Radiological anatomy of the brain

Radiological anatomy of the brain

1. C.N.SC.N.S..
Brain AnatomyBrain Anatomy

2. Dr.Mohamed Ashraf Zaitoun, MD
Interventional Radiology Consultant, Zagazig University
Hospitals, Egypt
FINR-Switzerland
[email protected]
www.zaitounclinic.com

3. DedicationDedication
To the memory of my late father, Prof Ashraf ZaitounTo the memory of my late father, Prof Ashraf Zaitoun
Interventional
Radiology Unit,
Zagazig University,
Egypt

4. Embryology of the brainEmbryology of the brain
Prosencephalon ( forebrainProsencephalon ( forebrain ( (
Mesencephalon ( midbrainMesencephalon ( midbrain ( (
Rhombencephalon ( hindbrainRhombencephalon ( hindbrain ( (

6. Prosencephalon = ForebrainProsencephalon = Forebrain : :
Telencephalon + DiencephalonTelencephalon + Diencephalon
**TelencephalonTelencephalon : :
Cerebral cortex + Basal GangliaCerebral cortex + Basal Ganglia

7. **DiencephalonDiencephalon : :
--The diencephalon is connected above and in The diencephalon is connected above and in
front with the cerebral hemispheres; behind with front with the cerebral hemispheres; behind with
the midbrain. Its upper surface is concealed by the midbrain. Its upper surface is concealed by
the corpus callosum, and is covered by a fold of the corpus callosum, and is covered by a fold of
pia mater, named the tela chorioidea of the third pia mater, named the tela chorioidea of the third
ventricle; inferiorly it reaches to the base of the ventricle; inferiorly it reaches to the base of the
brainbrain. .

8. --It comprisesIt comprises: :
11--thalamencephalothalamencephalo : :
A)A)Thalamus Thalamus
B)B)EpithalamusEpithalamus,, consisting of the trigonum consisting of the trigonum
habenulae, the pineal body, and the posterior habenulae, the pineal body, and the posterior
commissurecommissure
2- Hypothalamus2- Hypothalamus
3- Post. Part of the 33- Post. Part of the 3
rdrd
ventricle ventricle

11. Mesencephalon = MidbrainMesencephalon = Midbrain
**Tectum + Tegmentum + Cerebral pedunclesTectum + Tegmentum + Cerebral peduncles
**Tectum ( dorsal part of midbrain) consists of sup. Colliculi ( visual Tectum ( dorsal part of midbrain) consists of sup. Colliculi ( visual
receptors ) & inf. Colliculireceptors ) & inf. Colliculi
) ) auditory receptors ) + tectal plateauditory receptors ) + tectal plate
**Tegmentum ( region ventral to ventricular systemTegmentum ( region ventral to ventricular system((
**Caudally joins the pons , rostrally joins the diencephalonCaudally joins the pons , rostrally joins the diencephalon
**Located below the cerebral cortex & above the hindrain , placing it Located below the cerebral cortex & above the hindrain , placing it
near the center of the brainnear the center of the brain

12. Rhomencephalon = HindbrainRhomencephalon = Hindbrain
**Medulla + Pons + CerebellumMedulla + Pons + Cerebellum

13. Anatomy of the brainAnatomy of the brain
Cerebral hemispheresCerebral hemispheres
Cerebral cortexCerebral cortex
White matter of the hemispheresWhite matter of the hemispheres
Basal gangliaBasal ganglia
Thalamus , hypothalamus & pineal glandThalamus , hypothalamus & pineal gland
Pituitary glandPituitary gland
Limbic lobeLimbic lobe
BrainstemBrainstem
CerebellumCerebellum
MeningesMeninges

14. Cerebral hemispheresCerebral hemispheres
--Fills the cranial cavity above the tentorium Fills the cranial cavity above the tentorium
cerebellicerebelli
--RT & LT hemispheres are connected byRT & LT hemispheres are connected by << <<
Corpus callosum , separated by median Corpus callosum , separated by median
longitudinal fissurelongitudinal fissure

