The document provides an overview of the blood supply of the brain and sectional anatomy of the brain for dental students. It discusses the branches of the internal carotid and vertebral arteries, areas supplied by the cerebral arteries, and veins that drain the brain. Key structures in coronal and axial brain sections are identified, including the ventricles, basal ganglia, internal capsule, hippocampus, and limbic system. The objectives are to understand the vascularization and cross-sectional anatomy of the brain.

1. The Brain II
Blood Supply of the CNS
and Sectional Anatomy of the Brain
(for dental students)
Dr.Akram Abood Jaffar
Assistant Professor of Human Anatomy
M.B.Ch.B., M.Sc., Ph.D.
Dr. Akram Jaffar
Dr. Akram Jaffar

2. Objectives
Blood supply of the brain
Enumerate the branches of the internal carotid and vertebral arteries.
Map the areas of supply of the anterior, middle and posterior cerebral arteries.
Correlate areas of supply of cerebral arteries with functional cortical areas.
Describe the position, significance and formation of the circle of Willis.
Enumerate the veins draining the brain and the venous sinuses at which they drain.
Brain sections
Identify features of the cerebral hemispheres in coronal and axial sections at the level of the interventricular foramen.
Identify the boundaries of the third ventricle in a mid-sagittal section.
Describe the parts of the basal ganglia and their relation to the lateral ventricle.
Identify the parts and functions of the limbic system.
Describe the major functions of the thalamus and hypothalamus.
Describe how the hypothalamus controls the functions of the pituitary gland.
Identify the pineal gland, its function and clinical significance.
Describe the formation, circulation, and absorption of the CSF.
Discuss the properties and function of the CSF.
Describe the location and discuss the significance of the brain barriers: blood brain barrier & blood CSF barrier.
Further reading
• Snell RS (2010): Clinical neuroanatomy. 7th ed. Lippincott Williams and Wilkins.
Baltimore.
Dr. Akram Jaffar
Dr. Akram Jaffar

3. Blood supply of the brain
Dr. Akram Jaffar
Dr. Akram Jaffar

4. Arterial supply
Internal carotid a.
Vertebral a.
Dr. Akram Jaffar
Dr. Akram Jaffar

5. Internal carotid artery
• Enters the cranial cavity through the carotid
canal in the petrous temporal bone.
• Traverses the cavernous sinus.
• Pierces the roof of the cavernous sinus.
• Divides into anterior and middle cerebral
arteries.
middle cerebral a.
Anterior cerebral a.
Internal carotid a.
Dr. Akram Jaffar
Dr. Akram Jaffar

6. Branches of the internal carotid artery
Anterior cerebral artery
• Passes around the rostrum and genu of the corpus callosum.
• Supplies the medial aspect of the frontal and parietal lobes as far back as the parieto-
occipital sulcus and a small part of the adjacent lateral surface.
Corpus callosum
Anterior cerebral a. Effect of occlusion
Contralateral hemisenory loss
Contralateral hemiparesis
Personality changes
Leg and foot
Dr. Akram Jaffar
Dr. Akram Jaffar

7. Branches of the internal carotid artery
Middle cerebral artery
• Passes laterally into the lateral sulcus.
• Supplies the inferior surface of the frontal lobe,
the insula, and all save the periphery of the lateral
surface of the hemisphere.
middle cerebral a.
Contralateral hemisenory loss
Lateral sulcus
Contralateral hemiparesis
Aphasia Face and arm
middle cerebral a.
Effect of occlusion
Dr. Akram Jaffar
Dr. Akram Jaffar

8. Branches of the internal carotid artery
Other branches
Ophthalmic a.
• Ophthalmic artery  orbit
• Anterior choroidal artery  choroid
plexus of the lateral ventricle
• Posterior communicating artery 
posterior cerebral artery
Post. communicating a.
Ant. Choroidal a.
Post. cerebral a.
Dr. Akram Jaffar
Dr. Akram Jaffar

9. Vertebral artery
• Enters the cranial cavity through the
foramen magnum.
• Unites with its fellow of the opposite
side at the lower border of the pons
to form the basilar artery
Basilar a.
pons
Vertebral a.
Dr. Akram Jaffar
Dr. Akram Jaffar

