export_blood supply to the cns Flashcards
What are the three main proximal arteries/trunks that come off the subclavian vessels?
- Vertebral artery
- Thyrocervical trunk
- Costocervical trunk
Following the bifurcation and before where do the ECA and ICA lie in relation to each other?
The ECA lies anteromedial to ICA at this point.
What are the major branches of the ECA?
- Superior Thyroid - larynx and upper thryoid.
- Ascending pharyngeal - nasopharynx/oropharynx
- Lingual - tongue/floor of mouth
- Facial - face
- Occipital - posterior scalp/meninges
- Posterior auricular - pinna, EAC, scalp.
- Superficial temporal - scalp/ear
- Internal maxillary - gives off MMA and acc mening
SALFOPS MAX.
What is the relationship of the cervical carotid artery to IJV.
CCA enters the carotid canal anteromedial to the IJV and is separated from it by cranial nerves 9, 10 and 11.
What are the segments of the ICA?
Cervical
Petrous
Cavernous
Cerebral/Clinoidal
Normal cerebral blood flow vs ischemic penumbra vs irreversible neuronal death.
Normal = 50
Ischemic penumbra= 8-23
Irreverisble neuronal death <8ml/100g of brain tissue.
What is the course of the petrous ICA?
Enters the carotid canal anterior to the IJV/jugular fossa, and lies behind the eustachian tube. Exits the canal at the petrous apex superior to the cartilage filled FORAMEN LACERUM.
Branches of the petrous ICA?
Caroticotympanic artery.
Vidian Artery/artery of the pterygoid canal.
Periosteal arterial branches.
Course of the intracavernous ICA?
Carotid canal and terminates at the entrance to the subarachnoid space adjacent to the anterior clinoid.
Relationship of the cavernous ICA to nervous structures in the cavernous sinus?
Its is covered by the trigeminal ganglion. CN 6 lies inferolaterally, CN 3, 4, 51 and 52 are lateral within the lateral dural wall.
What are the three arterial trunks of the intracavernous ICA?
- Meningohypophyseal (posterior trunk)
- Inferolateral/ artery of the inferior cavernous sinus.
- Medial trunk/McConnell’s capsular ateries
What are the branches of the meningohypophyseal trunk?
- Tentorial artery/artery of Bernasconi and Cassinari. Supplies the tentorium.
- Inferior hypophyseal artery - neurohypophysis.
- Dorsal meningeal artery - supplies CN 6 and the clivus.
What does the inferolateral trunk/artery of the cavernous sinus supply?
Inferolateral wall of the cavernous sinus.
Tentorium
CN 3, 4, 6 and the gasserian ganglion via the foramen ovale and spinosum.
Anastomses of the inferolateral trunk of the cavernous ICA?
- With the maxillary artery.
2. With the MMA and opthalmic artery.
What does the medial trunk of the cavernous ICA /McConnells capsular arteries supply?
The anterior and inferior pituitary gland.
The anterior capsular artery courses medially over the sellar roof.
The inferior capsular artery courses inferomedially and supplies the sellar floor.
What are the branches of the clinoidal/intradural ICA?
- Opthalmic
- Superior hypophyseal
- Posterior communicating
- Anterior choroidal
Couse of the opthalmic artery?
First intracranial ICA branch; rarely may arise of the MMA.
Arises superomedial or anteromedial to the ICA and under the anterior clinoid process. Initially inferolateral to CN 2 and medial to CN III and 6.
Aneurysms just distal to the opthalmic artery point where?
Aneurysms just distal to the opthalmic artery, arise from the superior wall of the ICA and point upward against the optic nerve.
Branches of the opthalmic artery?
Ocular branch - CRA and cilliary artery which supply the retina, choroid and optic nerve.
Orbital branches - lacrimal artery and muscular artery.
Extraorbital branches - several, have an extensive anastamotic network with the ECA via the ethmoidal and anterior falcine artery for collateral flow during ICA occlusion.
Superior hypophyseal arteries - course and area supplied?
Arise of the posteromedial intradural ICA and course beneath the optic nerve to supply the anterior pituitary, pituitary stalk and tuber cinereum
Also supply the optic nerve and chiasm.
Contribute to the hypophyseal portal system with the inferior hypophyseal ateries.
Aneurysms off the posteromedial intradural ICA point where?
Inferiorly and medially.
PcommA - course?
Arises from the posterior intradural ICA courses above CN III to join the horizontal PCA segment.
What does the PcommA supply?
Via seven perforators it supplies:
1. posterior hypothalamus,
- anterior thalamus,
- subthalamic nucleus,
- posterior limb of the internal capsule.
What is the largest perforator off of the PcommA?
Anteior thalamoperforating artery - terminates between the mamillary bodies and optic tracts.
What is a fetal PCA?
When the PcommA is the same diameter as the PCA - thus the occipital lobes are supplied by the ICA as opposed to the posterior/vertebrobasilar circulation.
PcommA/ICA aneurysms point where?
Arise off the posterior wall of the ICA and point posteriorly to CN III. the Pcomm usually lies inferomedially to the aneurysm, while the anterior choroidal should lie superolaterally.
Anterior choroidal artery - course?
Arises from the posteromedial ICA 2mm distal to the Pcomm. CISTERNAL segment courses posteromedially within the suprasellar cistern under the optic tract before turning posteromedially around the uncus.
