Blood supply Flashcards
Two paired arteries which are responsible for the blood supply to the brain
Vertebral arteries
Internal carotid arteries.
What proportion and area do the vertebral arteries supply?
20% of the total, and supply the posterior part of the cerebrum and the contents of the posterior cranial fossa
What proportion and area do the internal carotid arteries supply?
Supply the remaining 80% and distribute to the anterior and middle parts of the cerebrum and the diencephalon.
Where is the circle of willis located?
The ‘Circle of Willis’ is located in the interpeduncular cistern and enclosing the optic chiasm
Where do the internal carotid arteries arise?
Bifurcation of the left and right common carotid arteries, at the level of the fourth cervical vertebrae (C4)
How do the internal carotid arteries enter the skull?
Carotid canal of the temporal bone.
Initial branches of the ICA?
Anterior cerebral artery and middle cerebral artery
Anterior cerebral artery branches and anastomoses
Gives off the short anterior communicating artery (connects with opposite anterior cerebral, circle of willis)
Posteriorly it anastomoses with branches of the posterior cerebral artery.
Middle cerebral artery supplies mainly
Lateral surface of the cerebral hemisphere
Internal carotid artery branches and anastomoses
A posterior communicating artery - which joins the posterior cerebral artery - ‘connecting vessel’ in the Circle of Willis
A small artery to the choroid plexus of the lateral ventricle.
The ophthalmic artery - supplies the structures of the orbit
Anterior choroidal artery - supplies structures in the brain important for motor control and vision.
Superior hypophyseal arteries - branch from the internal carotid arteries to supply the hypothalamus.
What is the ophthalmic artery a branch of?
ICA
Where does the ophthalmic artery arise?
First branch distal to cavernous sinus
Where do the superior hypophyseal arteries arise from?
ICA
Where does posterior communicating artery arise from?
MCA
What do the vertebral arteries arise from?
Subclavian arteries
How do vertebral arteries ascend?
Ascend the posterior aspect of the neck, through holes in the transverse processes of the cervical vertebrae, known as foramen transversum.
How do vertebral arteries enter the cranial cavity?
Foramen magnum
Branches of the vertebral arteries prior to basilar convergence
Meningeal branch – supplies the falx cerebelli, a sheet of dura mater.
Anterior and posterior spinal arteries – supplies the spinal cord, spanning its entire length.
Posterior inferior cerebellar artery – supplies the cerebellum.
Anterior inferior cerebellar artery - supplies cerebellum
Superior cerebellar artery - supplies cerebellum
What happens to the vertebral arteries at the lower border of the pons?
Vertebral arteries converge to form the basilar artery.
Where does the basilar artery travel initially?
Passes rostrally within the pontine cistern, lying in a shallow groove, the anterior median fissure, or basilar groove, of the pons.
How does the basilar artery terminate?
By bifurcating into the posterior cerebral arteries.
Where do the posterior cerebral arteries lie?
They can be seen at the rostral border of the pons, and can be traced some distance laterally around the cerebral peduncles towards the posterior surface of the cerebrum.
What do the posterior cerebral arteries supply?
The main terminal portions of the posterior cerebral arteries distribute to the occipital and temporal cortex.
Three main (paired) constituents of the Circle of Willis and two connecting vessels
Anterior cerebral arteries – terminal branches of the internal carotid arteries.
Internal carotid arteries – located immediately proximal to the origin of the middle cerebral arteries.
Posterior cerebral arteries – terminal branches of the basilar artery
Anterior communicating artery – connects the two anterior cerebral arteries.
Posterior communicating artery – branch of the internal carotid, this artery connects the ICA to the posterior cerebral artery.
Anterior cerebral arteries mainly supply
Anteromedial cerebrum
Posterior cerebral arteries mainly supply
Medial and lateral posterior brain
What are the three longitudinal arteries, that primarily supply the spinal cord as it descends from the brainstem to the conus medullaris?
Anterior spinal artery – formed from branches of the vertebral arteries, travelling in the anterior median fissure.
Gives rise to the sulcal arteries, which enter the spinal cord.
Two posterior spinal arteries – originate from the vertebral artery or the posteroinferior cerebellar artery,
Where do the two posterior spinal arteries anastomose
Pia mater
What arteries support the spinal cord supply from cervical level down?
Segmental medullary and radicular arteries.
Describe origin and passage of the anterior and posterior medullary arteries
The anterior and posterior segmental medullary arteries are derived from spinal branches of a number of arteries, before entering the vertebral canal through the intervertebral foramina.
The great anterior segmental artery of Adamkiewicz reinforces circulation to the inferior 2/3 of the spinal cord, and is found on the left in the majority of individuals.