2. Blood Supply, Hemorrhage, and Herniation Flashcards

1
Q

What contributes to the blood supply to the brain and what are their parts?

A

Internal Carotid A (Cervical, Petrous, Cavernous, and Cerebral parts)

Vertebral A. (Cervical, Atlantic, and Intracranial part)

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2
Q

Where is the cervical part of the ICA?

A

At bifurcation to carotid canal, anterior to TV processes of upper 3 vertebrae

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3
Q

Where is the petrous part of the ICA?

A

carotid canal in petrous part of temporal, upward and medially above foramen lacerum

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4
Q

Where is the cavernous part of the ICA?

A

in the cavernous sinus; surrounded by sympathetic plexus, CN 3, 4, 6, and V1

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5
Q

Where is the cervical part of the Vertebral A.?

A

transverse foramina of first 6 cervical vertebrae

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6
Q

Where is the atlantic part of the Vertebral A.?

A

perforates dura and arachnoid, passes through foramen magnum; perforated atlantooccipital membrane as well

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7
Q

Where is the intracranial part of the Vertebral A.?

A

In the cranium; unites at caudal border of pons to form basilar A.

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8
Q

What supplies the anterior and posterior circulation respectively? What connects them?

A

Anterior, internal carotid A. branches

Posterior, posterior cerebral A.

Connects them= posterior communicating A.

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9
Q

What arteries are in close proximity to CN 2 in the Circle of Willis? What happens with an aneurysm in one of them?

A

ICA, Anterior cerebral A., and anterior communicating A.

Aneurysm could compress optic chiasm/nerve, as well as pituitary could compress–> leads to visual problems

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10
Q

What arteries are in close proximity to CN 3 in the Circle of Willis? What happens with an aneurysm in one of them?

A

Superior Cerebellar A. and posterior cerebral A.; posterior communicating A. also close

Aneurysm in these arteries could compress it as well- pupil affected first!!

PS fibers also travel alongside CN 3, so secondary motor problems with eyes can also occur

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11
Q

What arteries are in close proximity to CN 6 in the Circle of Willis? What happens with an aneurysm in one of them?

A

Anterior inferior cerebellar A., labyrinthine/internal accoustic a.

Aneurysm–> CN 6 palsy if compressed

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12
Q

What arteries are in close proximity to CN 5 in the Circle of Willis? What happens with an aneurysm in one of them?

A

Superior Cerebellar A., if have abberant BV, can cause trigeminal issues –> trigeminal neuralgia

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13
Q

What arteries are in close proximity to CN 7 in the Circle of Willis? What happens with an aneurysm in one of them?

A

Anterior inferior cerebellar A. (ACA) branches can compress facial nerve–> facial issues

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14
Q

What comprises the actual circle of willis?

A

Anterior communicating A., Anterior cerebral A. (A1), ICA, Posterior communicating A. and posterior cerebral A. (P2)

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15
Q

what arteries does vertebral A. give off?

A

anterior spinal A. and anterior inferior cerebellar A.

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16
Q

What does ICA give off?

A

anterior cerebral A. which gives off anterior communicating A.

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17
Q

What does the anterior cerebral A. supply?

A

supplies most of medial and superior surface of the frontal and parietal lobes

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18
Q

What does the middle cerebral A. supply?

A

supplies lateral surface of frontal and parietal lobes and superior part of temporal lobe

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19
Q

What does the posterior cerebral A. supply?

A

supplies the occipital lobe and inferior temporal lobe

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20
Q

What are border zones? what areas are most likely damaged!

A

areas between arteries

get them most likely between the ACA and the MCA; susceptible to damage under conditions of sudden systemic hypotension or hypoperfusion

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21
Q

What happens in posterior watershed infarcts?

A

Bw MCA and PCA; get visual disturbances and language issues

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22
Q

What happens in anterior watershed infarcts?

A

bw ACA/MCA; motor and sensory defecits to lower limb

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23
Q

What is the A1 segment?

A

Precommunicating segment: ICA to anterior communicating A.

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24
Q

What is the A2 segment?

A

Infracallosal segment: anterior communicating A. to where rostrum and genu of corpus callosum meet