INTRAVENTRICULAR segment - continues on - runs through the crural and ambient cisterns to enter the choroidal fissure of the temporal horn.
Anterior choroidal artery - supply?
- Inferior optic chiasm, posterior optic tract, optic radiattions and lateral geniculate body.
- Uncus, parahippocampal gyrus and amygdala.
- Choroid plexus in the temporal horn and atrium.
- Basal ganglia - globus pallidus medius, tail of caudate, internal capsule.
- Subthalamus, lateral ventroanterior, ventrolateral thalamic nuclei.
- Cerebral peduncle, upper red nucleus, substantia nigra.
AchA/ICA aneurysms.
Lie superior/superolateral to the origin of the AchA.
What are the main segments of anterior cerebral artery?
A1 - horizontal/precommunicating segment
A2 - vertical/postcommunicating segment
A3 - distal ACA and cortical branches
What arteries branch of the A1 segment?
The only arteries which branch off of the A1 segment are the MEDIAL LENTICULOSTRIATE arteries.
There are about 1-12 of these.
What do the medial lenticulostriate arteries supply and what is their course?
They course posterosuperiorly through the anterior perforated substance to supply the 1. optic nerve, 2. anterior hypothalamus, 3. septum pellucidum, 4. anterior commissure, 5. pillars of the fornix and the anteroinferior striatum.
The anterior communicating artery is located where?
Located in the cistern of the lamina terminalis.
The perforators that arise off of the AcommA supply what?
- Infundibulum
- Optic chiasm
- Subcallosal area
- Preoptic hypothalamus
Major peforators include the subcallosal artery and the medial artery of the corpus callosum
Describe A1/AcommA aneurysms - where they occur and where they point?
Arise where the dominant A1 bifurcates and they usually point to the CONTRALATERAL SIDE.
What are the major branches of the A2 segment?
- Recurrent artery of Heubner/medial distal striate artery.
- Orbitofrontal artery
- Frontopolar artery
- Anterior internal frontal artery
Course and vascular territory of the recurrent artery of Heubner?
Arises distal to the AcommA and courses back to the A1 and then enters the anterior perforating substance.
Supplies the 1. head of the caudate, 2. anterior limb of the internal capsule, 3. anterior putamen and globus pallidus. 4. septal nuceli 5. inferior frontal lobe.
Vascular territory of the orbitofrontal artery?
- Gyrus rectus.
- Medial orbital gyri.
- Olfactory bulb and tract.
Vascular territory of the frontopolar artery?
- Medial frontal lobe.
2. Lateral surface of the superior frontal gyrus.
Vascular territory of the anterior internal frontal artery?
Anterior medial frontal lobe
What are the major branches of the A3 segment?
- Callsomarginal
- Pericallosal
- Middle internal frontal
- Posterior internal frontal
- Paracentral
- Superior parietal
- Inferior parietal
Vascular territory of the callosomarginal?
Cingulate gyrus and paracentral lobule
2nd most common site for ACA aneurysms is?
The junction of the CALLOSOMARGINAL and PERICALLOSAL arteries.
Vascular territory of pericallosal artery?
Medial parietal cortex and the precuneus.
Vascular territory of middle internal frontal artery?
Medial frontal cortex
Vascular territory of posterior internal frontal artery
Medial posterior frontal cortex
Vascular territory of paracentral artery
Medial cortex around the central sulcus
Vascular territory of superior parietal artery?
Medial superior parietal lobe
Vascular territory of inferior parietal lobe
Medial inferior parietal lobe.
What are the segments of the MCA
M1
M2
M3
M4
What are the branches of the M1 branch?
- Uncal Artery (may come off the distal ICA)
- Temporopolar artery
- Anterior temporal artery
- Lateral lenticulostriate arteries
What is the course of the M1 segment?
The M1 segment/horizontal segment, extends horizontal and lateral beneath the anterior perforated substance, proximal to the bifurcation or trifurcation.
What is the course of the M2 segment?
This is the insular segment of the MCA and extends from the bifurcation to the genu, which courses around the island of Reil and heads posterosuperiorly into the Sylvian fissure.
What are the major trunks off of the M2 segment?
The SUPERIOR and INFERIOR trunks.
What are the branches off of the SUPERIOR TRUNK of the M2.
- Orbitofrontal branch
- Prefrontal branch
- Precentral branch
- Central branch
- Anterior parietal branch
What are the branches off of the inferior trunk of the M2 segment
- Posterior parietal branch
- Angular branch
- Temporooccipital branch
- Posterotemporal branch
- Middle temporal branch
What is the vascular territory of the uncal artery?
Uncus and underlying white matter
What is the vascular territory of the temporopolar artery?
Anterior pole of the superior, middle and inferior temporal gyri.
What is the vascular territory of the anterior temporal artery?
Anterior pole of the superior, middle and inferior temporal gyri.
What is the vascular territory of the lateral lenticulostriate artery?
- Substantia innominata
- Ant. commissure
- Putamen
- Globus pallidus
- Internal capsule
- Head and body of the caudate
What is the vascular territory of the orbitofrontal branch of the M2?
Orbital portion of the middle and inferior frontal gyri and the inferior pars orbitalis