Anatomy of the CNS vasculature

Question 1

the brain receives arterial blood from which two pairs of arteries?

Answer 1

internal carotid arteries and the vertebral arterires

Question 2

where does the internal carotid artery enter the skull?

Answer 2

enters the cranial cavity through the base of the skull

Question 3

where does the vertebral artery enter the skull?

Answer 3

enters the cranial cavity through the foramen magnum

Question 4

what are the four segments of the internal carotid artery?

Answer 4

Cervical
Petrous
Cavernous
Cerebral

Question 5

how do the vertebral arteries traverse the neck?

Answer 5

by passing through foramina transversarium of cervical vertebrae.

Question 6

what does the circle of willis do?

Answer 6

Willis joins the major vessels that supply the right and left sides of the brain.

Question 7

what comprises the circle of willis?

Answer 7

The circle includes the major vessels to the cerebral hemispheres: the anterior, middle, and posterior cerebral arteries. The circle is completed by anterior and posterior communicating arteries.

Question 8

are variations of the circle of willis possible? so if yes, could a vessel be absent or small?what can we call this small vessel?

Answer 8

yes; yes; hypoplastic

Question 9

what do the vertebral arteries join to form on the anterior surface of the brainstem?

Answer 9

they join to form the basilar artery

Question 10

what do the vertebral and basilar arteries supply? when does the basilar artery terminate?

Answer 10

they supply the branches to the brainstem and cerebellum; terminates when it divides into the right and left posterior cerebral arteries

Question 11

what does the internal carotid artery branch into?

Answer 11

anterior and middle cerebral arteries

Question 12

what does the middle cerebral artery supply?

Answer 12

supplies the lateral surface of each cerebral hemisphere. It emerges from the lateral sulcus and radiates over the hemisphere.

Question 13

where are the branches of the anterior and posterior cerebral arteries prominent? what do the cerebral arteries supply?

Answer 13

on the basal and medial surfaces of each cerebral hemisphere; Cerebral arteries supply penetrating vessels to the interior of the cerebrum.
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Question 14

how is the cerebrum supplied? what functional areas are affected? what happens if these areas are disrupted?

Answer 14

Well-defined functional areas of the cerebrum are each supplied by a particular branch from one of the main cerebral arteries; Well-defined functional areas of the cerebrum are each supplied by a particular branch from one of the main cerebral arteries; Disruption of blood flow will cause a neurological deficit (or lesion). The nature of the deficit will depend upon the specific brain area supplied by the damaged vessel.

Question 15

what are the main branches derived from the vertebral and basilar arteries?

Answer 15

Superior cerebellar artery
Anterior inferior cerebellar artery
Posterior inferior cerebellar artery

Question 16

what adjacent structures supplies the brainstem?

Answer 16

Vertebral artery
Anterior spinal artery
Basilar artery
Posterior inferior cerebellar artery

Question 17

what is the blood supply to the spinal cord? what arteries arise from the thoracic aorta?

Answer 17

the anterior and posterior spinal arteries;

Posterior intercostal arteries

Question 18

what is given off from the posterior branch of the posterior intercostal artery? what stems off this and what do these supply?

Answer 18

a spinal branch; anterior and posterior radicular arteries supplying the anterior and posterior nerve roots

Question 19

what branches off the posterior intercostal artery?

Answer 19

a posterior branch

Question 20

does the spinal branch give rise to any structures? if so, what?

Answer 20

yes; medullary artery and these will connect with the anterior or posterior spinal artery and “reinforce” the arterial supply.

Question 21

in terms of arterial blood supply to the spinal cord, what does the vertebral artery within the cranial cavity give rise too?

Answer 21

left and right anterior and posterior spinal arteries.

Question 22

in terms of arterial blood supply to the spinal cord, this artery is found within the cranial cavity giving rise to left and right anterior and posterior spinal arteries.

Answer 22

the vertebral artery

Question 23

in terms of arterial blood supply to the spinal cord, what do the right and left anterior spinal arteries join to form? how is this structure and the left and right posterior spinal arteries reinforced?

Answer 23

they form an anterior spinal artery in the midline of the spinal cord; by branches derived from posterior intercostal arteries

Question 24

in terms of arterial blood supply to the spinal cord, how is the anterior spinal artery formed?

Answer 24

from the the left and right anterior spinal arteries

Question 25

what are the components of the blood supply to the spinal cord?

