CNS vasculature Flashcards
Which arteries supply the posterior part of the brain? Where do they arise from and where do they insert?
The right and left vertebral arteries, they arise from subclavian arteries ascend through transverse foramina of cervical vertebra and enter the cranial cavity via foramen magnum
Which arteries supply the anterior parts of the brain? Where do they come from and where do they insert?
The Internal carotid arteries (right and left) arrive as a terminal branch off of the common carotid arteries, they ascend through the neck to base of skull and enter through carotid canal.
What exactly do the vertebral arteries supply
Each vertebral artery and its branches supply the spinal cord, brainstem, cerebellum, occipital lobe, temporal lobe (some) and diencephalon (some)
What is the basilar artery
At the pontomedullary junction the right and left vertebral arteries unite and form it
What are the spinal arteries?
The anterior and posterior spinal arteries arise from the vertebral arteries and supply the spinal cord
Anterior Spinal Artery
Arises from vertebral arteries, and unites to form a single artery that travels through the midline of the spinal cord up to(but not including) the dorsal horn
Posterior spinal arteries (2)
arise from vertebral arteries and travel just posterior to dorsal horn of the spinal cord (bilateral)
What supplies the upper cervical spinal cord?
Branches from the Vertebral Artery
What are Radicular Arteries?
Branches of the posterior intercostal arteries that reinforce the anterior and posterior spinal artiers.
What is the radicular artery at T12
The Great Radicular artery, which may provide the entire arterial supply for the lumbosacra spinal cord
Posterior inferior cerebellar artery
arises from vertebral artery
Anterior inferior cerebellar artery
arises from caudal aspect of basilar artery
Pontine arteries
come from basilar artery
Superior cerebellar artery
arises from rostral aspect of the basilar artery
Internal auditory or labyrinthine artery
a branch of AICA supplies inner ear, its occlusion can lead to vertigo and ipsilateral deafness
Posterior cerebral arteries
termination site of basilar artery, it bifurcates into two posterior cerebral arteries
Blood supply to caudal medulla?
supplied by branches of the Anterior Spinal Artery, PICA and posterior spinal artery
Blood supply to rostral medulla?
supplied by branches of the anterior spinal artery, vertebral artery, and PICA
PICA
Posterior inferior cerebellar artery
Blood supply of pons? (general)
generally from basilar artery branches
blood supply of caudal pons?
basilar artery is supplemented by branches of the Anterior Inferior Cerebellar Artery
Blood supply to rostral pons?
basilar artery is supplemented by branches of superior cerebellar artery
Blood supply to midbrain (general)
Mainly supplied by posterior cerebral arteries and their branches
Blood supply to dorsal midbrain
from Superior cerebellar artery
Lesion to both posterior spinal arteries results in?
Loss of vibration and position sense in the entire body except for the head
A vascular lesion in the anterior spinal artery will result in?
Loss of pain temperature and motor function in the entire body except for the head
Wallenbergs Syndrome
Lateral medullary syndrome, caused by ischemia in territory of vertebral artery and or PICA.. Will cause decreased pinprick and temperature sensation in contralateral body and ipsilateral head.
Locked-in syndrome?
Caused typically by bilateral Ventral Pons ischemia, secondary to arthrosclerotic basilar artery steonosis with superimposed basilar thombosis. The patient is essentially unable to move and can only move eyes. Pontomesencephalic reticular formation of midbrain is spared so they are still self aware. It may also be caused by bilateral ventral midbrain ischemia secondary to lack of blood flow in rostral basilar artery which is much less common.
What is the circle of willis?
system of arteries that connect the anterior and posterior arterial cerebral circulation
Where in the Postcentral Gyrus does the ACA supply?
The medial portion
Where in the postcentral gyrus does the MCA supply?
The lateral portion
Lenticulostriate arteries
small branches of the middle cerebral arteries shich supply areas of the internal capsule and deep gray matter (like caudate putamen GPe GPi) they are small thin walled vessels and are frequent sites of stroke.
Blood brain barrier
protects brain from harm but allows things it needs through. It is formed by tight junctions between endothelial cells lining CNS capillaries, which limit flow of substances. Lipid soluble molecules can cross (like nicotine, ethanol, caffeine) Hydrophilic molecules need a carrier. Many medications cant cross
Layers of meninges
Dura mater (external) Arachnoid (intermediate) Pia mater (inner)
Dura Mater
two layers: External Periosteal, which is formed by periosteum and adheres to the skull. and Internal meningeal layer, a dense fibrous connective tissue layer.
Arachnoid
Immediately adjacent to the dura, conforms to shape of brain but does not dip into sulci it is very delicate just like my feelings
Pia Mater
adheres and contours to the brain
Dural reflections
at many locations the internal meningeal layer of the dura reflects inward, the two largest are the Falx cerebri and the Tentorium cerebelli. They form dural venous sinuses that receive deoxygenated blood
Falx cerebri
dural reflection that invaginates along longitudinal fissure between the two cerebral hemispheres
Tentorium cerebelli
dural reflection between occipital and temporal lobes and cerebellum
Dural venous sinuses
spaces formed by inward reflection of inner meningeal layer of dura, conveys deoxygenated blood from cerebral veins to internal jugular vein which carries blood to heart.
Flow of blood from brain
cerebral arteries-> capillaries-> cerebral veins-> venous sinuses-> internal jugular vein
Epidural space
potential space between cranium and periosetal layer of dura
Epidural hemorrhage/hematoma
bleeding into potential space between cranium and dura from a laceration/tearing of menengeal artery frequently happens with trauma/skull facture
Middle meningeal Artery
courses in periosteal layer of dura over temporal plate, the skull is thin here and its easy to fracture it.
Subdural space
potential space between dura and arachnoid
Subarachnoid space
between arachnoid and pia mater, is a true space that contains blood vessels and csf
Subarachnoid Hemorrhage/ Hematoma
typically an arterial hemorrhage 70% aneurysm may be related to trauma