10. Branches of the vertebral artery
• Anterior spinal artery
– Formed by the union of
branches from both vertebral
arteries.
Ant. spinal a.
– Descend in front of the medulla
to reach and supply the spinal
cord.
• Posterior inferior cerebellar artery
– Supplies the medulla, lower
cerebellum, choroidal branch to
the fourth ventricle, and a Ant. spinal a.
posterior spinal branch which
descends to the spinal cord. PICA
Dr. Akram Jaffar
PICA
Dr. Akram Jaffar

11. Branches of the basilar artery
• Anterior inferior cerebellar artery
• Pontine branches
• Labyrinthine artery
– Pass through the internal
acoustic meatus  inner ear Post. Cerebral a.
• Superior cerebellar artery
• Posterior cerebral arteries.
– At the upper pons
Ant. Inf. Cerebellar a.
Pontine branches
Sup cerebellar a.
Sup cerebellar a.
Post. Cerebral a.
Pontine branches
Ant. Inf. Cerebellar a.
Dr. Akram Jaffar
Dr. Akram Jaffar

12. Branches of the basilar artery
Posterior cerebral artery
• Passes backwards around the cerebral
peduncles to reach and supply:
– Medial surface of the occipital
lobe.
– Inferior surfaces of the occipital
and temporal lobes and the Post. Cerebral a.
adjacent lateral surface
Effect of occlusion
Impairment of memory
Dr. Akram Jaffar
Blindness
Dr. Akram Jaffar

13. Circle of Willis
• Anastomotic ring around the optic chiasma
and the pituitary gland.
• Provides anastomosis between internal
carotid and vertebral system of arteries. Optic chiasma
• Formation: Pituitary gland
– Anterior, middle and posterior cerebral
arteries
– anterior and posterior communicating
arteries
• Central arteries enter the brain through the
anterior and posterior perforated substances. Ant. communicating a.
central
Ant. cerebral a.
central
Middle cerebral a.
Post. communicating a.
Dr. Akram Jaffar
Post. Cerebral a.
Dr. Akram Jaffar

14. Venous drainage of the brain
• The veins draining the hemispheres may be divided into superficial and deep
veins.
Dr. Akram Jaffar
Dr. Akram Jaffar

15. Superficial group of veins
Superior cerebral veins passing to the
superior sagittal sinus
Superficial middle cerebral vein
passing in the lateral sulcus to
the cavernous sinus
Inferior cerebral
veins passing
to the
transverse
sinus
Dr. Akram Jaffar
Dr. Akram Jaffar

16. Deep group of veins
Anterior cerebral vein
Deep middle cerebral vein
Basal vein
Great cerebral vein
Internal cerebral vein
Basal vein
Great cerebral vein
Straight sinus
Dr. Akram Jaffar
Dr. Akram Jaffar

17. Sectional anatomy of the brian
Dr. Akram Jaffar
Dr. Akram Jaffar

18. Basal nuclei (ganglia)
claustrum
Caudate nucleus
insula
putamen
Globus pallidus
Caudate nucleus
Amygdaloid
body
Masses of grey matter located deep to the cortex in each
cerebral hemisphere
Basal ganglia
o Corpus striatum: is involved in the
Corpus striatum Claustrum Amygdaloid body
regulation of movement.
o Amygdaloind body: is concerned
Caudate nucleus Lentiform nucleus
with emotional behavior
o Claustrum: uncertain function
putamen
Dr. Akram Jaffar
Globus pallidus
Dr. Akram Jaffar

19. Ventricualr system
Lateral ventricle
rostrum
Interventricular Anterior horn
thalamus
foramen
us
3rd ventricle
lam
tha
Lateral ventricle
splenium
Posterior
horn
Transverse section just below the level of the corpus
Lateral ventricle callosum (at the level of the interventricular foramen)
Lateral ventricle
Lateral ventricle
Lateral ventricle
3rd ventricle
Cerebral
aqueduct
4th ventricle
• Lateral ventricle:
– Anterior horn
– Body
– Posterior horn
3rd ventricle
Interventricular
foramen – Inferior horn
Dr. Akram Jaffar
4th ventricle
Dr. Akram Jaffar

20. Internal capsule
claustrum
• band of projection fibers, appears
in a horizontal section as V- putamen
shaped.
• Connects the cerebral cortex with Globus
lower centers. pallidus
An
• Has an anterior limb, apex
te
rio
(genu), and a posterior limb.
rl
im
b
genu
P os
us
te
lam
rio
rl
t ha
im
b
Caudate
nucleus
Dr. Akram Jaffar
Dr. Akram Jaffar

