramina

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69
Q

V2 of the vertebral artery

A

Vertebral segment

From C6 to C2

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70
Q

V3 of the vertebral artery

A

Extradural segment, from C2 to the foramen magnum

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71
Q

V4 of the vertebral artery

A

Intradural segment

From its entry to the dura of the foramen magnum to its unification with the contralateral vertebral artery and formation of the basilar

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72
Q

Branches of basilar

A

AICA

Labyrinthine

Pontine

SCA

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73
Q

P1 of the PCA

A

Precommunicating

From the bifurcation of the basilar to the junction of the PComm

Gives off multiple perforators to the diencephalon and anterolateral midbrain.

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74
Q

P2 of the PCA

A

Ambient segment

From PComm to posterior edge of the midbrain.

Lateral posterior choroidal artery and thalamogeniculate arteries

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75
Q

P3 of PCA

A

Quadrigeminal segment

From the posterior edge of the midbrain to the calcarine anterior limit of the calcarine fissure.

Posterior temporal artery, Parieto-occipital and calcarine artery, Posterior pericallosal artery

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76
Q

Two main superficial veins of the cranium

A

Superior vein of Trolard

Inferior vein of Labbe

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77
Q

Vein of Trolard

A

Drains from Sylvian fissure to SSS

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78
Q

Vein of Labbe

A

Drains from Sylvian fissure to transverse sinus

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79
Q

What are the major deep veins

A

Internal cerebral vein

Vein of Galen

Basal vein of Rosenthal

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80
Q

Internal cerebral vein

A

Receives the thalamostriate vein at the foramen of Monro and the septal vein

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81
Q

Basal vein of Rosenthal

A

Drains the base of the brain from the anterior perforated substance to the internal cerebral vein

Joins to form the vein of Galen

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82
Q

Vein of Galen

A

Formed by the internal cerebral and basal vein of Rosenthal

Joins with ISS to form straight sinus

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83
Q

Function of BBB

A

Stabilises internal environment of CNS

Protects CNS from endogenous and exogenous toxins and bacteria

Maintains concentration of neurotransmitters

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84
Q

Types of capillaries

A

Continuous (tight)

Fenestrated

Sinusoidal

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85
Q

What are the special features of the endothelial cells of neurovascular capillaries

A

Tight junctions between cells

Demonstrate very low levels of transcellular vesicular transport

No fenestrations

P-glycoproteins (ATP dependent pumps that pump lipid-soluble toxins out of CNS)

Basement membrane (contains pericytes)

Astrocyte foot processes against BM release substances which stimulate endothelial cells to produce occludins and other factors that promote type junctions

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86
Q

What substances cannot cross BBB?

A

Plasma proteins or plasma protein-bound substances

Highly charged molecules/polar/water-soluble molecules

Toxic substances

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87
Q

Which substances can cross the BBB?

A

Small molecules

Non-polar/lipid soluble molecules

Specific facilitative transporters (e.g. for glucose)

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88
Q

Which glucose transporters are present in CNS capillaries?

A

GLUT-1

(independent of insulin)

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89
Q

Components of the blood-CSF barrier?

A

Fenestrated endothelial cells without tight junctions.

BM of endothelial cells

BM of ependymal cells

Specialised ependymal cells (choroidal epithelial cells) which possess tight junctions

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90
Q

Under which circumstances is BBB disrupted?

A

Physiological:

Circumventricular organs

Neonates

Pathological:

Trauma

Inflammation/infection

Irradiation

Neoplasm

Hypertensive encephalopathy

High altitude (hypoxia can damage BBB)

All cause vasogenic oedema

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91
Q

What is bounded superiorly by the anterior commissure and inferiorly by the optic chiasm?

A

Lamina terminalis of the third ventricle

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92
Q

What are the periventricular organs?

A

Sensory:

Vascular organ of lamina terminalis (OVLT)

Area postrema

Subfornical organ

Median eminence

Secretory:

Posterior pituitary

Subcommissural organ

Pineal gland

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93
Q

What is the embryological significance of the lamina terminalis?

A

Derives from cranial neuropore

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94
Q

What is the arrangement of capillary endothelial lining at the periventricular organs?

A

Fenestrated (except subcommissural)

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95
Q

Why is the BBB broken in the median eminence?

A

To allow carriage of regulatory peptides from hypothalamus to pituitary

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96
Q

Why is the BBB broken at the OVLT?

A

Senses presence of peptides in blood including AngII and IL-1

Contains osmoreceptors

Interacts with supra-optic nucleus promoting the release of ADH

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97
Q

Function of subfornical organ?

A

Contains neurones sensitive to AngII

Acts as thirst centre and centre for regulation of fluid balance.

Connected with OVLT

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98
Q

Why is BBB broken at pineal gland

A

To allow secretion of melatonin into blood

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99
Q

Function of subcommissural organ?

A

Not clearly established

No fenestrated capillaries

In other species secretes glycoproteins into the ventricular system to form Resiner’s fibres/threads which keep the system open. ?Aetiology of congenital cerebral aqueduct stenosis

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100
Q

Location of area postrema

A

Two centres

Lower portion of floor of fourth ventricle

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101
Q

Function of area postrema

A

Emetogenic substances

Connected with dorsal nucleus of vagus and nucleus of tractus solitarius which together are called the dorsal vagal triangle

Known as chemoreceptor trigger zone

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102
Q

At what point is the PCA joined by the PComm?

A

The lateral margin of the interpeduncular cistern.

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103
Q

Structures supplied by the PCA?

A

Posterior part of the cerebral hemispheres

Thalamus

Midbrain

Other deep structures including the choroid plexus and walls as lateral and third ventricles

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104
Q

P1 Segment of PCA

A

Precommunicating segments

Extends from the basilar bifurcation to the junction with the PCommA

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105
Q

What is meant by a fetal P1 configuration

A

In which the P1 has a smaller diameter than the PComA and the PCA arises predominantly from the carotid artery

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106
Q

In what proportion of hemispheres is a fetal PComm arrangement found?

A

1/3rd of hemispheres

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107
Q

Relationship of the oculomotor to PCommA

A

Passes below and slightly lateral to the PComA if a normal configuration is present.

If a fetal pattern is present, P1 is longer and the nerve courses beneath or medial to the communicating artery

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108
Q

What are the 4 constant branches of P1?

A

Thalamoperforating artery (enters the brain through the posterior perforated substance)

Medial posterior choroidal artery

Branch to quadrigeminal plate

Rami to the cerebral peduncle and mesencephalic tegmentum.

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109
Q

Extent of the P2 segment

A

Begins at the PCommA

Lies within the crural and ambient cisterns, terminating laterally to the posterior edge of the midbrain.

Divided into an anterior and posterior part

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110
Q

Anterior part of P2

A

P2A or crural/peduncular segment as it courses around the cerebral peduncle in the crural cistern

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111
Q

Posterior part of P2

A

P2P or ambient/lateral mesencephalic segment because it courses lateral to the midbrain in the ambient cistern

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112
Q

Passage of P2A

A

Begins at PCommA and courses between the cerebral peduncle and uncus that forms the medial and lateral walls of the crural cistern and inferior to the optic tract and basal vein that crosses the roof of the cistern to enter the proximal portion of the ambient cistern

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113
Q

Passage of P2P

A

Commences at the posterior edge of the cerebral peduncle at the junction of the crural and ambient cisterns.