15. Cerebral cortexCerebral cortex
--Lateral sulcus ( sylvian fissureLateral sulcus ( sylvian fissure ( << ( <<
Separates frontal & temporal lobesSeparates frontal & temporal lobes
--Central sulcus ( of ronaldo ) : passes upwards from the Central sulcus ( of ronaldo ) : passes upwards from the
lateral sulcus to the superior border of the hemisphere lateral sulcus to the superior border of the hemisphere
>> Separates frontal & parietal lobes>> Separates frontal & parietal lobes
--Parieto-occipital sulcusParieto-occipital sulcus << <<
Separates parietal & occipital lobesSeparates parietal & occipital lobes

19. ****N.BN.B..
--Cingulate gyrusCingulate gyrus << <<
Extends posteriorly from the frontal lobe into the Extends posteriorly from the frontal lobe into the
parietal lobeparietal lobe
--Insula ( of ReilInsula ( of Reil ( << ( <<
Is the cortex burried in the floor of the lateral Is the cortex burried in the floor of the lateral
sulcus & is crossed by branches of MCAsulcus & is crossed by branches of MCA
The parts of the frontal , parietal & temporal lobes The parts of the frontal , parietal & temporal lobes
that overlie the insula >> operculumthat overlie the insula >> operculum

20. Cingulate Gyrus
Genu of corpus
callosum
Ethmoid
air cells
Oral cavity
Splenium of
Corpus
callosum
Fourth Ventricle

22. White matter of the hemispheresWhite matter of the hemispheres
--33 types of fiberstypes of fibers : :
**Commisural fibers >> connect corresponding Commisural fibers >> connect corresponding
areas of the 2 hemispheresareas of the 2 hemispheres
**Association ( arcuate ) fibers >> connect Association ( arcuate ) fibers >> connect
different parts of the cortex of the same different parts of the cortex of the same
hemispherehemisphere
**Projection fibers >> connect the cortex to lower Projection fibers >> connect the cortex to lower
centerscenters

23. Commissural fibersCommissural fibers : :
11--Corpus callosumCorpus callosum
Rostrum >> 1Rostrum >> 1
stst
part which extends anteriorly from part which extends anteriorly from
the ant. Commisurethe ant. Commisure
Genu >> most ant. PartGenu >> most ant. Part
Trunk ( body ) >> from genu ant. To splenium Trunk ( body ) >> from genu ant. To splenium
postpost..
Splenium >> thickened post. partSplenium >> thickened post. part

24. ****N.BN.B..
--Fibers from the genu that arch forward to the Fibers from the genu that arch forward to the
frontal cortex on each side >> forceps minorfrontal cortex on each side >> forceps minor
--Fibers from the splenium passing post. To each Fibers from the splenium passing post. To each
occipital cortex >> forceps majoroccipital cortex >> forceps major
--Fibers extending laterally from the body of the Fibers extending laterally from the body of the
CC >> tapetum ( form part of the roof & lateral CC >> tapetum ( form part of the roof & lateral
wall of the lateral ventriclewall of the lateral ventricle ( (

35. Projection fibersProjection fibers
--These fibers join the cerebral cortex to lower These fibers join the cerebral cortex to lower
centers >> internal capsulecenters >> internal capsule
--Ant. Limb between caudate & lentifomAnt. Limb between caudate & lentifom
--Post. Limb between thalamus & lentiformPost. Limb between thalamus & lentiform
--Both limbs meet at right angle >> genuBoth limbs meet at right angle >> genu

37. Basal gangliaBasal ganglia
--Corpus striatum ( caudate & lentiformCorpus striatum ( caudate & lentiform ( (
--Amygdaloid bodyAmygdaloid body
--ClaustrumClaustrum
**Caudate nucleusCaudate nucleus : :
--Head , body & tail , its long & thin tail ends in the amygdaloid Head , body & tail , its long & thin tail ends in the amygdaloid
nucleusnucleus
--Lies in the concavity of the lateral VLies in the concavity of the lateral V
--Its head projects in the floor of the ant. Horn & its body lies along Its head projects in the floor of the ant. Horn & its body lies along
the body of the lat. V , its tail lies in the roof of the inferior horn the body of the lat. V , its tail lies in the roof of the inferior horn
of this Vof this V