21. Caudate nucleus Head
of
caudate
nucleus
thalamus
body
head tail
tail
• Is C-shaped in three dimensions
• Lies within the concavity of the lateral ventricle.
• Has an expanded head, a narrow body and a tail.
• Thus in a horizontal section only the head and tail of the caudate nucleus appear.
• The head of the caudate nucleus bulges into the medial wall of the anterior horn of the
lateral ventricle.
• The body of the caudate nucleus is located in the floor of the body of the lateral ventricle
Dr. Akram Jaffar
• The tail of the caudate lies in the roof of the inferior horn of the lateral ventricle
Dr. Akram Jaffar

22. Corpus striatum claustrum
putamen
o The head of the caudate nucleus and
the lentiform nucleus are connected by
fibers and grey matter across the Globus
anterior limb of the internal capsule pallidus
resulting in a striated appearance
(hence the name corpus striatum).
An
te
rio
rl
im
b
genu
P os
te
rio
rl
im
b
thalamus
Caudate
nucleus
Dr. Akram Jaffar
Dr. Akram Jaffar

23. Axial section of the brain
insula
putamen
Globus
pallidus
An
te
rio
Head
rl
Of
im
b
Caudate
genu nucleus
Po
st
er
or i
lim
b
thalamus
Dr. Akram Jaffar
MRI
Dr. Akram Jaffar

24. The limbic system
fornix
• Limbic structures: Cingulate gyrus
• Cingulate gyrus
• Hippocampal formation
• Amygdaloid nucleus (part diencephalon
of the basal nuclei)
Mammilothalamic
• Mammillary bodies (part of tract
the hypothalamus)
• Anterior thalamic nucleus
(part of the thalamus).
• Fibre tracts: Mamillary
bodies Anterior
• Fornix Thalamic
nuclei
• mammilothalamic tract Parahippocampal
gyrus
Dr. Akram Jaffar
Dr. Akram Jaffar

25. Hippocampal formation
• Consists mainly of the hippocampus and the
parahippocampal gyrus.
• The hippocampus is a nuclear mass that lies
in the floor of the inferior horn of the lateral
ventricle.
• The axons arising from the hippocampus lie
on its surface and form the alveus.
• The fibers of the alveus form the fornix .
fornix
Inferior horn of
Lateral ventricle
hippocampus
alveus
Dr. Akram Jaffar
Parahippocampal
Coronal section gyrus
Dr. Akram Jaffar

26. Functions of the limbic system
This system is widely connected, many of its functions are not clearly understood;
nevertheless the limbic system controls:
• Emotional behavior such as fear, anger, and the emotions associated with sexual
behavior
• Recent memory
• Olfaction
Fear
Anger
Recent memory
Smell
Dr. Akram Jaffar
Emotions
Dr. Akram Jaffar

27. Features of a coronal section of the hemispheres
• Corpus callosum:
• Lies in the depth of the median sagittal Body of lateral
fissure. ventricle
• Forms a roof for the body of the lateral
Body of
ventricle. Corpus callosum
caudate
nucleus
• The body of the caudate nucleus lies in
men
the inferolateral boundary of the body of insula
puta
the lateral ventricle Globus
thalamus
pallidus
• The tail of the caudate nucleus is
tail
located at the roof of the inferior horn of
the lateral ventricle. 3rd ventricle
• Each thalamus lies on either side of the
midline forming a floor for the body of Inferior horn
the lateral ventricle
• The thalami lie on either side of the 3rd
ventricle.
body
Dr. Akram Jaffar
tail
The section passes through the body and inferior horn of the C-shaped lateral ventricle
Dr. Akram Jaffar

28. Features of a coronal section of the hemispheres
• The white matter of the internal capsule
is situated between the lentiform Body of lateral
nucleus on lateral side and the ventricle
thalamus and caudate nucleus on the
medial side. Corpus callosum
Septum
• The body of the fornix is connected to pellucidum
the undersurface of the corpus
men
callosum by the septum pellucidum.
puta
Globus
pallidus fornix
• The septum pellucidum forms a septum
between the two lateral ventricles tail
(anterior horn and body). 3rd ventricle
fornix Inferior horn
Corpus
callosum
Dr. Akram Jaffar
Septum
pellucidum
Dr. Akram Jaffar