Passes between the lateral midbrain and the parahippocampal and dentate gyri which form the medial and lateral wallls of the ambient cistern below the optic tract, basal vein and geniculate bodies.

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114
Q

P3 Segment

A

Quadrigeminal segment

Proceeds posteriorly from the posterior edge of the lateral surface of the midbrain and ambient cistern to reach the lateral part of the quadrigeminal cistern and ends at the anterior limit of the calcarine fissure.

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115
Q

What is the quadrigeminal point

A

The point where the PCAs from each side are nearest is referred to as the collicular or quadrigeminal point.

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116
Q

P4 Segment

A

Includes the cortical branches.

Begins at the anterior end of the calcarine sulcus

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117
Q

What are the 3 categories of PCA branches

A

Central perforating branches to the di and mesencephalon

Ventricular branches to the choroid plexus and walls of the lateral and third ventricles and adjacent structures

Cerebral branches to the cortex and splenium of the corpus callosum

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118
Q

Perforating branches of the PCA

A

Divided into direct and circumflex arteries

Direct:

Thalamoperforating arteries (P1)

Thalamogeniculate and peduncular perforating arteries (P2)

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119
Q

Circumflex arteries of the PCA

A

Encircle the brainstem for a variable distance before entering the diencephalon and mesencephalon and divided into long and short groups dependent on how far they course around the brainstem.

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120
Q

Through which transverse foramen of the cervical vertebra does the vertebral artery pass?

A

C1-6

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121
Q

How many segments of the vertebral artery are there?

A

4 segments

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122
Q

Extent of V1

A

Prevertebral.

From its origin at the subclavian artery to C6

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123
Q

Extent of V2

A

Vertebral segment

Runs within the transverse foramen from C6 to C2

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124
Q

Extent of V3

A

Extradural segment

From C2 to the foramen magnum

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125
Q

Extent of V4?

A

From the entry into the dura of the foramen magnum until its jucntion with the contralateral vertebral artery where it forms the basilar.

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126
Q

What are the collateral branches of the vertebral arteries?

A

Anterior meningeal artery

Posterior meningeal artery

Posterior spinal artery

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127
Q

Branches of the vertebral artery

A

ASA

PICA

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128
Q

Features of the anterior spinal artery?

A

Formed from two branches oiginating from each of the VAs prior to their union as the basilar artery.

Runs in the surface of the anterior median fissure of the spinal cord, supplies blood to the anterior 2/3rds.

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129
Q

Features of PICA

A

Supplies the posterolateral medulla, the fourthh ventricle and the posteroinferior cerebellar hemispheres

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130
Q

Level of termination of the basilar artery?

A

Interpeduncular cistern

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131
Q

Branches of the basilar

A

AICA

Labyrinthine

Pontine

SCA

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132
Q

Number of segments of PCA?

A

4 segments

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133
Q

Extent of P1

A

Pre-communicating segment

From the bifurcation of the basilar artery to the junction of PComm

Gives off multiple perforators to the thalamus, hypothalamus, subthalamus and the anterolateral segment of the midbrain.

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134
Q

Extent of P2

A

Ambient segment

From the junction of the PComm to the posterior edge of the midbrain.

Some of the PCA branches at this segment are the lateral posterior choroidal artery and thalamogeniculate arteries.

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135
Q

Extent of the P3 segment

A

Quadrigeminal segment

From the posterior edge of the midbrain to the anterior limit of the calcarine fissure.

The branches of this segment supply the posteroinferior temporal lobe (posterior temporal artery)

Occipital lobe (parieto-occipital artery and calcarine artery

And the posterior segment of the corpus callosum (posterior pericallosal artery)

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136
Q

Extent of P4 segment

A

Terminal segment

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137
Q

Anatomy of Alexia without Agraphia

A

Cerebral hemispheric infarction

Left occipital region plus splenium of the corpus callosum.

Due to infarction of Callosal branches

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138
Q

Pure word blindness, can write but not read

A

Alexia without agraphia

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139
Q

Signs and symptoms of alexia without agraphia

A

Can write but not read

May have contralateral homonymous hemianopia

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140
Q

Balint Syndrome

A

Oculomotor ataxia

Bilateral loss of voluntary but not reflex eye movements

Bilateral optic ataxia- poor visual-motor coordination

Asimultagnosia- inability to understand visual objects

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141
Q

Anatomy of Balint syndrome

A

Bilateral parietal occpital lobe infarct due to bilateral PCA stroke

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142
Q

Claude Syndrome

A

Ipsilateral CN3

Contralateral ataxia of arm and leg.

Marked ataxia differentiates from Benedikt’s

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143
Q

Anatomy of Claude syndrome

A

Contralateral ataxia due to infarction of midbrain tegmentum secondary to PCA occlusion.

May also have ipsilateral oculomotor palsy with contralateral tremor and ataxia

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144
Q

Anton Syndrome

A

Cortical blindness

Bilateral visual loss

Unawareness or denial of blindness

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145
Q

Anatomy of Anton syndrome

A

Bilateral PCA occlusion or top of basilar occlusion

Due to bilateral occipital lobe involvement

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146
Q

Unilateral Occpital PCA stroke

A

Conralateral homonymous heminaopia with macular sparing

Due to infarction of occipital and infero-medial temporal lobes

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147
Q

Dejerine Roussy Syndrome

A

Thalamic pain syndrome

Due to thalamoperforator branch infarction

Causes hemisensory loss- all modalities then development of intractable hemi-body pain

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148
Q

Weber Syndrome

A

Basal midbrain stroke

Contralateral weakness of arm and leg due to corticospinal tract involvelent
Ipsilateral CN3 palsy

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149
Q

Benedikt syndrome

A

Paramedian midbrain syndrome

Ipsilateral CN3 palsy

Cerebellar ataxia with choreoathetotic movements (red nucleus)

May involve contralateral hemiparesis due to involvement of corticospinal tract.

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150
Q

Artery of Davidoff and Scheter

A

The artery of Davidoff and Schechter (ADS) is a dural branch that arises from the posterior cerebral artery and supplies the falcotentorial junction. It is usually not identified on angiography except when enlarged in the setting of dural AVFs, meningiomas, or, rarely, cerebellar tumours

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151
Q

Normal CBF

A

50ml/100g/min

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152
Q

Vertebral artery dominance

A

Left side 50%

Right side 25%

Non-dominance 25%

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153
Q

The left vertebral artery arises from the aorta in what proportion of patients?

A

5%

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154
Q

What proportion of the population have a hypoplastic vertebral artery?