38. **LentiformLentiform : :
--Made up of a larger lateral putamen & a smaller Made up of a larger lateral putamen & a smaller
medial globus pallidusmedial globus pallidus
--Separated from head of caudate ant. & from the Separated from head of caudate ant. & from the
thalamus post. By the internal capsulethalamus post. By the internal capsule
--A thin layer of white matter on its lateral surface A thin layer of white matter on its lateral surface
>> external capsule>> external capsule

39. **ClaustrumClaustrum : :
--Thin sheet of grey matter lies between the Thin sheet of grey matter lies between the
putamen & the insulaputamen & the insula
--It is separated medially from the putamen by the It is separated medially from the putamen by the
external capsule & bounded laterally by a thin external capsule & bounded laterally by a thin
sheet of white mattersheet of white matter
) ) the extreme capsule ) just deep to the insulathe extreme capsule ) just deep to the insula

41. Thalamus , hypothalamus & pineal glandThalamus , hypothalamus & pineal gland
--The structures around the 3The structures around the 3
rdrd
ventricle include : thalamus , hypothalamus & ventricle include : thalamus , hypothalamus &
pineal gland , together with the habenula these form the diencephalonpineal gland , together with the habenula these form the diencephalon
**ThalamusThalamus : :
--RelationsRelations << << ……
--The superior part of the thalamus forms part of the floor of the lateral VThe superior part of the thalamus forms part of the floor of the lateral V
--The thalamus is attached in 60 % of cases to the thalamus of the other side by The thalamus is attached in 60 % of cases to the thalamus of the other side by
the interthalamic adhesions or massa intermediathe interthalamic adhesions or massa intermedia
--Medial & lateral swellings on the postero-inferior aspect of the thalamus are Medial & lateral swellings on the postero-inferior aspect of the thalamus are
called the geniculate bodies , the medial geniculate body is attached to the inf. called the geniculate bodies , the medial geniculate body is attached to the inf.
Colliculus & the lateral geniculate body is attached to sup. ColliculusColliculus & the lateral geniculate body is attached to sup. Colliculus
--Blood supply >> thalamo-striate branches of PCABlood supply >> thalamo-striate branches of PCA

43. **HypothalamusHypothalamus : :
--Forms the floor of the 3Forms the floor of the 3
rdrd
V V
--It includesIt includes : :
****Optic chiasmOptic chiasm
****Tuber cinereum >> a sheet of gray matter between the optic chiasm & the Tuber cinereum >> a sheet of gray matter between the optic chiasm & the
mamillary bodiesmamillary bodies
****Infundibular stalk >> leading down to the post. Lobe of the pituitary glandInfundibular stalk >> leading down to the post. Lobe of the pituitary gland
****Mamillary bodies >> round masses in which the columns of the fornix ( vida Mamillary bodies >> round masses in which the columns of the fornix ( vida
infra ) endinfra ) end
****Post. Perforated substancePost. Perforated substance
--Blood supply >> branches of ACA , PCA & post. Communicating arteries , Blood supply >> branches of ACA , PCA & post. Communicating arteries ,
drained by thalamo-striate veinsdrained by thalamo-striate veins

47. **Pineal glandPineal gland : :
--Lies between the post. Ends of the thalami & between Lies between the post. Ends of the thalami & between
the splenium above & the sup. Colliculi belowthe splenium above & the sup. Colliculi below
--It is separated from the splenium by the cerebral veins , it It is separated from the splenium by the cerebral veins , it
lies within 3 mm of the midlinelies within 3 mm of the midline
--The pineal stalk has superior & inferior laminae , the sup. The pineal stalk has superior & inferior laminae , the sup.
Is formed by the habenular commisure & the inf. Is formed by the habenular commisure & the inf.
Contains the post. Commisure , between these lamina is Contains the post. Commisure , between these lamina is
the post. Recess of the 3the post. Recess of the 3
rdrd
ventricle ventricle

49. A. Genu of the Corpus Callosum
B. Anterior Horn of the Lateral
Ventricle
C. Internal Capsule
D. Thalamus
E. Pineal Gland
F. Choroid Plexus
G. Straight Sinus

