Anatomy of the CNS vasculature Flashcards
the brain receives arterial blood from which two pairs of arteries?
internal carotid arteries and the vertebral arterires
where does the internal carotid artery enter the skull?
enters the cranial cavity through the base of the skull
where does the vertebral artery enter the skull?
enters the cranial cavity through the foramen magnum
what are the four segments of the internal carotid artery?
Cervical
Petrous
Cavernous
Cerebral
how do the vertebral arteries traverse the neck?
by passing through foramina transversarium of cervical vertebrae.
what does the circle of willis do?
Willis joins the major vessels that supply the right and left sides of the brain.
what comprises the circle of willis?
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.
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?
yes; yes; hypoplastic
what do the vertebral arteries join to form on the anterior surface of the brainstem?
they join to form the basilar artery
what do the vertebral and basilar arteries supply? when does the basilar artery terminate?
they supply the branches to the brainstem and cerebellum; terminates when it divides into the right and left posterior cerebral arteries
what does the internal carotid artery branch into?
anterior and middle cerebral arteries
what does the middle cerebral artery supply?
supplies the lateral surface of each cerebral hemisphere. It emerges from the lateral sulcus and radiates over the hemisphere.
where are the branches of the anterior and posterior cerebral arteries prominent? what do the cerebral arteries supply?
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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how is the cerebrum supplied? what functional areas are affected? what happens if these areas are disrupted?
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.
what are the main branches derived from the vertebral and basilar arteries?
Superior cerebellar artery
Anterior inferior cerebellar artery
Posterior inferior cerebellar artery
what adjacent structures supplies the brainstem?
Vertebral artery
Anterior spinal artery
Basilar artery
Posterior inferior cerebellar artery
what is the blood supply to the spinal cord? what arteries arise from the thoracic aorta?
the anterior and posterior spinal arteries;
Posterior intercostal arteries
what is given off from the posterior branch of the posterior intercostal artery? what stems off this and what do these supply?
a spinal branch; anterior and posterior radicular arteries supplying the anterior and posterior nerve roots
what branches off the posterior intercostal artery?
a posterior branch
does the spinal branch give rise to any structures? if so, what?
yes; medullary artery and these will connect with the anterior or posterior spinal artery and “reinforce” the arterial supply.
in terms of arterial blood supply to the spinal cord, what does the vertebral artery within the cranial cavity give rise too?
left and right anterior and posterior spinal arteries.
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.
the vertebral artery
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?
they form an anterior spinal artery in the midline of the spinal cord; by branches derived from posterior intercostal arteries
in terms of arterial blood supply to the spinal cord, how is the anterior spinal artery formed?
from the the left and right anterior spinal arteries
what are the components of the blood supply to the spinal cord?
Vertical—anterior and posterior spinal arteries
Horizontal—segmental arteries that originate from posterior intercostal arteries
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
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
in terms of arterial blood supply to the spinal cord, what is a watershed area?
The uneven contribution from the posterior intercostal arteries creates “watershed areas”. These are regions where the arterial supply is tenuous.
in terms of venous drainage of the brain, what do the cerebral veins drain into?
the dural sinuses
in terms of venous drainage of the brain, can anastomoses form, if so, where?
yes; they form between superficial and deep cerebral veins
in terms of venous drainage of the brain, how many routes of drainage did we study?
3
in terms of venous drainage of the brain, name the three routes of venous drainage
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
what is the main route of venous drainage from the brain? are accessory veins present?
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
n terms of venous drainage of the brain, what are other accessory routes of venous drainage?
include emissary veins, superior ophthalmic vein, and pterygoid plexus.
in terms of venous drainage of the spinal cord, what are the two main plexi? their significance?
The internal and external venous plexus connect veins in the lumbar region (and pelvis) to veins in the brain.
in terms of venous drainage of the spinal cord, what is the clinical relevance of the internal and external venous plexi?
These veins can be the route for malignant cells to metastasize from the pelvis (in the case of prostate cancer) to the brain.
what are the three Extracerebral Hemorrhages?
epidural
subdural
subarachnoid
what is epidural hematoma?
it happens above the dura layer, underneath the bone, the meningeal artery is ruptured, it accumulates faster because of the high pressure
what is the subdural hematoma?
forms underneath the dura mater, bleeding develops slower from the bridging vein
what is the subarachnoid hematoma?
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
how do Berry Aneurysms occur?
occur in vessels at the base of the brain. Rupture of berry aneurysms is the most frequent cause of subarachnoid hemorrhage.
what does the intracerebral hemorrhage involve? name example?
involves the rupture of a vessel within the brain parenchyma; a vessel supplying the basal ganglia has ruptured.
what is an important source of blood flow disturbance in the brain? the effect of these disturbances? what does ischemia result in?
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.
what is ischemia?
local anemia due to mechanical obstruction
what is hypoxia?
less than normal amounts of oxygen
what is emboli?
any plug that blocks a blood vessel
what is thrombus?
a plug formed of blood elements
what are the different types of cerebral venous thrombosis?
superior cerebral vein, medial and posterior
inferior
internal cerebral
what does cerebral venous thrombosis cause?
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.