A

40%

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155
Q

Structures supplied by superior thyroid artery

A

Larynx and upper thyroid

Anastomoses with the thyrocervical trunk

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156
Q

Structures supplied by and anastomoses:

Ascending pharyngeal

A

Nasopharynx, oropharynx and middle ear

CNs IX-XI

Meninges

Vertebral artery branches

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157
Q

Structures supplied by and anastomoses:

Lingual artery

A

Tongue and floor of mouth

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158
Q

Structures supplied by and anastomoses:

Facial artery

A

Face, palate, lips

Angular branch of the facial artery anastomoses with the orbital branch of the ophthalmic

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159
Q

Structures supplied by and anastomoses:

Occipital artery

A

Posterior scalp, upper cervical musculature, posterior fossa and meninges

Anastomoses with the vertebral artery

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160
Q

Structures supplied by and anastomoses:

Posterior auricular artery

A

Pinna, EAC, scalp

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161
Q

Structures supplied by and anastomoses:

Superficial temporal

A

Scalp and ear

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162
Q

Structures supplied by and anastomoses:

Maxillary

A

Deep face

Gives off MMA and accessory meningeal

Anastomoses with inferolateral trunk, ophthalmic and petrous carotid via ethmoidal and vidian branches

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163
Q

Subsegmentation of the intracavernous ICA

A

Ascending portion (entrance into the cranium to the genu)

Posterior genu (between C5 and C3 segments)

Horizontal portion (between the genu)

Anterior genu

Remainder of intracavernous ICA segment

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164
Q

Location of the cervical ICA

A

Larger than ECA

Located in the lateral pharyngeal space

Initially posterolateral to the ECA but becomes medial to enter the carotid canal anteromedial to the IJV

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165
Q

Location of the petrous ICA

A

Enters the caroid canal of petrous temporal bone

Lies behind the eustachian tube

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166
Q

Segments of petrous ICA

A

Vertical sgment (10mm)

Horiztonal (20mm), exits the petrous apex superior to the foramen filled lacerum

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167
Q

Caroticotympanic artery

A

Embryonic hyoid artery remnant

Arises near the genu of the petrous ICA passes superiorly

When aberrant can cause retrotympanic pulsatile mass

Anastomoses with inferior tympanic artery (ECA)

Supplies middle and inner ear

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168
Q

MHT branches

A

Italian artery (tentorial)

Inferior hypophyseal

Dorsal meningeal

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169
Q

Structures supplied by:

Tentorial artery

A

Tentorium

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170
Q

Structures supplied by:

Inferior hypophyseal artery

A

Neurohypophysis

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171
Q

Structures supplied by:

Dorsal meningeal artery

A

CN VI and clivus

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172
Q

Structures supplied by:

Inferolateral trunk

A

Inferolateral cavernous sinus wall, tentorium, CN III, IV, VI, V ganglion

Anastomoses with the maxillary artery and MMA

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173
Q

Medial trunk of cavernous sinus

A

Present in 28% of the population

Anterior capsular artery- medially over sellar roof

Inferior capsular artery- inferomedially to the sellar floor

Supplies anterior and inferior pituitary

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174
Q

Ophthalmic artery branches

DR MCLESSI

A

D: dorsal nasal artery

R: (central) retinal artery

M: muscular artery

C: ciliary arteries (long, short and anterior)

L: lacrimal artery

E: ethmoidal arteries (anterior and posterior)

S: supraorbital artery

S: supratrochlear artery (frontal artery)

I: internal palpebral artery

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175
Q

Aneurysms of ophthalmic artery

A

Arise from the superior wall of the ICA distal to the OA origin, project superiorly and may abut the CN II

176
Q

Structures supplied by the superior hypophyseal artery

A

Adenohypophysis and the infundibulum

Tuber cinereum

Inferior surface of the optic chiasm and CN II

177
Q

Course of the SHA

A

Arises from the posteromedial ophthalmic ICA beneath CN II

178
Q

SHA aneurysms

A

Project inferiorly and medially

179
Q

Course of PCommA

A

Arises from the posterior wall of the ICA and passes posterolaterally above CN III to join the P1 segment of PCA

180
Q

Structures supplied by PComm

A

Posterior hypothalamus

Anterior thalamus

STN

Posterior limb of internal capsule via seven perforators that are equally distributed along the vessel length and course superomedially to their targets

181
Q

PComm Aneurysms

A

Normally arise from the posterior wall of the ICA immediately distal to the PComm origin and point towards CNIII

PComm is typically inferomedial to the aneurysm and the anterior choroidal artery is superior lateral

182
Q

What proportion of population has variant PComm?

Categories of PComm variation

A

50%

Absent or hypoplastic

Fetal

Infundibulum

183
Q

What proportion of the population have an absent or hypoplastic PComm?

A

30%

184
Q

What proportion of population have fetal PComm

A

20%

(PComm A same diameter as P1)

185
Q

PComm infundibulum

A

Funnel-shaped dilatation of the PComm <2mm

186
Q
A

PComm arising from dome of a pyramidal dilatation

Differentiated from aneurysm does which does not come off tip

187
Q

Structures supplied by the medial proximal striate branches of A1

A

1-12 perforators

Optic nerve and chiasm

Anterior hypothalamus

Septum pellucidum

Anterior commissure

Pillars of the fornix and the anteroinferior striatum

NB Medial DISTAL lenticulostriate artery= recurrent artery of Heubner

188
Q

AComm perforators

A

2 or more arise from the AComm to supply:

Infundibulum

Chiasm

Subcallosal area

Preoptic hypothalamus

Include the subcallosal artery and medial artery of the corpus callosum

189
Q

AComm aneurysms

A

Usually arise at the point where the dominant A1 bifurcates and point towards the contralateral side

190
Q

Branches of A2

A

Heubner (A1)

Orbitofrontal artery

Frontopolar artery

Anterior internal frontal artery

191
Q

Branches of A3

A

Callosomarginal artery

Pericallosal artery

Middle internal frontal artery

Posterior internal frontal artery

Paracentral artery

Superior parietal artery

Inferior parietal artery

192
Q

What proportion of the population have an MCA bifurcation

A

50%

193
Q

What proportion of the population have an MCA trifurcation

A

25%

194
Q

Branches of M1

A

Uncal artery

Temporopolar artery

Anterior temporal artery

Lateral lenticulostriate arteries

195
Q

Structures supplied by the callosomarginal artery

A

Cingulate gyrus and paracentral lobule

196
Q

Second most common ACA site for aneurysms?

A

Junction of the pericallosal artery with callosomarginal

Aneurysms usually point distally

197
Q

Structures supplied by pericallosal artery

A

Medial parietal cortex and precuneus

198
Q

Structures supplied by middle internal frontal artery

A

Medial frontal cortex

199
Q

Structures supplied by posterior internal frontal artery

A

Medial posterior frontal cortex

200
Q

Structures supplied by paracentral artery?

A

Medial cortex around the central sulcus

201
Q

Structures supplied by superior parietal artery

A

Medial superior parietal lobe

202
Q

Structures supplied by inferior parietal artery

A

Medial inferior parietal lobe

203
Q

Features of the uncal artery

A

More frequently arises from the distal ICA than proximal M1

Supplies uncus and underlying white matter

204
Q

Structures supplied by temporopolar artery?

A

Anterior pole of superior, middle and inferior temporal gyri

205
Q

Structures supplied by anterior temporal artery?

A

Anterior pole of the superior, middle and inferior temporal gyri

206
Q

Structures supplied by lateral lenticulostriate arteries

A

2-15 perforators from M1

Substantia innominata

Anterior commissure

Putamen

Globus pallidus

Superior half of internal capsule

Head and body of caudate

207
Q

Branches of the superior trunk of M2

A

Orbitofrontal branch

Prefrontal branch

Precentral branch

Central branch

Anterior parietal branch

208
Q

Structures supplied by

Orbitofrontal branch of the superior trunk of M2

A

Orbital portion of middle and inferior frontal gyri and the inferior pars orbitalis

209
Q

Structures supplied by

Prefrontal branch

A

Branch of superior M2 trunk

Superior pars orbitalis

Pars triangularis

Anterior pars opercularis

Most of the middle frontal gyrus

210
Q

Structures supplied by

Precentral branch

A

Posterior pars opercularis

Middle frontal gyrus and inferior and middle portions of the precentral gyrus

211
Q

Structures supplied by

Central branch

A

Superior trunk M2

Superior postcentral gyrus, upper central sulcus, anterior part of the inferior parietal lobule and the anteroinferior region of the superior parietal lobule

212
Q

Structures supplied by

Anterior parietal branch

A

M2 superior trunk

Superior parietal lobule

213
Q

Branches of the inferior trunk of M2

A

Posterior parietal branch

Angular branch

Temporo-occipital branch

Posterotemporal branch

Middle temporal branch

214
Q

Structures supplied by the posterior parietal branch of inferior trunk of M2

A

Posterosuperior and inferior parietal lobule and inferior supramarginal gyrus

215
Q

Structures supplied by angular branch of the inferior M2 trunk

A

Posterior aspect of the superior temporal gyrus

Portions of the supramarginal and angular gyri and the superior aspect of the lateral occipital gyrus

216
Q

What is the largest cortical branch of the MCA?