50. Pituitary gland ( hypophysis cerebriPituitary gland ( hypophysis cerebri ( (
--Site >> pituitary ( hypophyseal ) fossaSite >> pituitary ( hypophyseal ) fossa
--Measuring >> 12 mm in transverse diamMeasuring >> 12 mm in transverse diam..
88 mm in AP diametermm in AP diameter
99 mm in heightmm in height

51. --Formed ofFormed of : :
**Infundibulum ( stalk ) >> the connection between the hypothalamus & post. Infundibulum ( stalk ) >> the connection between the hypothalamus & post.
pituitarypituitary
**Ant. LobeAnt. Lobe << <<
--55 times larger than the post. Lobetimes larger than the post. Lobe
--Developed from the rathkeDeveloped from the rathke’’s pouch in the roof of the primitve mouths pouch in the roof of the primitve mouth
--Craniopharyngioma is a tumor from the remnant of its epitheliumCraniopharyngioma is a tumor from the remnant of its epithelium
--Ant. Lobe is adherent to the post. Lobe by narrow zone called Pars intermedia , Ant. Lobe is adherent to the post. Lobe by narrow zone called Pars intermedia ,
actually it is a part of the anterior lobeactually it is a part of the anterior lobe
**Post. LobePost. Lobe << <<
--Much smaller than the ant. LobeMuch smaller than the ant. Lobe
--Developed from the nerve fibers whose cell bodies lie in the hypothalamusDeveloped from the nerve fibers whose cell bodies lie in the hypothalamus

52. --RelationsRelations : :
**Above >> Diaphragma sella ( dura matterAbove >> Diaphragma sella ( dura matter ( (
& & above this the suprasellar cistern with optic chiasm anteriorly & above this the suprasellar cistern with optic chiasm anteriorly &
circle of williscircle of willis
**Below >> the body of sphenoid & sphenoid sinusBelow >> the body of sphenoid & sphenoid sinus
**Laterally >> Dura matterLaterally >> Dura matter
Cavernous sinus & its contentCavernous sinus & its content : :
ICA ,, 3ICA ,, 3
rdrd
, 4 , 4
thth
cranial nerves , ophthalmic division of 5 cranial nerves , ophthalmic division of 5
thth
cranial cranial
nerve & 6nerve & 6
thth
cranial nerve cranial nerve
-- -- N.B. >> The cavernous sinuses are united by the intercavernous N.B. >> The cavernous sinuses are united by the intercavernous
sinuses which surround the pituitary gland ant. , post. & infsinuses which surround the pituitary gland ant. , post. & inf..

53. --Sella turicicaSella turicica : :
**It is a superior saddle shaped formation on the intracranial aspect of the body of It is a superior saddle shaped formation on the intracranial aspect of the body of
sphenoid bone containing pituitary glandsphenoid bone containing pituitary gland
**Boundaries : ant. >> ant. Clinoid processBoundaries : ant. >> ant. Clinoid process
post. >> post. Clinoid processpost. >> post. Clinoid process
lat. >> cavernous sinuslat. >> cavernous sinus
**AnatomyAnatomy : :
The seat of the saddle is known as the hypophyseal fossa, which holds the The seat of the saddle is known as the hypophyseal fossa, which holds the
pituitary gland. The hypophyseal fossa is located in a depression in the body pituitary gland. The hypophyseal fossa is located in a depression in the body
of the sphenoid bone. Located anteriorly to the hypophyseal fossa is the of the sphenoid bone. Located anteriorly to the hypophyseal fossa is the
tuberculum sellae ( optic foramen lies on either sides of ittuberculum sellae ( optic foramen lies on either sides of it ( (
Completing the formation of the saddle posteriorly is the dorsum sellae which is Completing the formation of the saddle posteriorly is the dorsum sellae which is
continuous with the clivus, inferoposteriorly. The dorsum sellae is terminated continuous with the clivus, inferoposteriorly. The dorsum sellae is terminated
laterally by the posterior clinoid processlaterally by the posterior clinoid process..