Answer 25

Vertical—anterior and posterior spinal arteries Horizontal—segmental arteries that originate from posterior intercostal arteries

Question 26

T/F, in terms of arterial blood supply to the spinal cord not all posterior intercostal arteries contribute equally to the spinal arteries. Name an example; what is the effect

Answer 26

T, In the lumbar region, one of the posterior intercostal arteries gives off a large branch, the Great anterior segmental medullary artery (of Adamkiewicz); a water shed area

Question 27

in terms of arterial blood supply to the spinal cord, what is a watershed area?

Answer 27

The uneven contribution from the posterior intercostal arteries creates “watershed areas”. These are regions where the arterial supply is tenuous.

Question 28

in terms of venous drainage of the brain, what do the cerebral veins drain into?

Answer 28

the dural sinuses

Question 29

in terms of venous drainage of the brain, can anastomoses form, if so, where?

Answer 29

yes; they form between superficial and deep cerebral veins

Question 30

in terms of venous drainage of the brain, how many routes of drainage did we study?

Answer 30

3

Question 31

in terms of venous drainage of the brain, name the three routes of venous drainage

Answer 31

Superficial cerebral veins -> deep cerebral veins -> internal cerebral vein-> Great cerebral vein (of Galen )-> straight sinus -> transverse sinus-> sigmoid sinus Superficial cerebral vein->superior sagittal sinus-> transverse sinus-> sigmoid sinus Superficial cerebral vein-> inferior sagittal sinus-> straight sinus->transverse sinus-> sigmoid sinus

Question 32

what is the main route of venous drainage from the brain? are accessory veins present?

Answer 32

the internal jugular vein; yes, Though a vertebral vein runs along with the vertebral artery in the transverse foraminae, the vein provides only an accessory route of drainage for the brain

Question 33

n terms of venous drainage of the brain, what are other accessory routes of venous drainage?

Answer 33

include emissary veins, superior ophthalmic vein, and pterygoid plexus.

Question 34

in terms of venous drainage of the spinal cord, what are the two main plexi? their significance?

Answer 34

The internal and external venous plexus connect veins in the lumbar region (and pelvis) to veins in the brain.

Question 35

in terms of venous drainage of the spinal cord, what is the clinical relevance of the internal and external venous plexi?

Answer 35

These veins can be the route for malignant cells to metastasize from the pelvis (in the case of prostate cancer) to the brain.

Question 36

what are the three Extracerebral Hemorrhages?

Answer 36

epidural subdural subarachnoid

Question 37

what is epidural hematoma?

Answer 37

it happens above the dura layer, underneath the bone, the meningeal artery is ruptured, it accumulates faster because of the high pressure

Question 38

what is the subdural hematoma?

Answer 38

forms underneath the dura mater, bleeding develops slower from the bridging vein

Question 39

what is the subarachnoid hematoma?

Answer 39

bleeding, patients states worse headache of their life, occurs around the base of the brain where subarachnoid, found in circle of willis and bleed into space causing lots of pain

Question 40

how do Berry Aneurysms occur?

Answer 40

occur in vessels at the base of the brain. Rupture of berry aneurysms is the most frequent cause of subarachnoid hemorrhage.

Question 41

what does the intracerebral hemorrhage involve? name example?

Answer 41

involves the rupture of a vessel within the brain parenchyma; a vessel supplying the basal ganglia has ruptured.

Question 42

what is an important source of blood flow disturbance in the brain? the effect of these disturbances? what does ischemia result in?

Answer 42

cerebrovascular disease; Such disturbances may interfere with the delivery of blood and result in ischemia; Ischemia will result in hypoxia, which describes a lack of oxygen.

Question 43

what is ischemia?

Answer 43

local anemia due to mechanical obstruction

Question 44

what is hypoxia?

Answer 44

less than normal amounts of oxygen

Question 45

what is emboli?

Answer 45

any plug that blocks a blood vessel

Question 46

what is thrombus?

Answer 46

a plug formed of blood elements

Question 47

what are the different types of cerebral venous thrombosis?

Answer 47

superior cerebral vein, medial and posterior inferior internal cerebral

Question 48

what does cerebral venous thrombosis cause?

Answer 48

ischemia, so as a result, the vein becomes blocked and so oxygen delivery is impaired and an infarction occurs. The location of the infarct and the neurological deficit depends upon which vein becomes blocked.