A

Angular branch

217
Q

Structures supplied by the temporo-occipital branch of inferior M2 trunk

A

Posterior half of the superior temporal gyrus, the posterior extreme of the middle and inferior temporal gyri

Inferior lateral occipital gyrus

218
Q

Structures supplied by the posterotemporal branch of inferior M2 trunk

A

Middle and posterior portion of the superior temporal gyrus

Posterior 1/3 of middle temporal gyrus

Posterior extreme of the inferior temporal gyrus

219
Q

Structures supplied by the middle temporal branch of inferior M2 trunk

A

Superior temporal gyrus near the level of the pars trianagularis and pars opercularis

Central part of the middle temporal gyrus

Middle and posterior parts of the inferior temporal gyrus

220
Q

P1 branches

A

Posterior thalamoperforator

Medial posterior choroidal arteries

Meningeal branches

221
Q

Passage of posterior thalamoperforators

A

From basilar and P1

Pass through the posterior perforated substance behind the mamillary bodies to supply the thalamus, hypothalamus, subthalamus and midbrain

222
Q

Structures supplied by the medial posterior choroidal arteries

A

Travels anteromedially along the roof of the third ventricle

Supplies the midbrain tectum, posterior thalamus, pineal gland and tela choroidea of the third ventricle

223
Q

Structures supplied by meningeal branches of P1

A

Tentorium and falx

224
Q

Branches of P2 segment

A

Lateral posterior choroidal

Thalamogeniculate

Cortical branches

225
Q

Lateral posterior choroidal artery

A

Main branch of P2

Courses over the pulvinar and through the choroidal fissure

Supplies the posterior portion of the thalamus and choroid plexus (temporal horn and atrium)

226
Q

Thalamogeniculate branches

A

Supply MGN, LGN, pulvinar

Superior colliculus

Crus cerebri

227
Q

Structures supplied by cortical branches of P2

A

Inferior temporal artery

228
Q

P3 branches

A

Posterior temporal artery

Internal occipital artery

Parieto-occipital artery

Calcarine artery

Posterior pericallosal artery

229
Q

Posterior temporal artery

A

P3 branch

Posterior temporal lobe

Occipitotemporal and lingual gyri

Anterior temporal artery branch travels to the inferior temporal lobe to supply the inferior cortex

Anastomoses with MCA

230
Q

Parieto-occipital artery

A

P3 branch

Located in the parieto-occipital sulcus

Supplies the posterior 1/3rd of the medial hemispheres

Cuneus

Precuneus

Superior occipital gyrus and precentral and superior parietal lobules

Anastomoses with ACA

231
Q

Calcarine artery

A

P3

Located in calcarine sulcus

Supplies the occipital pole and visual cortex

232
Q

Posterior pericallosal artery

A

P3

Supplies splenium of the corpus callosum

233
Q

Origin of Anterior choroidal artery

A

Arises from the posteromedial surface of the ICA immediately distal to the origin of the PCommA

234
Q

Course of the anterior choroidal

A

Cisternal (ambient)

and

Intraventricular segments

Enters the choroidal fissure at the plexal point- temporal horn of the lateral ventricle

235
Q

Where does the anterior choroidal artery enter the lateral ventricle?

A

At the plexal point (AKA inferior choroidal point)

236
Q

Structures supplied by the anterior choroidal artery

A

Via perforators

Choroid of the lateral ventricles (esp temporal horn)

Hippocampus, amygdala, uncus

GP, caudate tail, putamen

VL nucleus of the thalamus

Posterior limb of the internal capsule

Inferior optic chiasm, optic tract, LGN, optic radiation

237
Q

Historical significance of anterior choroidal artery

A

Previously sacrificed to treat Parkinson’s disease.

Likely reduced tremor due to reduction in blood supply to the VL thalamus

238
Q

What proportion of individuals have a complete CoW

A

25%

239
Q

Categories of penetrating arteries of the CoW

A

Anteromedial

Anterolateral

Posteromedial

Posterolateral

240
Q

Anteromedial perforators

A

Arise from ACA and AComm including RAH

Enter the anterior perforated substance to supply anterior hypothalamus, preoptic nucleus and supraoptic nucleus

241
Q

Posteromedial perforators

A

Arise from proximal PCA and PCommA

Supply the hypophysis, infundibulum and tuberal hypothalamus

Thalamoperforating arteries which supply the mammillary bodies, subthalamus and midbrain

242
Q

Anterolateral perforators

A

Striate arteries from proximal MCA and recurrent artery of Heubner

Enter the anterior perforated substance

Supply the head of caudate, lateral GP, putamen, claustrum, IC and EC

243
Q

Posterolateral perforators

A

Arise from PCA (thalamogeniculate arteries)

Supply caudal thalamus (geniculate bodies, pulvinar, lateral nucleus and lateral ventral nucleus)

244
Q

In what proportion of patients does the vertebral artery enter the foramen transversarium at C6?

A

90%

245
Q

Anastomoses of the vertebral

A

ECA

Thyrocervical

Costocervical

246
Q

Branches of the vertebral

A

Extracranial:

  1. Segmental spinal branches
  2. Muscular branch
  3. Meningeal branch

Anterior and posterior spinal arteries

PICA

247
Q

Muscular branch of vertebral artery

A

Anastomoses with muscular branch of ECA (ascending pharyngeal, thyrocervical and costocervical)

248
Q

Meningeal branches of vertebral

A

Anterior meningeal branch-> FM dura

Posterior meningeal branch-> falx and post fossa dura

249
Q

Blood supply of the falx cerebelli

2 vertebral, 2 ECA

A

Posterior meningeal branches

PICA

Occipital

Ascending pharyngeal

250
Q

Structures supplied by posterior spinal arteries at the cervicomedullary junction

A

Gracile and cuneate fasciculi

Inferior cerebellar peduncle

251
Q

Structures supplied by the anterior spinal artery at the level of the cervicomedullary junction?