58. --Arterial supplyArterial supply : :
ICAICA
**Sup. Hypophyseal arteriesSup. Hypophyseal arteries
**Inf. Hypophyseal arteriesInf. Hypophyseal arteries
--Venous drainageVenous drainage : :
To cavernous & inter-cavernosal sinusesTo cavernous & inter-cavernosal sinuses

59. --Radiological featuresRadiological features : :
11--Skull radiographySkull radiography << <<
Lateral viewLateral view
22--CT & MRICT & MRI << <<
**Best on sagittal & coronalBest on sagittal & coronal
**Post. Pituitary appears high signal intensity on unenhanced T1 WIsPost. Pituitary appears high signal intensity on unenhanced T1 WIs
**Dura above the sella must be horizontal not convexDura above the sella must be horizontal not convex
--Infundibulum diameter should be not bigger than the adjacent basilar arteryInfundibulum diameter should be not bigger than the adjacent basilar artery
**Sella itself is delineated bySella itself is delineated by : :
Signal void of the bony cortexSignal void of the bony cortex
High intensity signal of marrow in the clivusHigh intensity signal of marrow in the clivus
**Optic nerves,chiasm & ICA vessels above & sphenoid sinus below seen clearly Optic nerves,chiasm & ICA vessels above & sphenoid sinus below seen clearly
on coronal sectionson coronal sections

65. Limbic lobeLimbic lobe
--This is not an anatomical lobe as such but functionally related This is not an anatomical lobe as such but functionally related
structures that surrounds the corpus callosum on the medial structures that surrounds the corpus callosum on the medial
surface of the cerebral hemispheresurface of the cerebral hemisphere
--It includesIt includes : :
Cingulate gyrusCingulate gyrus
Splenial gyrusSplenial gyrus
Parahippocampal gyrusParahippocampal gyrus
HippocampusHippocampus
Dentate gyrusDentate gyrus
fornixfornix

67. --The cingulate gyrus curves around the genu & body of The cingulate gyrus curves around the genu & body of
CC and continues around the splenium as splenial gyrus CC and continues around the splenium as splenial gyrus
>> this in turn is continuous with dentate gyrus & >> this in turn is continuous with dentate gyrus &
hippocampushippocampus
--Hippocampus >> is a curved elevation in the floor of the Hippocampus >> is a curved elevation in the floor of the
inf. Horn of the lateral ventricleinf. Horn of the lateral ventricle
--Fornix >> is an efferent pathway from the hippocampus Fornix >> is an efferent pathway from the hippocampus
to the mamillary bodiesto the mamillary bodies

69. BrainstemBrainstem
--Connects the cerebral hemispheres to the spinal Connects the cerebral hemispheres to the spinal
cord , extends from just above the tentorial cord , extends from just above the tentorial
hiatus to just below the foramen magnumhiatus to just below the foramen magnum
--It is bounded ant. By the clivus-basisphenoid It is bounded ant. By the clivus-basisphenoid
above & the basiocciput belowabove & the basiocciput below
--has three parts : midbrain , pons & medullahas three parts : midbrain , pons & medulla

71. **MidbrainMidbrain : :
--Anteriorly two cerebral peduncles are seen separated the Anteriorly two cerebral peduncles are seen separated the
interpeduncular fossainterpeduncular fossa
--The post. Surface of the midbrain presents four rounded The post. Surface of the midbrain presents four rounded
prominences ( the corpora quadrigemina or the sup. & prominences ( the corpora quadrigemina or the sup. &
inf. Colliculiinf. Colliculi ( , ( ,
each sup. Colliculus >> lateral geniculate body of the each sup. Colliculus >> lateral geniculate body of the
optic tractoptic tract
Each inf. Colliculus >> medial geniculate body of the Each inf. Colliculus >> medial geniculate body of the
auditory systemauditory system