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25
What is the A3 segment?
Precallosal segment: arches around genu of corpus callosum, ends when vessels turn caudal (bend)
26
What is the A4 segment?
Supracallosal: superior to corpus callosum
27
What is the A5 segment?
Postcallosal: caudal to corpus callosum
28
Where is the pericallosal artery?
adjacent to corpus collosum
29
What branches off anterior cerebral A. ?
pericallosal artery: adjacent to corpus collosum | callosomarginal A.: around cingulate gyrus area
30
What is the M1 segment?
sphenoidal or horizontal segment: ICA to the bifurcation at insula
31
What is the M2 segment?
Insular segment: bifurcation at insula to circular sulcus of insula (right angle turn)
32
What is the M3 segment?
Opercular segment: circular sulcus of insula to external surface of lateral fissure
33
What is the M4 segment?
cortical segment: on cortex
34
What arteries come off the M1 segments?
Lenticulostriate arteries
35
What is the P1 segment?
basilar bifurcation to posterior communicating a.
36
What is the P2 segment?
posterior communicating a. to around midbrain
37
What is the P3 segment?
quadrigeminal segment: segment within quadrigeminal cistern (posterior side)
38
What is the P4 segment?
Cortical segment
39
Describe the blood supply to the medulla (and deficits associated):
Anterior Spinal A.- medial medulla (medial medullary syndrome); area contains: pyramid, medial lemniscus, and hypoglossal nucleus posterior spinal A.- lower levels of medulla, faciculus cuneitis/gracilis, cuneite and gracile nucleus Posterior Inferior Cerebellar A. (PICA)- lateral medulla (lateral medullary syndrome/wallingberg); variety of nuclei Anterior inferior cerebellar A. - dorsal and ventral cochlear nuclei
40
Describe the blood supply to the pons and deficits associated:
Paramedian branches of basilar A.- medial aspects of the pons;(middle pontine syndrome) long circumferential branches of basilar A.- (lateral pontine syndrome)
41
Describe the blood supply to the midbrain:
Anteromedial (paramedian) branches of basilar bifurcation and P1- (Webers syndrome) Quadrigeminal (P3) and superior cerebellar arteries- serve superior and inferior colliculus
42
Describe the blood supply to the forebrain:
Telencephalon/diencephalon Thalamogeniculate branches of posterior cerebral A. (branch of P2)- thalamus and lateral/medial geniculate nuclei/bodies Anterior choroidal A.- hit optic tract and hippocampal formation; part of internal capsule Lateral striate branches (lenticulostriate arteries) of MCA- internal capsule also
43
Describe the blood supply to the spinal cord:
Anterior Spinal A.- most of the Dorsal and Ventral horns, as well as more of the area around; gives off Sulcal As. which ALTERNATE levels Posterior spinal A.- dorsal faciculus (gracile and cuneite); anastamose with arterial vasocorona (AVC); (cortical spinal tract organized in arms and legs; legs by dorsal spinal A. )
44
What happens if sulcal arteries of anterior spinal A. are occluded?
Will only affect one side of the medulla/spinal cord as they branch and stair step
45
What is the epidural meningeal space?
Extradural; it is a POTENTIAL space bw cranium and periosteal dura
46
What is the subdural meningeal space?
dura-arachnoid interface; it is a POTENTIAL spce bw dura and arachnoid
47
What is the subarachnoid meningeal space? What does it contain?
it is a REAL space!! bw arachnoid and pia contains CSF, arteries (circle of Willis), and veins
48
What is an epidural hematoma? Where is it common? what is the source of bleeding? Clinical? Tx?
bleeding into the epidural space Common site: fracture at squamous temporal bone of pterion Source of bleeding: MMA!! Clinical- momentary uncosciounsess followed by lucid periods of hours to 1-2 days then uncosciousness; seems normal then deteriorates Tx- surgical
49
What is the shape of an epidural hematoma?
lens shape (bw bone and dura/periosteal layers) many times in periosteal fossa
50
What is an subdural hematoma? Where is it common? what is the source of bleeding? Clinical? Tx?
Bleeding in subdural space (bw dura and arachnoid) Occurance- head strikes fixed object Source of bleeding: venous!! cortical veins opening into superior sagittal sinus Clinical- slower accumulation of blood due to pressure and often is self-limiting Tx- surgical
51
What is the shape of an subdural hematoma?
crescent shaped!! jagged
52
What is an subarachnoid hematoma? Where is it common? what is the source of bleeding? Clinical? Tx?
Bleeding in subarachnoid space common finding in severe head injury more common rupture of aneurysm (develop in circle of willis) Source of bleeding- arterial bleeding from CEREBRAL A. Clinical- massive bleeding into CSF compartment due to arterial source with headaches and deteriorating level of consciousness (HORRIBLE HEADACHE, ppl die)
53
What is an Intracerebral (Subpial) hemorrhage? source? clinical?
bleeding within brain substance (stroke), complication in 2-3% of all head injuries source is usually middle cerebral A. clinical- hypertension or degenerative arterial disease (commonly seen in autopsy); HTN and DAD
54
What is a herniation syndrome? causes?
Caused by Hemorrhage, mass/tumor, trauma, abscess, infection, metabolic conditions high intercranial pressure--> herniation
55
What are the divisions involved in herniation syndromes?
supratentorial compartment- above tentorium and divided into right and left by falx cerebri Infratentorial compartment- below tentorium cerebelli Tentorial notch- continuation of supra and infratentorial compartment
56
What is a subfalcine herniation? what can it compress? what can it evolve into?
also called a cingulate or falcine or falx herniation; get some kind of lesion (bleed or tumor) in supratentorial compartment, pushing brain to opposite compartment (push brain tissue under falx cerebri) This may compress the ACA, leading to motor or sensory deficits, in addition to others May evolve into a transtentorial herniation
57
What is a transtentorial herniatoin? What is compromised?
also called central herniation; brain displaced toward tentorial notch compresses midbrain structures (CN3, basilar A., and posterior cerebral A.) and upper brainstem is compromised visual issues decorticate rigidity, decerebrate rigidity
58
What is an uncal herniation?
uncus and frequently portions of parahippocampal gyrus are extruded over the edge of the tentorium cerebelli and through tentorial notch; impinging on midbrain !!
59
What are the types of uncal herniation?
contralateral hemiplesia and ipsilateral CN3 problems-- > damage cerebral peduncles where motor tracts running through Kernohans syndrome--> get uncal herniation and get shift of midbrain (pushes it to side); still disrupt and put traction on CN3, so now oppoiste cereberal peduncle compressed where motor tracts found--> ipsilateral CN3 palsy, ipsilateral hemiplesia (motor issues)
60
What is tonsillar herniation? what is compressed?
cerebellar tonsils through foramen magnum compression of the medulla and upper cervical spinal cord