A

Pyramid

Medial lemniscus

MLF

Olive

Vagal and hypoglossal nuclei

252
Q

What proportion of vertebral arteries terminate as the PICA

A

1-25%

253
Q

Structures supplied by PICA

A

Choroid of fourth

Posterior lateral medulla

Tonsils

Vermis

Posteroinferior cerebellar hemispheres

254
Q

Relation of AICA to CNs

A

Crosses CN VI and the cerebellopontine angle cistern to the IAC

Passes anterior and inferior to CNs VII and VIII

255
Q

Branches of AICA

A

Internal auditory artery

Recurrent perforating artery

Subarcuate artery

256
Q

Blood supply:

Striatum

A

Mainly lenticulostriate arteries of MCA

Rostrally- recurrent artery of Heubner

Caudally: Ant Choroidal

257
Q

Blood supply:

IC

A

Anterior limb: ACA (RAH, MCA lateral lenticulostriate)

Genu: ICA perforators, MCA lenticulostiate

Posterior limb: Ant choroidal and PComm

258
Q

Blood supply:

Thalamus

A

PCA by way of perforators: thalamoperforators, thalmogeniculate arteries, medial posterior choroidal arteries

Rostrally: PComm A (anterior thalamoperforating arteries)

[and basilar bifurcation perforators)

259
Q

Diploic veins

A

Communicate with the scalp, meningeal veins and dural sinuses

260
Q

Meningeal veins

A

Epidural vessels of the dura which follow meningeal arteries and drain into dural sinuses or into the extracranial pterygoid venous plexus

261
Q

What proportion of people have a dominant right transverse sinus

A

60%

262
Q

ISS drains predominantly into?

A

Left transverse sinus

263
Q
A

Venous phase DSA

  1. Septal vein.
  2. Anterior caudate vein.
  3. Terminal vein.
  4. Thalamostriate vein.
  5. Atrial vein.
  6. Basal vein of Rosenthal.
  7. Vein of Galen.
  8. Internal cerebral vein.
  9. Venous angle.
264
Q

Superficial middle cerebral veins

A

Course along sylvian fissure

Drain into cavernous sinus or superior Trolard (Top) or Labbe (lower)

265
Q

Vein of Trolard

A

Drains from Sylvian fissure to SSS

266
Q

Vein of Labbe

A

Drains from Sylvian fissure to transverse sinus

267
Q

Internal cerebral veins

Location

A

Tela choroidea in the roof of the third ventricle

Extend from the foramen of Monro, over the thalamus and posteriorly to the quadrigeminal cistern where they unite to form the vein of Galen

268
Q

Formation of the internal cerebral veins

A

Formed by the union of the:

Thalamostriate

Choroidal

Septal

Epithalamic

Lateral ventricular

269
Q

Basal vein of Rosenthal

A

Drains the anterior and medial temporal lobe

Passes posterosuperiorly through the ambient cistern

Joins the internal cerebral vein to form the vein of Galen

270
Q

Vein of Galen formation

A

Receives both internal cerebral veins

Basal veins of Rosenthal

Occipital veins

Posterior callosal vein

Travels under the splenium and merges with the inferior sagittal sinus to form the straight sinus

271
Q

What are the ICA-ECA anastomoses?

A

Ascending pharyngeal-> VA

Ascending pharyngeal -> ICA via petrous and cavernous branches

Facial artery-> ICA via the angular branch of facial artery to orbital branch of ophthalmic

Occipital artery-> vertebral

Posterior auricular artery-> ICA via the stylomastoid artery

Maxillary artery-> ICA

272
Q

What are the maxillary artery to ICA anastomoses?

A

MMA to ethmoidal branch of ophthalmic

Temporal branches to ophthalmic

Infraorbital artery to ophthalmic

Artery of foramen rotundum to ILT

Accessory meningeal artery to ILT

Vidian artery to petrous ICA

Pharyngeal artery to cavernous ICA

MMA to primitive hyoid branch of the ICA

273
Q

Primitive hyoid branch of the ICA

A

Known as persistent stapedial artery

When present, the foramen spinosum is small or absent with an enlarged geniculate fossa

274
Q

What are the persistent fetal carotid-basilar and carotid-vertebral anastomoses?

A

Persistent trigeminal

Persistent acoustic

Persistent hypoglossal

Proatlantal intersegmental

275
Q

Rate of primitive trigeminal artery persistence

A

0.5% of angiograms

276
Q

Connections of primitive trigeminal artery

A

Connects cavernous ICA with embryonic dorsal longitudinal neural arteries

Arises from ICA just proximal to the cavernous sinus meningohypophyseal trunk

Curves medially to join the basilar between the SCA and AIC

277
Q

Associations of primitive trigeminal artery

A

Associated with hypoplastic PCommA and basilar and vertebral arteries proximal to anastomosis

Increased frequency of AVMs and aneurysms (25%)

278
Q

Connections of the persistent otic artery

A

Connects petrous ICA via internal auditory meatus to the basilar artery

Connects petrous ICA with embryonic dorsal longitudinal neural arteries

Very rare

279
Q

Which is the first fetal carotid-basilar communication to involute?

A

Otic

280
Q

What is the second most frequent persistent fetal circulation?

A

Primitive hypoglossal

281
Q

Rate of persistent primitive hypoglossal

A

0.3%

282
Q

Connections of primitive hypoglossal?

A

Connects cervical ICA with embryonic dorsal longitudinal arteries

Arises from the cervical ICA and connects to the basilar artery through the hypoglossal canal

283
Q

Associations with persistent hypoglossal arteries

A

Typically bilateral hypoplastic vertebral arteries thus this may be the main supply to the brain stem and cerebellum

284
Q

Proatlantal intersegmental artery

A

Connects ECA or cervical ICA with embryonic dorsal longitudinal neural arteries

Suboccipital anastomosis between cervical ICA and vertebral artery

Courses between the arch of C1 and the occiput

285
Q

Features of spinal radicular ateries

A

Derived from segmental vessels from the aorta which include the ascending cervical, deep cervical, intercostal, lumbar and sacral arteries

Pass through the intervertebral foramina to divide into anterior and posterior radicular arteries

286
Q

What happens to the anterior and posterior divisions of the spinal segmental arteries?

A

Anterior ramus of the segmental artery supplies the cord whilst the posterior ramus supplies the DRG and nerve roots via anterior and posterior radicular branches.

287
Q

Where does the artery of Adamkiewicz arise?

A

75% from T9-12

80% arise from the left

288
Q

Outline the blood supply to spinal cord segments

A

In each segment, the anterior spinal artery gives off several sulcal arteries that course posteriorly in the anterior median fissure.

Typically each artery enters one half of the SC to supply the anterior, base of posterior and anterior and lateral funiculi (2/3rds total) in that half

Paired posterior spinal arteries provide supply to the posterior 1/3rd including the posterior horn and funiculus

All three spinal arteries contribute numerous anastomosing vasocorona on the pial surface which in turn send branches to the peripheries.

289
Q

Posterior spinal artery supplies

A

Posterior one-third of the spinal cord

290
Q

Anterior spinal artery

A

Supplies anterior two-thirds of the SC

Joint at the medulla to enter the anterior median fissure as a single artery (anterior median spinal artery)

291
Q

Anterior radicular spinal arteries

A

2-17 arteries: cervical 6, thoracic 2-4, lumbar 1-2

Artery of Adamkiewicz

292
Q

Posterior radicular arteries

A

10-23 arteries

Divide at the posterolateral spinal cord surface and joins the paired posterior spinal arteries

293
Q

Posterior arterial system of the spinal cord

A

Paired posterior spinal arteries form a leptomeningeal peirmedullary network that anastomoses with the anterior system, most prominently at the conus where the anastomotic loop is located

Blood from the posterior medullary arteries flows centripetally in the perforating branches from the leptomeningeal system to the posterior columns and horns

294
Q

Anterior arterial system of the spine

A

Single midline artery that feeds into the anterior medullary artery in the anterior median fissure

Flows centrifugally via penetrating branches to the anterior and intermediate gray and via pial radial network to anterior and lateral WM

295
Q

Blood supply of cervical SC

A

Vertebral artery

PICA

Ascending cervical artery (thyrocervical trunk)

Deep cervical (costocervical)

296
Q

Blood supply of the thoracic SC

A

Thyrocervical and costocervical trunk

Intercostal artery (T3-11)

Subcostal artery (T12)

297
Q

Bloody supply to the lumbar SC

A

Lumbar artery (aorta L4-5)

298
Q

Blood supply to sacral SC

A

Lateral sacral artery (IIA) supplies sacral neural elements

Middle sacral artery

The aorta and iliac arteries send branches to the thoracolumbar spine

299
Q

Where is the SC most vulnerable to ischaemia?

