Flashcards in export_blood supply to the cns Deck (153)
What are the three main proximal arteries/trunks that come off the subclavian vessels?
1. Vertebral artery
2. Thyrocervical trunk
3. 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?
1. Superior Thyroid - larynx and upper thryoid.
2. Ascending pharyngeal - nasopharynx/oropharynx
3. Lingual - tongue/floor of mouth
4. Facial - face
5. Occipital - posterior scalp/meninges
6. Posterior auricular - pinna, EAC, scalp.
7. Superficial temporal - scalp/ear
8. Internal maxillary - gives off MMA and acc mening
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?
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?
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?
1. Meningohypophyseal (posterior trunk)
2. Inferolateral/ artery of the inferior cavernous sinus.
3. Medial trunk/McConnell's capsular ateries
What are the branches of the meningohypophyseal trunk?
1. Tentorial artery/artery of Bernasconi and Cassinari. Supplies the tentorium.
2. Inferior hypophyseal artery - neurohypophysis.
3. 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.
CN 3, 4, 6 and the gasserian ganglion via the foramen ovale and spinosum.
Anastomses of the inferolateral trunk of the cavernous ICA?
1. 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?
2. Superior hypophyseal
3. Posterior communicating
4. 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,
2. anterior thalamus,
3. subthalamic nucleus,
4. 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?
1. Inferior optic chiasm, posterior optic tract, optic radiattions and lateral geniculate body.
2. Uncus, parahippocampal gyrus and amygdala.
3. Choroid plexus in the temporal horn and atrium.
4. Basal ganglia - globus pallidus medius, tail of caudate, internal capsule.
5. Subthalamus, lateral ventroanterior, ventrolateral thalamic nuclei.
6. Cerebral peduncle, upper red nucleus, substantia nigra.
Lie superior/superolateral to the origin of the AchA.