The anterior cerebral artery (ACA) branches sharply forward from the internal carotid artery (ICA) . It ascends over the corpus callosum and its branches provide the anterior 2/3 of the medial surface of the cerebrum. The middle cerebral artery (MCA) branches from the ICA while keeping its general course. It enters into the lateral fissure and its branches run above the insula and supply the anterior 2/3 of the inferior and lateral surfaces of the cerebrum. Try to identify some of the small branches of the MCA. The most medial is the anterior choroidal artery that supply the choroid plexus. Lateral to it, the thin striate arteries penetrate the anterior perforated substance and supply the striatum and internal capsule.
The
posterior
cerebral
artery
(PCA)
is
a
part
of
the
posterior
blood
supply.
In
their
superior
part,
the
two
vertebral
arteries
merge
to
form
the
basilar
artery
.
At
the
most
superior
part,
the
basilar
artery
splits
into
the
two
posterior
cerebral
arteries.
The
PCA
provides
the
posterior
1/3
of
the
cerebrum
surfaces.
The posterior choroidal arteries branch from the
PCA and supply the choroid plexus in the temporal horn of the lateral ventricles and the tela choroidea of the third ventricle.
The
main
arteries
that
supply
the
cerebrum
are
connected
in
an
arterial
circle
(circle
of
Willis)
.
This
circle
consists
of
the
two
anterior
cerebral
arteries
that
are
connected
by
the
anterior
communicating
artery
and the two
internal carotid arteries
that
are connected, right next to where the MCA branches, to the
posterior cerebral arteries
, through the
posterior communicating
arteries
.
Three arteries supply the cerebellum, they are all part of the posterior blood supply of the brain. The superior cerebellar artery branches from the rostral part of the basilar artery , below the posterior cerebral artery . Notice the oculomotor nerve that originates between them. Follow the basilar artery caudally, identify small branches that supply the pons, the pontine arteries . The anterior inferior cerebellar artery (AICA) branches from the lower part of the basilar artery near the merging point of the vertebral arteries . Try to find the thin labyrinthine artery that supply the inner ear and the abducens nerve that are located above it. The posterior inferior cerebellar artery (PICA) branches from the vertebral artery.
Blood supply of the cerebellum
​
Blood supply of the spinal cord
There are three main arteries that supply the spinal cord, they are part of the posterior blood supply of the brain.
In the superior part of the vertebral arteries, two small medial branches merge into the anterior spinal artery that supplies the anterior part of the spinal cord. Two posterior spinal arteries branch from the lateral part of each vertebral artery and supply the posterior part of the spinal cord.
On the lateral surface of the hemisphere, find the superior cerebral veins that drain into the superior sagittal sinus . Superficial to the lateral fissure, f ind the superficial middle cerebral vein that drains into the cavernous sinus. Two anastomotic veins branch from the superficial middle cerebral vein: the superior anastomotic vein (of Trolard) that drains into the superior sagittal sinus and the inferior anastomotic vein (of Labbe) that drains into the transverse sinus . It is difficult to differentiate between these veins and other veins in the preserved brain. In the depth of the lateral sulcus lies the deep middle cerebral vein . It is easier to identify it at its posterior part where the anterior cerebral vein drains into it and both form the basal vein (of Rosenthal) . This vein encircles the midbrain and drains into the great cerebral vein (of Galen) .
The internal venous system consists of two internal cerebral veins that lie within the tela choroidea of the third ventricle. Each such vein is formed from the drainage of the thalamostriate vein , septal vein and choroidal vein . Posteriorly, the two internal cerebral veins merge to form the great cerebral vein (of Galen) that also drains the basal vein . The great cerebral vein drains into the straight sinus .