A

At transitional regions where the arterial supply is derived from more than one source

T1-4

and

L1

Also vulnerable are areas between the anterior and posterior medullary arteries (between the intermiedate and dorsal horns and lateral and posterior fasciculi)

300
Q

Describe the venous drainage of the SC

A

Highly variable

Both anterior and posterior spinal veins lie adjacent to the spinal arteries which eventually drain into the intervertebral veins exiting the SC via intervertebral foramina

Anterior and posterior radicular vein

301
Q

Rhotons microsurgical segments of the supraclinoidal ICA

A

Ophthalmic segment

Communicating segment

Choroidal segment

302
Q

Anterior falx artery

A

Arises from the anterior ethmoidal branch of the ophthalmic artery and perforates the cribriform plate

Ascending in the falx parallel to the inner table of the skull

303
Q

Endoscopic landmarks for ethmoidal arteries

A

AEA passes through foramen 24mm posterior to anterior lacrimal ridge

PEA 12mm from anterior foramen

Optic canal 6mm posterior to the PEA

304
Q

In what proportion is the CoW intact?

A

18%

305
Q

Routes for venous drainage of cavernous sinus dAVFs

A

6 routes

SOV + IOV-> ocular symptoms

Inferior petrosal sinus-> basilar/ptyergoid plexus-> bruit and CN deficit

Superior petrosal sinus-> bruit

Sphenoparietal sinus-> superficial middle vein and cortical reflux with haemorrhage

Cerebellar drainage into petrous vein -> ataxia and haemorrhage

Deep drainage into middle cerebral and uncal vein-> haemorrhage

306
Q
A

Persistent hypoglossal artery

307
Q

What is the venous complex that surrounds the petrous segment of the ICA/

A

ICA venous plexus of Rektorzik

It is believed that the plexus serves to dampen arterial pulsations of the carotid artery, thereby reducing osseous transmission of sound to the cochlea

The plexus appears thickest between the carotid and the point closest to the cochlea, supporting this hypothesis

308
Q

Gibo classification of Carotid

A

C1-4

Cervical

Petrous

Cavernous

Supraclinoid

309
Q

Median prosencephalic vein of Markowski

A

A precursor to the vein of Galen

Before birth, its anterior portion regresses with the formation of the internal cerebral veins and its posterior portion persists as the vein of Galen

310
Q

Veins of Breschet

A

Diploic intraosseous veins

311
Q

Sinus of Breschet

A

Sphenoparietal venous sinus

312
Q

Vein of Vesalius

A

Sphenoidal emissary foramen gives passage to a small vein (vein of Vesalius) that connects the pterygoid plexus with the cavernous sinus. The importance of this passage lies in the fact that an infected thrombus from an extracranial source may reach the cavernous sinus

313
Q

Petro-occipital vein of Trolard

A

The inferior petro-occipital vein is located immediately inferior to the petro-occipital suture and provides a communication between the internal carotid artery venous plexus of Rektorzik, or less commonly the cavernous sinus, anteromedially and the jugular bulb, or less commonly the inferior petrosal sinus, posterolaterally

314
Q

Hypoglossal plexus of Trolard

A

The venous plexus of hypoglossal canal ( also known as plexus venosus canalis nervi hypoglossi (TA), circellus venosus hypoglossi and rete canalis hypoglossi– is a small venous plexus around the hypoglossal nerve that connects with the occipital sinus, the inferior petrosal sinus and the internal jugular vein.

315
Q

Vein of Dandy

A

Superior petrosal vein

usually formed by the convergence of multiple tributaries to form a single large vein that empties into the superior petrosal sinus.

316
Q
A
317
Q
A
318
Q

Superior M2 syndrome

A

Contralateral paralysis of face and arm

Contralateral sensory loss

Expressive dysphasia

319
Q

Inferior M2 syndrome

A

Contralateral HH

Receptive dysphasia

Impaired 2 point discrimination

320
Q

Artery of Salmon

A

A muscular branch from the third segment of the vertebral artery in the suboccipital triangle

Supplies blood to the suboccipital muscles

Found in 48%

(A)

321
Q

Artery of Wollschlaeger and Wollschlaeger

A

Branch of the superior cerebellar artery and becomes enlarged and elongated in vascular tumours and tentorial vascular malformations

(B)

322
Q

Which vessel is C?

A

Artery of Davidoff/Schecter

323
Q

Arteria termatica of Wilder

A

Formation of one artery from the fusion of A2, AKA azygos artery of the pericallosal artery

F

324
Q

Etymology azygos

A

Zygos means yoked or paired

i.e. unpaired

325
Q

Structures A-G

A

A- Meningohypophyseal trunk

B- Lateral tentorial artery

C- Marginal tentorial artery of Bernasconi-Cassinari

D- Inferior hypophyseal artery

E- Hypophyseal branches

F- Inferior clival branch

326
Q

Structures H-P

A

H- Lateral branch of lateral clival

I- medial branch of medial clival artery

J- jugular branches of ascending pharyngeal

K- Clival branches of Ascending pharyngeal

L- Petrosquamosal branches

M- foramen lacerum branch of the middle meningeal artery

O- Occipital artery

P- basilar.

327
Q

Which vessel runs alongside superior petrosal sinus

A

Lateral branch of lateral clival artery

328
Q

Which vessel runs alongside inferior petrosal sinus

A

Medial branch of lateral clival artery

329
Q

MHT on MR/CT or angio

A

Discernible MHT usually means some kind of pathology

Would not normally see on 1.5T

If MHT visible, consider proceeding to DSA ?dAVF if no other cause identified,

330
Q

What is denoted by the arrow

A

On MR T1 post contrast there is a hyperintense petroclival homogenously enhancing extra-axial lesion- likely meningioma

The arrow demonstrates the pathologically hypertrophied MHT branch supplying tumour.

331
Q
A

Red- inferior hypophyseal

White- pituitary blush

Purple- marginal tentorial

Blue- ILT

332
Q
A

Large vessel traversing pituitary fossa= primitive maxillary artery which arise in the context of carotid agenesis involving petrous segment

Can be reconstituted via contralateral through primitive maxillary anastomosis (fetal inferior hypophyseal arteries)

333
Q

Vascular territory

A

PICA

334
Q

Vascular territory

A

AICA

335
Q

Vascular territory

A

SCA

336
Q

Vascular territory

A
337
Q
A
338
Q
A
339
Q

Vascular territory

A
340
Q
A
341
Q
A
342
Q
A
343
Q
A
344
Q
A
345
Q
A
346
Q
A
347
Q
A
348
Q
A
349
Q
A
350
Q
A
351
Q
A
352
Q
A
353
Q
A
354
Q
A
355
Q
A
356
Q

Sylvian point

A

Most posterior M2 branch

Marks anterior margin of atrium

357
Q

Inferior choroidal point

A

Location where anterior choroidal enters the temporal horn of the lateral ventricle (posterior to the posterior aspect of uncus)

358
Q

In which medial temporal lobe sulcus does the anterior choroidal artery run?

