Neurovaculature Flashcards
Internal Carotid Artery terminal branches
Opthalmic a. (to orbit and retina)
• Passes through optic canal with CN II
• Occlusion symptoms: blindness
Anterior choroidal artery
• To choroid plexus in lateral ventricles, optic chiasm,
internal capsule, diencephalon, mesencephalon
Middle cerebral a. (MCA; terminal branch of ICA)
Cerebral Arterial Circle (of Willis)
• Internal carotid arteries • Anterior cerebral arteries (ACA) • Anterior communicating artery (Acom) • Connects left & right ACA • Posterior communicating arteries (Pcom) • Connects ICA to PCA • Posterior cerebral arteries (PCA; terminal branch of the basilar a.)
Berry (Saccular) Aneurysm
Cerebral aneurysms: • dilation of a vessel wall, usually an artery • may cause damage by compression of neighboring structures Berry aneurysms • Sack-like dilation of arterial wall • usually arise from arterial branching points near the cerebral arterial circle (of Willis)
Watershed infarct
inadequate perfusion
of border zones; 10% all brain infarctions;
many stem from hypertension
ACA-MCA watershed infarct
• Contralateral hemiparesis of lower
extremity
• Expressive language deficits
• Behavioral changes
MCA-PCA watershed infarct
- Partial visual loss
* Language deficits
Ventromedial medulla stroke
vertebral + anterior spinal aa.
CN XII Hypoglossal N. Motor Deficits • Tongue protrudes to ipsilateral side
Dorsolateral medulla stroke
posterior inferior cerebellar a.
CN X Vagus N. Motor Deficits • Ipsilateral vocal paralysis • Uvula deviates to contralateral side
Fusiform Atherosclerotic Aneurysm
Fusiform: large, symmetric, “spindle
shaped”
Atherosclerotic: formed by plaques and
the concentric buildup of thrombi (clots).
Arterial Supply of the Spinal Cord
Each aortic segmental artery (e.g. posterior
intercostal arteries in the thoracic segment) will give off spinal branches
Radicular arteries: supply the roots of the spinal nerves
Medullary arteries: anastomose with the anterior and posterior spinal arteries
Arterial vasocorona:
anastomotic ring of arteries that encircles the spinal cord
Great radicular artery (of Adamkiewicz) • Arises unilaterally from a segmental medullary artery at T12-L2 level • Largest segmental medullary artery • Supplies the lumbar and sacral spinal cord
Cerebral Arteriovenous Malformations (AVMs)
Congenital abnormal connection between cerebral arteries and veins (drain to sinuses) • Often asymptomatic • Detection rate: 1.4/100,000 per year (10% of the rate of intracranial aneurysm) • May rupture, causing hemorrhage • Most common age of hemorrhage is 15-20 years
Cavernous Sinus
• Located in the middle cranial fossa, on lateral body of
sphenoid bone
• Surrounds the internal carotid artery (cavernous
portion) and CN VI (abducens n.)
• Walls of the sinus contain CN III, IV, V1, and V2
• Connected bilaterally by the intercavernous sinuses
• Drainage:
• Anteriorly: superior and inferior opthalmic veins
• Inferiorly: pterygoid plexus
• Posteriorly: superior & inferior petrosal sinuses
Antegrade flow
At rest, blood drains anteriorly & inferiorly from the face (opthalmic vv, to facial v., to the internal jugular v.
Retrograde flow
intracranial hyperthermia (the
brain gets hot!), blood drains posteriorly through
the orbits (opthalmic vv.) to the cavernous sinus.
• Counter-current cooling
• Venous blood in the cavernous sinus cools arterial
blood in the internal carotid artery before it gets to
the brain.
Cavernous Sinus Thrombosis
Early symptoms: headache, abducens palsy
Advanced symptoms: exophthalmos, diminished pupillary
light reflexes, periorbital edema, sensory loss in upper
face
