Blood Supply, Hemorrhage, Herniation

Question 1

What kind of circulation does the ICA do?

Answer 1

Anterior

Question 2

Cervical part ICA

Answer 2

Bifurcation to carotid canal, anterior to transverse processes of upper 3 vertebrae

Question 3

Petrous part ICA

Answer 3

Carotid canal in petrous part of temporal b. Upward and medially above foramen lacerum.

Question 4

Cavernous part ICA

Answer 4

Within the cav sin. Surrounded by sympathetic plexus, CN III, IV, VI, and V1.

Question 5

What kind of circulation does vertebral A do

Answer 5

Posterior circulation

Question 6

Cervical part Vertebral A

Answer 6

Through transverse foramina of C1-6

Question 7

Atlantic part vertebral a

Answer 7

Perforates the dura and arachnoid. Passes thru foramen magnum. Acute angle is clinically important.

Question 8

Intracranial part vertebral a

Answer 8

Within the cranium. Unites at the caudal border of the pons, making the basilar a.

Question 9

Describe vertebral basilar insufficenecy

Answer 9

Inadequate blood flow through the posterior circulation of the brain, supplied by the 2 vertebral arteries that merge to form the basilar artery.

Due to severe hyperextension of the head (acute angle; compresses VA between C1 and occipital) or severe rotation (causes torsion w/ resulting narrowing; Bow Hunters)

Question 10

Describe subclavian steal syndrome

Answer 10

Blood flows away from the brain due to an occlusion that’s proximal to the vertebral A off the subclavian.

As blood flows up the RCC then into the R sublavian as normal, it reaches an occlusion proximal to vertebral. This causes the blood to “come down” from the vertebral A to supply the upper limb.

This leads to decreased blood flow in the brain because vertebral blood is stolen by the subclavian!

Question 11

If there is a deficit of CN II, which arteries could be at fault?

Answer 11

ICA
Anterior cerebral A
Anterior communicating A

Question 12

If there is a deficit of CN III, which arteries could be at fault?

Answer 12

Posterior communicating A (more liekely P1)
Posterior cerebral A
Superior cerebellar A
Quadrigeminal A

“Oculomotor sandwich”

Question 13

If there is a deficit of CN V, which arteries could be at fault?

Answer 13

Pontine As
Superior cerebellar A
Basilar A

Question 14

If there is a deficit of CN VI, which arteries could be at fault?

Answer 14

Anterior inferior cerebellar A
Vertebral A
Basilar A

Question 15

If there is a deficit of CN VII, which arteries could be at fault?

Answer 15

Anterior inferior cerebellar A

Labyrinthine A

Question 16

Which artery runs in between CN XI and CN X

Answer 16

Posterior inferior cerebellar A

Note, CN XI runs inferiorally and passes through posterior spinal A

Question 17

CN XII is “cornered” by which 2 arteries?

Answer 17

Posterior inferior cerebellar A and vertebral A

Question 18

Which arteries are NOT part of the CoW?

Answer 18

MCA
Anterior choroidal A
Ophthalmic A

Question 19

Where is CoW located?

Answer 19

In the subarachnoid space w/ CSF and veins

Question 20

Which arteries branch off the Basilar A?

Answer 20

Anterior inferior cerebellar A (AICA)
Pontine A
Superior cerebellar A
Basilar A terminates into the posterior cerebral A. (P1 and P2, P1 is more medial)

Question 21

What arteries does the posterior communicating A connect?

Answer 21

posterior communicating arteries are arteries at the base of the brain that form part of the circle of Willis.
Each posterior communicating artery connects the three cerebral arteries (posterior, middle, and anterior) of the same side.

Question 22

What is a “border zone” and what are they susceptible to

Answer 22

Areas between arteries. Susceptible to damage under sudden systemic hypotension of hypoperfusion b/c there are no anastomotic connections.

Question 23

ACA supply

Answer 23

Medial and superior surface of frontal and parietal lobes

Question 24

MCA supply

Answer 24

Lateral surface of frontal and parietal. Superior temporal.

Question 25

PCA supply

Answer 25

Occipital and inferior temporal.

Question 26

Issues involved with ACA/MCA border zone

Answer 26

Motor, sensory, language, behavior

Question 27

Issues involved with MCA/PCA border zone

Answer 27

Visual and language

Question 28

Arteries in the CoW

Answer 28

CAIC PB | Ant. comm. A, Ant. cerebral A, ICA, Post. comm. A, Post. cerebral A, Basilar A

Question 29

Arteries supplying the brain stem

Answer 29

SPA VP | Superior cerebrellar A, pontine A, Anterior inferior cerebellar A, Vertebral A, Posterior inferior cerebellar A