A

Arises medial to semilunar gyrus and runs in semiannular sulcus before entering the temporal horn of lateral ventricle at the inferior choroidal point

359
Q

Relationship of SCA to 3,4,5

A

Runs below 3 + 4 and above 5

It may have two trunks- superior and inferior

360
Q

Maxillary artery anatomy

Overview

A

Origin behind the neck of the mandible

Divided into three portions by relation to lateral pterygoid

First- mandibular (posterior to lateral pterygoid, 5 branches)

Second- pterygoid/muscular (within lateral pterygoid, 5 branches)

Third- pterygopalatine (anterior to lateral pterygoid, 6 including terminal branch)

361
Q

Maxillary artery branches

First part

A

Mandibular

Deep auricular- squamotympanic fissure

Anterior tympanic artery- squamotympanic fissure

MMA- foramen spinosum

Accessory meningeal artery- foramen ovale

Inferior alveolar artery (artery to mylohyoid)- mandibular foramen

362
Q

Maxillary artery branches

Second part

A

Muscular/pterygoid part

Anterior, middle and posterior deep temporal branches

Pterygoid

Masseteric

Buccinator

363
Q

Maxillary artery branches

Third part

A

Pterygopalatine

Posterior superior alveolar artery

Infraorbital artery (infraorbital fissure)

Artery of pterygoid canal

Pharyngeal artery (palatovaginal canal)

Greater palatine artery

Sphenopalatine artery (sphenopalatine foramen)

364
Q

FV=

Tranmsmit

A

FV= foramen vesalius

Transmits sphenoidal emmissary veins (vein of Vesalius) from pterygoid plexus to cavernous sinus.

365
Q

Components of Rhoton’s neurovascular complex

A

Brainstem

Cerebellar pedcunles

Fissures

Arteries

Cerebellar surfaces

366
Q

Components of Rhoton’s neurovascular complex

Fissures between brainstem and cerebellum

A

Cerebellomesencephalic

Cerebellopontine

Cerebellomedullary

367
Q

Components of Rhoton’s neurovascular complex

Cerebellar surfaces

A

Tentorial

Petrosal

Suboccipital

368
Q

Upper neurovascular complex

A

SCA

Midbrain

Cerebellomesencephalic fissure

Superior cerebellar peducnle

Tentorial cerebellar surface

III, IV, V

369
Q

Relationship of SCA to upper neurovascular complex

A

SCA arises in front of the midbrain

Passes below 3,4 and above 5

Reaches cerebellomesencephalic fissure where it runs over the superior peduncle and supplies tentorial surface of cerebellum

370
Q

Middle neurovascular complex

A

AICA

Pons

Middle cerebellar peduncle

Cerebellopontine fissure

Petrosal cerebellar surface

6, 7, 8

371
Q

Lower neruovascular complex

A

PICA

Medulla

Inferior cerebellar peduncle

Cerebellomedullary fissure

Suboccipital cerebellar surface

9, 10, 11, 12

372
Q

Origin and course of SCA

A

Arises anterior to midbrain below CN3 (occasionally can arise from proximal PCA and pass over CN3)

Dips caudally and encircles brainstem near pontomesencephalic junction, passing below trochlear nerve and above trigeminal

Proximal portion courses close to the tenorial edge, distal below the tentorium

Enters cerebellomesencephalic fissure where it gives off the precerebellar arteries which supply deep cerebellar white matter and dentate nucleus

373
Q

Division of SCA

A

Divides into a rostral and caudal trunk

374
Q

Structures supplied by rostral trunk of SCA

A

Vermian and paravermian areas

375
Q

Structures supplied by the caudal trunk of SCA

A

Hemispheric suboccipital surface

376
Q

Segments of SCA

A

4 segments

Anterior pontomesencephalic

Lateral pontomesencephalic

Cerebellomesencephalic

Cortical

Each may be composed of one or more trunks

377
Q

SCA- anterior pontomesencephalic segment

A

Located between dorsum sella and upper brainstem

Begins at SCA origin and extends below CN3 to the anterolateral margin of brainstem

Lateral part is medial to the anterior half of the free tentorial edge.

378
Q

SCA- lateral pontomesencephalic segment

A

Second segment

Begins at the anterolateral margin of brainstem

Frequently dips caudally onto the lateral side of upper pons

Caudal loop projects to root entry zone of trigeminal at midpontine level.

Trochlear passes above midportion of this segment.

Caudal loop usually carries it below the tentorial edge.

Terminates at the anterior margin of cerebellomesencephalic fissure

Basal vein and PCA above and parallel.

379
Q

SCA- cerebellomesencephalic segment

A

Third part

Courses within cerebellomesencephalic fissure

SCA enters the shallowest part of the fissure above the trigeminal root entry zone and course medial to the tentorial edge.

Fissure progressively deepens- deepest in midline behind superior medullary velum.

SCA loops deeply and then passes upwards to the anterior edge of the tentorium.

380
Q

SCA- cortical segment

A

Fourth and final segment

Includes branches distal to the cerebellomesencephalic fissure that pass under the tentorial edge and is distributed to the tentorial surface and if marginal branch present to the upper part of the petrosal surface.

381
Q

Segments of AICA

A

Four

Anterior pontine segment

Lateral pontine segment

Flocculopeduncular segment

Cortical segment

382
Q

AICA- anterior pontine segment

A

First segment

Located between clivus and belly of pons

Ends at the level of a line drawn through the long axis of the inferior olive and extending upwards on the pons

May be in contact with rootlets of abducens

383
Q

AICA- lateral pontine segment

A

Second segment

Begins at the anterolateral margin of the pons and passes through the CPA in relation to CN 7 + 8, intimately related to the IAM, lateral recess and choroid protruding from the foramen of Luschke

384
Q

Subdivisions of lateral pontine segment of AICA

A

Premeatal

Meatal

Postmeatal

Based on relation to the porus acousticus

385
Q

Nerve-related branches of the lateral pontine segment of AICA

A

Labyrinth artery- CN VII, VIII, vestibulocochlear labyrinth

Recurrent perforating arteries

Subarcuate artery

386
Q

AICA- Flocculopeduncular segment

A

Begins where artery passes flocculus to reach middle cerebellar peduncle and CP fissure

May be hidden beneath flocculus or lips of cerebellopontine fissure

387
Q

AICA- cortical segment

A

Fourth and final part

Supplies predominantly the petrosal surface

388
Q

PICA segments

A

5 segments

Anterior medullary

Lateral medullary

Tonsillomedullary

Telovelotonsillar

Cortical

389
Q

PICA- Anterior medullary segment

A

First segment

Begins at PICA origin and extends past the hypoglossal rootlets to the level of a rostrocaudal line through the most prominent part of the inferior olive

If PICA arises lateral to the medulla then does not have an anterior medullary segment.

Usually passes posteriorly around or between hypoglossal rootlets

390
Q

PICA- Lateral medullary segment

A

Begins at the most prominent portion of inferior olive and ends at the level of origin of IX, X, XI rootlets

391
Q

PICA- Tonsillomedullary segment

A

Third segment

Begins where PICA passes posteriorly to IX, X, XI rootlets and extends medially along the posterior aspect of medulla near caudal half of tonsil

Ends where artery ascends to midlevel of medial tonsillar surface

Loop passing near the lower part of tonsil= caudal loop, can dip below the level of FM

392
Q

Relationship of the caudal loop of tonsillomedullary segment of PICA and cerebellar peduncle

A

Generally ends above or around the level of the caudal pole of the tonsil.

