VASCULAR ANATOMY Flashcards
ICA course
ascend in front of the _________, and enter the base of the skull through the _______ Within the cranium, the internal carotid artery lies in the _______ It then pierces the dura to begin its subarachnoid course.
transverse processes of the upper three cervical vertebrae
carotid canal.
cavernous sinus.
branches of the ICA
ophthalmic, anterior choroidal, anterior cerebral, middle cerebral, and posterior communicating branches.
segments of the ICA
(1) the ________extends from the origin of the internal carotid artery from the common carotid to the site where it enters the carotid canal, (2) the _________is the part of the artery as it courses through the petrous portion of the temporal bone, (3) the _________ courses through the cavernous sinus, and (4) the _________extends from the site of exit of the artery from the cavernous sinus to its bifurcation into the anterior and middle cerebral arteries.
cervical segment
intrapetrosal segment
intracavernous segment
cerebral (supraclinoid) segment
the first intracranial branch of the internal carotid as it courses through the cavernous sinus
OPHTHALMIC ARTERY: supplies the optic nerve and gives rise to the central artery of the retina
_________ artery arises from the internal carotid artery after it emerges from the cavernous sinus
anterior choroidal
supply of the anterior choroidal
supplies the optic tract, cerebral peduncles, lateral geniculate body, posterior part of the posterior limb of the internal capsule, tail of the caudate nucleus, uncus, amygdala, anterior hippocampus, choroid plexus of the temporal horn, and sometimes the globus pallidus
The anterior cerebral artery originates from the internal carotid artery lateral to the_______and courses ______ to reach the interhemispheric fissure, where it curves around the genu of the corpus callosum
optic chiasm
dorsal to the optic nerve
Branches of ACA
- Recurrent Artery of Heubner (Medial Striate Artery)
- Orbitofrontal Artery: supplies the orbital gyri at the base of the frontal lobe and part of the septal area
- Frontopolar Artery: supplies most of the pole of the frontal lobe.
- Callosomarginal Artery: terminal branch of the anterior cerebral arter
- ericallosal Artery: terminal branch of the anterior cerebral arter
supply of the Recurrent Artery of Heubner (Medial Striate Artery)
anterior limb and genu of the internal capsule and parts of the head of the caudate, rostral putamen, and globus pallidus.
segments of the MCA
the M1 ________ segment courses posterior and parallel to the sphenoid ridge;
the M2 _________segment lies on the insula (island of Reil);
the M3_________ segment courses over the frontal, parietal, and temporal opercula;
and the M4 ________ segment spreads over the cortical surface
(sphenoidal)
(insular)
(opercular)
(cortical)
The ________ connects the internal carotid artery with the posterior cerebral artery.
posterior communicating artery
The vertebral artery arises from the subclavian artery. It ascends within the ____________ (intraosseous segment), curves backward around the _______(atlantoaxial segment), and enters the cranium through the _________(intracranial segment).
foramina of the transverse processes of the upper six cervical vertebrae
lateral mass of the atlas
foramen magnum
Branches of the VA
posterior spinal: supply the posterior aspect of the medulla below the obex, as well as the posterior column and posterior horns of the spinal cord
anterior spinal: supplies the medullary pyramids and the paramedian medullary structures, as well as the anterior two-thirds of the spinal cord
posterior inferior cerebellar branches: the inferior surface of the cerebellum, dorsolateral surface of the medulla oblongata,
Meningeal branches: supply the meninges of the posterior fossa, including the falx cerebelli.
3 long circumferential arteries of the BA
Auditory A.: supplies the inner ear and root fibers of the facial nerve.
AICA: inferior surface of the cerebellum, the brachium pontis, and the restiform body, as well as the tegmentum of the lower pons and upper medulla.
SCA: It supplies the superior surface of the cerebellum, part of the dentate nucleus, the brachium pontis and conjunctivum, the tegmentum of the upper pons, and the inferior colliculus.
The main trunk of the posterior cerebral artery bifurcates into ______and _____branches
medial; parietooccipital and occipital (including calcarine) branches,
lateral: anterior and posterior temporal branches
Perforating branches supply the ______ ______, and the _______
cerebral peduncle,
mamillary bodies
mesencephalon.
HISTOLOGY OF CEREBRAL VESSELS
Thinner walls
Absent external elastic laminae
Presence of astrocytic processes
Presence of a perivascular reticular sheath consisting of arachnoid trabeculae
Cerebral capillaries are structurally similar to capillaries elsewhere, except for being surrounded by________
perivascular glial (astrocytic) processes.
COLLATERAL CIRCULATION
- Extracranial anastomoses
- Extracranial-intracranial anastomoses
- Intracranial anastomoses occur in the circle of Willis.
- vertebral and external carotids ipsi
- occur between branches of the external carotid and the ophthalmic artery.
- rete mirabile, a group of small vessels that connect meningeal and ethmoidal branches of external carotid arteries with leptomeningeal branches of cerebral arteries.
Superficial venous system
- SUPERIOR CEREBRAL GROUP:drain the dorsolateral and dorsomedial surfaces of the hemisphere and enter the superior sagittal sinus
- MIDDLE CEREBRAL GROUP: drain the inferolateral surface of the hemisphere, and open into the cavernous sinus.
- INFERIOR CEREBRAL GROUP: open into the cavernous and transverse sinuses.
Deep Venous System
- INTERNAL CEREBRAL VEIN: receives the terminal and septal vein.
- BASAL VEIN OF ROSENTHAL: It drains blood from the base of the brain.
- GREAT CEREBRAL VEIN (OF GALEN): receives the internal cerebral vein and the basal vein of Rosenthal to empty into the straight sinus (rectus sinus).
They serve as low-pressure channels for venous blood flow back to the systemic circulation.
CEREBRAL DURAL VENOUS SINUSES
The__________ drain into the superior and inferior sagittal sinuses
superficial cerebral veins
the inferior sagittal sinus is joined by the _____________ to form the straight sinus
great cerebral vein of Galen
An increase in arterial pressure ________impulses from baroreceptors, with ________ of sympathetic efferents to the cardiovascular system and _______of the cardiac vagus nerve, leading to a decrease in arterial pressure.
increases
inhibition
stimulation
Cerebral blood flow will be maintained with fluctuations in systolic blood pressure between ___________
200 and 50 mmHg.
A ________ in blood viscosity, as occurs in anemia, will ________ cerebral blood flow. On the other hand, an increase in viscosity, as occurs in polycythemia, will decrease cerebral blood
reduction
increase
The vessel lumen must be reduced by_________before a reduction in cerebral circulation occurs.
70 to 90 percent
The single most important factor controlling cerebral circulation is the phenomenon of _________
autoregulation
Thus cerebral blood vessels______ in response to an______ in intraluminal pressure and dilate in response to a reduction in intraluminal pressure
constrict
increase