Question 30

Arteries supplying pons and midbrain

Answer 30

SPA B | superior cerebellar A, pontine A, AICA, Basilar A

Question 31

Arteries supplying the medulla

Answer 31

posterior inferior cerebellar A, vertebral A, AICA

Question 32

A1

Answer 32

Precommunicating segment | ICA to anterior communicating A

Question 33

A2

Answer 33

Infracallosal segment | Anterior communicating A to where rostrum and genu of corpus callosum meet

Question 34

A3

Answer 34

Precallosal segment | Goes around genu and ends when vessels turn caudal

Question 35

A4

Answer 35

Supracallosal | Above corpus callosum

Question 36

A5

Answer 36

Postcallosal | Caudal (behind) corpus callosum

Question 37

M1

Answer 37

Sphenoidal or horizontal segment | ICA to bifurcation @ insula

Question 38

M2

Answer 38

Insular segment | Bifurcation at insula to circular sulcus of insula (right angle turn)

Question 39

M3

Answer 39

Opercular segment | Circular sulcus of insula to external surface of lateral fissure

Question 40

M4

Answer 40

Cortical segment | On the cortex

Question 41

Where do M3 and M4 come out from

Answer 41

Lateral sulcus for M4 to get onto cortex.

Question 42

P1

Answer 42

Basilar bifurcation to posterior communicating A

Question 43

P2

Answer 43

Posterior communicating A to around the midbrain

Question 44

P3

Answer 44

Quadrigeminal segment within the quadrigeminal cistern

Question 45

P4

Answer 45

Cortical segment

Question 46

Nervous tissue supplied by Anterior spinal A

Answer 46

Hypoglossal nucleus, medial lemniscus (sensory tract), and pyramid (motor tract)

Question 47

Nervous tissue supplied by posterior inferior cerebeallar A

Answer 47

DIMA SSRN ``` Dorsal motor nucleus of vagus (autonomics) Medial vestibular nucleus Inferior vestibular nucleus Accessory cuneate nucleus Solitary tract and nucleus Spinal trigeminal tract and nucleus Rubrospinal tract (motor tract) Nucleus ambiguous ```

Question 48

Nervous tissue supplied by basilar A branches

Answer 48

C MAMA ``` Abducens nucleus Median longitudinal fasciculus Absucens nerve Medial lemniscus Corticospinal fibers ```

Question 49

What does P1 segment of PCA supply

Answer 49

MORS Oculomotor nucleus Medial longitudinal fasciculus Red nucleus Substantia nigra

Question 50

What artery supplies the dorsal columns of the spinal cord

Answer 50

Posterior spinal A

Question 51

what artery supplies almost all of the dorsal and ventral horn

Answer 51

Sulcal A

Question 52

Describe epidural hematoma (where, bleeding source, sx)

Answer 52

Potential space between skull and dura, lens shaped Middle cranial fossa Due to temporal or pterion fx MIDDLE MENINGEAL A Unconsciousness, lucidity, acute sx, coma

Question 53

Describe subdural hematoma (where, bleeding source, sx)

Answer 53

Potential space between sura and arachnoid, crescent-shaped Head strikes a fixed object VENOUS- BRIDGING AND CORTICAL VS. OPEN INTO SUP. SAG. SIN. Slower onset, self limiting

Question 54

Describe subarachnoid hematoma (where, bleeding source, sx)

Answer 54

Beneath arachnoid RUPTURED ANEURYSM OF CEREBRAL A; CoW Massive bleeding into CSF; worst HA; vary LOC

Question 55

Describe intracerebral or subpial hematoma (where, bleeding source, sx)

Answer 55

Bleeding into brain substance MIDDLE CEREBRAL A HTN or degenerative arterial disease; stab wound

Question 56

Describe supratentorial, infratentorial, and tentorial notch

Answer 56

Supra: above tentorium; falx cerebri divides Infra: below horizontal tentorium cerebelli Notch: continuation of the supra and infratentorial compartment

Question 57

Causes of herniation syndromes (6)

Answer 57

Hemorrhage, Mass, Trauma, Abscess, Infection, Metabolic condition. Can all increase ICP.

Question 58

Subfalcine herniation

Answer 58

Displace tissue beneath falx cerebri. ACA compression leads to compromised frontal and parietal lobes Could become transtentorial herniation Enlarged lateral ventricle

Question 59

Transtentorial herniation

Answer 59

Brain displaced downward toward tentorial notch Compromises upper brain stem, CN III,. May compress Basilar A and posterior cerebral A Decorticate and decerebrate rigidity Blood in posterior horn Wont be able to constrict pupils if CN III is affected bc parasympathetics run here

Question 60

Uncal herniation

Answer 60

Uncus and parahippocampal gyrus extrude over tentorium cerebelli and thru tentorial notch Impinge on midbrain and damage cerebral peduncle Kernoham phenomenon shifts the midbrain

Question 61

Tonsillar herniation

Answer 61

Cerebellar tonsils go thru foramen magnum | Compress medulla and upper cervical spinal cord (compromise cardiac and respiratory centers)