29. The diencephalon
thalamus
• It consists of nuclear masses, mainly of the thalamus
and hypothalamus.
• Its cavity is the third ventricle.
• The thalamus:
– Is egg-shaped.
– Function :
3rd ventricle
• Mainly: a relay station of sensory impulses: It
receives sensory afferents from the spinal
cord and brain stem and projects efferents to
the primary sensory cortex.
• Is also concerned with motor control.
Interventricular
foramen
3rd ventricle
thalamus
Dr. Akram Jaffar
Dr. Akram Jaffar

30. The hypothalamus
thalamus
• Below the thalamus.
• Forms the floor and the
inferior part of the lateral
wall of the 3rd ventricle. hypothalamus
hypothalamus
Dr. Akram Jaffar
Dr. Akram Jaffar

31. The hypothalamus
• Behind the optic
Optic
chiasma the floor of the chiasma
3rd ventricle gives rise
to the stalk
infundibulum
(infundibulum) of the
hypophysis cerebri. Hypophysis
• cerebri
The mamillary bodies
lie behind. Mamillary body
Optic
chiasma
Hypophysis
cerebri
infundibulum
Dr. Akram Jaffar
Mamillary body
Dr. Akram Jaffar

32. The pituitary gland (hypophysis
cerebri)
• Endocrine gland.
• Situated in the hypophyseal fossa of
the body of the sphenoid bone.
• Is closely related to the optic chiasma:
– Tumors may produce pressure
effects on the adjacent optic
chiasma  visual defects. Hypophyseal fossa
Optic
chiasma
Hypophysis
cerebri
Dr. Akram Jaffar
Dr. Akram Jaffar

33. Functions of the hypothalamus
• Regulation of the autonomic nervous
system.
• Regulation of endocrine glands through the
hypophysis cerebri.
• Temperature regulation. thalamus
• Regulation of food and water intake.
• Control of sleep.
hypothalamus
infundibulum
Hypophysis
cerebri
Dr. Akram Jaffar
Dr. Akram Jaffar

34. Parts of the ventricular
system ventricle
Lateral
Lateral to septum
pellucidum
Interventricular
foramen
3rd ventricle
Cerebral
aqueduct
4th ventricle
Central canal
Dr. Akram Jaffar
Dr. Akram Jaffar

35. The choroid plexus
Choroid plexus
• The ventricles are lined with a single Lateral ventricle
epithelial layer called the epindyma.
• In each ventricle the lining of the cavity Choroid plexus
comes to the surface, i.e. the lining 3rd ventricle
epindyma comes in contact with the pia
mater. Choroid plexus
Lateral ventricle
• Blood capillaries invaginate at these
regions, covered by pia and epindyma
constitute the choroids plexus.
• The choroid plexuses secrete the CSF
into each ventricle.
Choroid plexus
4th ventricle
Dr. Akram Jaffar
Dr. Akram Jaffar

36. Blood barriers in the CNS Blood-CSF barrier
• Blood-CSF barrier:
– A selective barrier of
substances formed by the
tight junctions between the
choroidal epithelial cells.
• The blood brain barrier (BBB)
– A selective barrier between
the blood and the brain
tissue.
– Formed by the tight junctions
BBB
between the endothelial
lining of the capillaries.
• The function of the BBB & blood-
CSF barrier is to provide a stable
environment for the normal
function of the CNS.
Dr. Akram Jaffar
Dr. Akram Jaffar

37. CSF circulation Dural venous sinus
Arachnoid granulations
• The CSF is produced by the
choroid plexuses in all the Choroid plexus
Lateral ventricle
ventricles of the brain but
mainly in the lateral ventricles.
• Lateral ventricles  Choroid plexus
3rd ventricle
interventricular foramen  3rd
ventricle  cerebral aqueduct
 4th ventricle. Interventricular foramen
• From the 4th ventricle some CSF
passes through the central Cerebral aqueduct
canal of the spinal cord but the
majority passes through Choroid plexus
foramina in the 4th ventricle 4th ventricle
which communicate with the
subarachnoid space. Foramina in
4th ventricle
Subarachnoid space
Dr. Akram Jaffar
Dr. Akram Jaffar

38. CSF circulation
• From the subarachnoid
space the CSF finds its
way to the venous
circularion through
arachnoid villi which
project into the dural
venous sinuses
particularly the superior
sagittal sinus.
• Collections of arachnoid pits Arachnoid granulations
villi form archnoid
granulations.
• arachnoid granulations
produce pits on the inside
of the calvaria on either
side of the superior
sagittal sinus.
Dr. Akram Jaffar
Dr. Akram Jaffar