Blood Supply, Hemorrhage and Herniation (Keim)

Question 1

Anterior circulation is through…

Answer 1

ICA

Question 2

Cervical part of the ICA:

Answer 2

Bifurcation to carotid canal

Anterior to the transverse process of upper 3 vertebrae

Question 3

Petrous part of the ICA:

Answer 3

Carotid canal in petrous part of temporal

Upward and medially above the foramen lacerum

Question 4

Cavernous part of the ICA:

Answer 4

In the cavernous sinus

Surrounded by sympathetic plexus, CN II, IV, VI and V1

Question 5

Cerebral part of the ICA:

Answer 5

Once it exits the cavernous sinus

Question 6

Posterior circulation comes from…

Answer 6

2 vertebral arteries

Question 7

Vertebral Artery:
Cervical part
Atlantic part
Intracranial part

Answer 7

• Transverse foramina of 1st 6 Cervical vertebrae
• the artery on laying on the groove on C1. Perforates the dura and arachnoid and passes through foramen magnum
• In the cranium, unite at the caudal border of pons to form basilar artery

Question 8

Vertebral Basilar insufficiency:

Answer 8

Reduce blood flow from vertebral arteries into the brain.
Could be due to severe hyperextension of head or extreme head rotation/Bow hunter’s syndrome.
Both could compress the arteries.

Question 9

Subclavian Steal syndrome:

Answer 9

Subclavian arteries are “stealing” blood from the vertebral arteries
Blood goes to the other side (opposite subclavian a.*) instead of the vertebral a.
Occurs when there is occlusion of the subclavian a. proximal to where the vertebral a. branches out

Question 10

What includes the Circle of Willis?

Answer 10

2 ICAs
2 ACAs
1 Anterior communicating artery
2 Posterior communicating arteries
2 Vertebral arteries 
1 Basilar artery
2 PCAs

Question 11

Is middle cerebral a. part of the circle of Willis?

Answer 11

No

Question 12

Anterior spinal artery supplies…

Labyrinthine (internal acoustic) artery supplies …

Answer 12

Spinal cord and medulla

Inner ear

Question 13

Optic N. relationships

Answer 13

Close proximity to ICA, ACA and the anterior communicating artery
Aneurysm in these vessels can compress the optic nerve and cause visual deficits

Question 14

Oculomotor N. relationships

Answer 14

Sandwiched between Posterior Cerebral a. And superior cerebellar a.
Close to posterior communicating artery
Aneurysm here could compress CN III and get oculomotor palsy

Question 15

Trigeminal N. relationships

Answer 15

Close to Superior Cerebellar A.

Aberrant Loops irritate the trigeminals and cause neuralgia

Question 16

Facial N. relationships

Answer 16

Close to Anterior Inferior Cerebellar a.

Aberrant loops can irritate CN VII

Question 17

Identify the Circle of Willis branches in this imaging study:

Answer 17

Ok

Question 18

Border zones (areas of coverage between Cerebral arteries) are susceptible to damage under …

Answer 18

Conditions of sudden hypotension or hypoperfusion

Question 19

ACA (Anterior cerebral artery supplies)
MCA supplies
PCA supplies

Answer 19

• medial and superior frontal and parietal lobes
• lateral frontal and parietal lobes and superior temporal lobe
• occipital lobe and inferior temporal lobe

Question 20

Boundaries of the segments of the ACA: 
A1
A2
A3
A4
A5

Answer 20

• ICA to anterior communicating a. (precommunicating segment)
• anterior communicating a. to where rostrum and genu corpus callosum meet (infracallosal segment)
• arches around the genu of corpus callosum, ends when vessels turn caudal (pericallosal segment)
• superior to corpus callosum (A4)
• caudal to corpus callosum (A5)

Question 21

Label the segments of the ACA:

Answer 21

Ok

Question 22

Label the arteries in this imaging study

Answer 22

Ok

Question 23

Identify the segments of the MCA

Answer 23

OK

Question 24

Middle Cerebral Artery segments 
M1
M2
M3
M4

Answer 24

• ICA to bifurcation at insula (sphenoidal or horizontal segment)
• bifurcation to circular sulcus of insula/right angle turn (insular segment)
• circular sulcus of insula to external surface of lateral fissure (opercular segment)
• on the cortex (cortical segment)

Question 25

Identify the arteries in this imaging study:

Answer 25

Ok

Question 26

``` Posterior cerebral artery segments P1 P2 P3 P4 ```

Answer 26

- basilar bifurcation to posterior communicating a. - posterior communicating a. to around the midbrain - segment within the quadrigeminal cistern (Quadrigeminal segment) - cortical segment

Question 27

Identify the segments of the PCA in this image

Answer 27

Ok

Question 28

Identify the segments of the PCA in this imaging study

Answer 28

Ok

Question 29

Medulla blood supply: Anterior spinal artery supplies … Posterior inferior cerebellar artery supplies …. Anterior inferior cerebellar artery supplies …. Posterior spinal artery supplies …

Answer 29

Medial aspect of the medulla Lateral aspect of the medulla Nuclei for CN VIII Dorsal parts

Question 30

Blood supply to pons: Paramedian branches of basilar supply…. Long circumferential branches of basilar supply

Answer 30

Medial pons | Lateral pons

Question 31

Blood supply to the Midbrain: PCA branches Anteromedial branches supply… Lateral branches of quadrigeminal supply ….

Answer 31

Medial Midbrain | Lateral midbrain

Question 32

Blood supply to forebrain: Thalamogeniculate branches of posterior cerebral artery supplies… Lenticulostriate arteries supply …. Anterior choroidal arteries supply ….

Answer 32

``` Lateral geniculate (vision) and medial geniculate nucleus (hearing) Internal capsule Portions of internal capsule ```

Question 33

Blood supply to spinal cord Posterior spinal arteries supply … Sulcal Arteries supply …. Anterior and Posterior spinal arteries supply….

Answer 33

Dorsal columns Most of the dorsal and ventral horns Corticospinal tract

Question 34

Meningeal spaces Epidural/extradural Subdural/dura-arachnoid interface Subarachnoid

Answer 34

- potential space between cranium and periosteal dura - potential space between dura and arachnoid mater - real space between arachnoid and pia mater, contains CSF, arteries (circel of willis) and veins

Question 35

Epidural hematoma Where is the bleeding? Common source? Clinical?

Answer 35

Bleeding between skull and dura in the middle cranial fossa Source is Middle meningeal a. Momentary unconsciousness followed by lucid period for 1-2 days, then unconsciousness. Lens image CT

Question 36

Subdural hematoma: Where is the bleeding? Common source? Clinical?

Answer 36

Bleeding between dura and arachnoid. Source is bridging vein Usually happens after head strikes fixed object Slower accumulation of blood due to pressure and often self limiting Crescent image on CT

Question 37

Subarachnoid hemorrhage: Where is the bleeding? Common source? Clinical?

Answer 37

Most common cause is rupture of aneurysm Source Is arterial circle of Willis Massive bleeding into CSF compartment with headaches and LOC Spider image on CT

Question 38

Intracerebral (subpial) hemorrhage Where is the bleeding? Common source? Clinical?

Answer 38

Bleeding within brain substance (stroke) Source is usually the middle cerebral a. Caused by hypertension or degenerative arterial disease

Question 39

Herniation syndromes:

Answer 39

-displacement of brain tissue | Caused by hemorrhage, tumor, trauma etc.

Question 40

herniation syndromes: Supratentorial compartment: Infratentorial compartment: Tentorial notch:

Answer 40

- above the tentorium cerebelli and divided into right and left by falx cerebri - below the tentorium cerebelli - continuation of the supra and infratentorial compartment

Question 41

Subfalcine/cingulate/falcine/falx herniation

Answer 41

Involves the supratentorial compartment Displacement of brain tissue under the falx cerebri Can compress the ACA (lower limb sensory and motor deficits) Can evolve into transentorial herniation

Question 42

Transentorial/central herniation:

Answer 42

Brain displaced downward toward the tentorial notch Compromises the upper brainstem, CN III (along with parasympathetics) and lower structures (may compress basilar and posterior cerebral arteries) Decorticate and decerebrate rigidity

Question 43

Uncal herniation:

Answer 43

Uncus and portions of the parahippocampal gyrus are extruded over edge of tentorium cerebelli. Also damage CN III (ipsilateral) and motor deficits (contralateral). Mid-brain impingement (cerebral peduncle).

Question 44

Tonsillar herniation

Answer 44

Cerebellar tonsils herniate through foramen magnum | Compression of medulla and upper cervical spinal cord (has cardiac and respiratory centers)

Question 45

Abducens N. relationships

Answer 45

Between labyrinthine and AICA

Question 46

Uncal herniation consequences:

Answer 46

Cerebral peduncle impingement. Results in oculomotor palsy in side of lesion and motor deficits on opposite side Kernohan phenomenon. Shifts the midbrain and impinges the peduncle. Same side motor and oculomotor deficits.