Cranial to the foramen magnum generally

393
Q

PICA- telovelotonsillar segment

A

Begins at the midportion of PICA’s ascent along the medial surface of tonsil towards the roof of fourth

Ends where PICA exits fissures between vermis, tonsil and hemisphere to reach suboccipital hemispheres

Forms cranial loop in most which is caudal to fastigium between cerebral tonsil below and tela choroidea and posterior medullary velum above

Gives rise to branches supplying tela choroidea and choroid plexus of fourth

394
Q

PICA- Cortical segment

A

Fifth and final segment

Beigns where trunks and branches leave groove between vermis medially and tonsil and hemisphere laterally

Includes terminal cortical branches

PICA bifurcation occurs near origin of this segment.

395
Q

Subclavian artery branches

VIT CD

A

Vertebral

Internal thoracic

Thyrocervical

Costocervical

Dorsal scapular

396
Q

Thyrocervical trunk branches

ISTA

A

I: inferior thyroid artery

S: suprascapular artery

T: transverse cervical artery

A: ascending cervical artery

397
Q

Costocervical trunk branches

SD

A

Supreme intercostal

Deep cervical artery

398
Q

Post-AComm clipping

Patient presenting with anterograde and retrograde amnesia, cognitive disturbance and confabulation

A

Subcallosal artery infarct

Perforator from AComm complex

Goblet sign

399
Q
A

Capsular artery of McConnell

400
Q
A
401
Q

Difference between duplicated and accessory MCA

A

Duplicated- second MCA arises from ICA

Accessory- second MCA from ACA

402
Q

Describe the vascular territories of the thalamus

A

Four vascular territories

Chiefly supplied by small perforating end-arteries from the PCA

Anterior: polar arteries, PComm

Paramedian: thalamoperforating branches from the P1 segment of the PCA (either unilateral or bilateral)

Lateral: Thalamogeniculate artery from P2

Posterior: Medial posterior choroidal artery or posterior branch of lateral posterior choroidal artery

May also receive additional blood supply form the anterior choroidal artery

403
Q

Draw the blood supply of the thalamus

A
404
Q

What constitutesthe carotid siphon

A

The lower half of the S is formed predominantly by the intracavernous portion

Upper half by the supraclinoid portion

405
Q

Why is the anterior choroidal seen before PComm when exposing the carotid above the ophthalmic artery?

A

AChA seen first even though it is more distal as:

C6/7 passes upwards posterolateral placing AChA origin lateral from the midline

AChA commonly arise further laterally from the posterior wall

AChA pursues a more lateral course

406
Q

Infundibular arteries

A

Group of arteries originating from PComm and distributed to the infundibulum

Fewer in number than superior hypophyseal arteries

407
Q

Which hypophyseal vessel supplies the anterior pituitary and stalk?

A

Superior hypophyseal

408
Q

What proportion of ophthalmic arteries arise within the cavernous sinus

A

8%

409
Q

Location of ophthalmic artery origin

A

Below optic nerve in supraclinoid region

Above dural roof of cavernous sinus

Pass anterolaterally below optic nerve to enter optic canal

410
Q

What can be done to improve ophthalmic artery exposure?

A

Removal of anterior clinoid process and roof of the optic canal

Incising falciform process (a thin fold of dura that extends medially from ACP)

411
Q

Premamillary artery

A

AKA Anterior thalamoperforator/ Polar arteries

Largest branch arising from PComm

Enters floor of third in front of mamillary body

Supplies posterior hypothalamus, anterior thalamus, posteiror limb of IC and subthalamus

412
Q

Segments of anterior choroidal

A

Cisternal

Plexal

413
Q

Cisternal segment of AChA

A

Origin to the choroidal fissure

Divided at the anterior margin into a proximal and distal segment

414
Q

Plexal segment of AChA

A

One or more branches that pass through choroidal fissure to branch and enter the choroid plexus of the temporal horn

415
Q

Basis of AChA clipping for Parkinsonism

A

Coopers tore the AChA whilst performing a pedunculotomy and had to clip it and terminate the operation

There was a disappearance of tremor and rigidity with preservation of voluntary motor function

Thought to be due to ischaemic necrosis of GP

416
Q

Coopers technique of AChA clipping for Parkinsonism

A

2 clips, one at origin and one 1.5cm from origin distal to pallidal branches

Distal clip thought to prevent retrogade filling

417
Q

Coopers AChA clipping outcomes

A

Good relief of tremor and rigidity

20% morbidity, 6% mortality

Hemiplegia, partial aphasia, HH

Several patients developed memory loss and confusion

Not uncommon for patients to remain somnolent for up to 10 days

418
Q

M1 and M2 boundary

A

M1 becomes M2 at the genu

The M1 can be subdivided into a pre and post bifurcation part

419
Q

Boundary of M2 and M3

A

M2 starts at the genu where the MCA passes over the limen insula

Terminates at the circular sulcus of insula

420
Q

Boundary of M3 and M4

A

M3 segment begins at circular surface of insula and ends at the surface of the Sylvian fissure

421
Q

What proportion of lenticulostriate perforators are prebifurcation

A

Around 80%

Remainder are post bifurcation

Few may arise from proximal M2

The earlier the bifurcation, the higher the number of post-bifurcation lenticulostriates

422
Q

Divisions of lenticulostriate arteries

A

Medial- tends not to branch before entering anterior perforated substance

Intermediate- complex arborised array with one large feeder

Lateral

423
Q

What proportion of MCAs bifgurcate

A

80%

424
Q

What proportion of MCAs trifurcate

A

12$

425
Q

Categorisation of MCA bifurfcations

A

Equal bifurcation

Superior trunk dominant

Inferior trunk dominant

Based on diameter and size of cortical area supplied

426
Q

How to differentiate between accessory MCA and recurrent artery of Heubner?

A

The recurrent artery of Heubner enters the anterior perforated substance

Accessory MCA sends branches to but courses laterally to anterior perforated substance

427
Q

Sensorimotor hempiplegia

Without receptive dysphasia

A

Superior trunk occlusion

428
Q

Receptive aphasia in absence of hemiplegia

A

Inferior MCA trunk occlusion

429
Q

Pericallosal artery vs Callosomarginal

A

Pericallosal arises at the ACommA

Callosomarginal arises from pericallosal to course along cingulate sulcus, can arise just distal to AComm or at any site along pericallosal

Pericallosal origin is not the junction with callosomarginal branch as the callosomarginal is variably present

430
Q

What is the only anaotmic variant tat correlates with loation of cerebral aneurysm?

A

A1 hypoplasia, found in 85% of AComm aneurysm

Most common site in the CoW for hypoplasia

431
Q

Crural monoplegia

A

Lower limb monoplegia

432
Q

Short pericallosal artery

A

Short arteries arising from pericallosal artery and perforating directly into corpus callosum

Can also supply septum, anterior pillars of fornix and commissure

433
Q

Long pericallosal arteries

A

Long vessels also arising from pericallosal and course parallel between it and the surface of the corpus callosum

434
Q

Precallosal artery

A

Infrequently occuring Acomm or A2 branch that passes upwards like a long callosal artery between pericallosal and lamina terminalis sending branches to anterior diencephalon

435
Q
A

NSx Neuroanatomy (25 decks)

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