Cerebral Blood Supply Flashcards
The anterior circulation is governed by the…
Internal carotid artery
The posterior circulation is governed by…
Vertebral artery
Where does the internal carotid artery originate from?
Common carotid artery at the carotid bifurcation (C4 - upper border of thyroid cartilage)
What is the path of the internal carotid artery?
i. Passes upwards in the carotid sheath (with IJV and CN10)
ii. Enters carotid canal
iii. s-shaped course through the canal in petrous part of temp bone
iv. passes superior to foramen lacerum
v. along carotid groove in the cavernous sinus
vi. winds around anterior clinoid process –> forward under dura mater of cavernous sinus
Identify the branches of the internal carotid artery.
i. Opthalmic artery
ii. Anterior choroidal artery
iii. Anterior cerebral artery
iv. Posterior communicating artery
v. Anterior communicating artery
Outline key features of the opthalmic artery.
- Path: branches off from the ophthalmic segment (C6) of the ICA passes through the optic canal into the orbit
- Supplies: the eye and orbital contents
Outline key pathway of the anterior choroidal artery.
A) Path: communicating segment (C7) of ICA –> passes backwards with optic tract –> around cerebral peduncles and reaches lateral geniculate body –> above uncus to enter inferior horn of lateral ventricle where it passes choroid plexus
What does the anterior choroidal artery supply?
a. optic tract
b. choroid plexus of lateral ventricles
c. deep structures of the cerebral hemisphere (i.e. basal ganglia, posterior limb + retrolenticular + sublenticular parts of internal capsule)
What happens following an occlusion of the anterior choroidal artery?
Major effects related to motor pathways and movement – internal capsule affected
Does the anterior choroidal artery have any branches?
Gives off very slender perforating branches that are vulnerable to rupture
What is the path of the anterior cerebral artery (ACA)?
a. Above the optic nerve longitudinal fissure
i. Near the genus of the corpus callosum, it gives of the callosomarginal artery that runs on and above the cingulate gyrus
ii. The remaining part of the ACA passes above the corpus callosum as the pericallosal artery
What does the ACA supply?
- Anterior cerebral artery superficial branches supply medial surface of frontal & parietal lobes
Functional areas supplied: - Medial aspects of primary motor &
somatosensory cortices (contralateral
lower limbs) – i.e. paracentral lobule - Ventromedial prefrontal cortex
- Unimodal motor + somatosensory
association areas - Limbic lobe (cingulate gyrus)
What is the effect of an ACA occlusion?
Paralysis + sensory loss to the contralateral lower limb
Identify branches of the ACA.
a. Medial striate artery (Recurrent artery of Huebner): arising from the A2 segment. joins the anterolateral central arteries to supply parts of the basal ganglia
b. Anteromedial central arteries supply the anterior limb of internal capsule
What does the anterior communicating artery do?
Unites the 2 ACA just before entering the longitudinal fissure
What does the posterior communicating artery do?
Connects the anterior and posterior circulation
What is the path of the Middle Cerebral Artery (MCA)?
Lateral sulcus –> superolateral surface of the brain + Insula
Emerges onto lateral surface of
cortex
What does the MCA supply?
- Lateral aspect of primary motor & primary somatosensory cortices (contralateral head, upper limb, trunk)
- Broca & Wernicke’s areas (dominant
hemisphere only) - Primary (and association) auditory area
- Dorsolateral prefrontal cortex
- Unimodal motor + somatosensory
association areas - POT association area
What are the branches of the MCA?
Anterolateral group. (aka.
lenticulostriate/lateral striate/middle
striate aa.)
What is the origin of the vertebral artery?
Subclavian artery
What is the path of the vertebral artery?
i. Passes through successive transverse foramina C6-C1 vertebrae
ii. At C1, it pierces the dura mater to enter the cranial cavity through the foramen magnum
iii. R + L vertebral arteries pass the anterior surface of the medulla and unite to form the basilar artery at the pontomedullary junction
How is the basilar artery formed?
R + L vertebral arteries pass the anterior surface of the medulla and unite to form the basilar artery at the pontomedullary junction
How does the basilar artery terminate?
Terminates by dividing into posterior cerebral arteries
Identify branches of the vertebral artery from inferior to superior.
Posterior inferior cerebellar artery (PICA), posterior spinal artery, anterior spinal artery, meningeal branch of vertebral artery, labyrinth artery