72. --Cerebral peduncles have a ventral part , the crus Cerebral peduncles have a ventral part , the crus
cerebri and a dorsal part , the tegmentum , these cerebri and a dorsal part , the tegmentum , these
are separated by the substantia nigraare separated by the substantia nigra
--The part of the midbrain posterior to the The part of the midbrain posterior to the
aqueduct is called the tectum or quadrigeminal aqueduct is called the tectum or quadrigeminal
plateplate
--Cranial nerves >> 3Cranial nerves >> 3
rdrd
& 4 & 4
thth
cranial nerves cranial nerves
--Blood supply >> Sup. cerebellarBlood supply >> Sup. cerebellar

74. **PonsPons : :
--A shallow groove is seen in the midline , the basilar artery A shallow groove is seen in the midline , the basilar artery
may lie in this groove , but often lies lateral to itmay lie in this groove , but often lies lateral to it
--The post. Surface of the pons forms the upper part of The post. Surface of the pons forms the upper part of
the floor of the 4the floor of the 4
thth
ventricle ventricle
--Cranial nerves >> 5Cranial nerves >> 5
thth
& 6 & 6
thth
cranial nerves cranial nerves
77
thth
& 8 & 8
thth
cranial nerves emerges at the junction with the cranial nerves emerges at the junction with the
medulla laterally >> CPA ( cerebello-pontine anglemedulla laterally >> CPA ( cerebello-pontine angle ( (
--Blood supply >> pontine branches of the basilar ABlood supply >> pontine branches of the basilar A

76. **Medulla oblongataMedulla oblongata : :
--Ant. The ventral median fissure is deep in its superior part , a ridge Ant. The ventral median fissure is deep in its superior part , a ridge
on each side of this fissure is formed by the pyramidal fibers and on each side of this fissure is formed by the pyramidal fibers and
is called the pyramid , lateral to the pyramid in the upper medulla is called the pyramid , lateral to the pyramid in the upper medulla
is an oval bulge called the olive , lateral to the olive lies the inf. is an oval bulge called the olive , lateral to the olive lies the inf.
Cerebellar peduncle joining the medulla to the cerebellumCerebellar peduncle joining the medulla to the cerebellum
--Post. The upper part of the medulla is open in the floor of the 4Post. The upper part of the medulla is open in the floor of the 4
thth

ventricleventricle
--Cranial nerves >> 9Cranial nerves >> 9
thth
, 10 , 10
thth
, 11 , 11
thth
& 12 & 12
thth
cranial nerves cranial nerves
--blood supply >> ant. Part : vertebral & basilarblood supply >> ant. Part : vertebral & basilar
post. Part : PICApost. Part : PICA

78. CerebellumCerebellum
--The cerebellum lies in the post. Fossa , it is separated from the The cerebellum lies in the post. Fossa , it is separated from the
occipital lobe by the tentorium & from the the pons and occipital lobe by the tentorium & from the the pons and
midbrain by the 4midbrain by the 4
thth
V V
--It is connected to the brainstem by 3 pairs of cerebellar pedunclesIt is connected to the brainstem by 3 pairs of cerebellar peduncles : :
Sup. Cerebellar peduncles to the midbrainSup. Cerebellar peduncles to the midbrain
Middle Cerebellar peduncles to the ponsMiddle Cerebellar peduncles to the pons
Inf. Cerebellar peduncles to the medullaInf. Cerebellar peduncles to the medulla
--There are 2 hemispheres with the midline vermis betweenThere are 2 hemispheres with the midline vermis between

79. --The hemispheres >> on each side below the middle cerebellar The hemispheres >> on each side below the middle cerebellar
peduncle is the folliculus , the tonsils are the most ant. Inf. Part peduncle is the folliculus , the tonsils are the most ant. Inf. Part
of the hemispheres and lie close to the midlineof the hemispheres and lie close to the midline
--The vermis >> is the narrow midline portion of the cerebllum , The vermis >> is the narrow midline portion of the cerebllum ,
sup. There is a low median elevation not clearly separated from sup. There is a low median elevation not clearly separated from
the hemispheres , however inf. The vermis is quite separate & the hemispheres , however inf. The vermis is quite separate &
lies in a deep cleft called the vallecula , the most ant. Part of the lies in a deep cleft called the vallecula , the most ant. Part of the
sup. Vermis is the lingula , which lies on the sup. Medullary sup. Vermis is the lingula , which lies on the sup. Medullary
vilumvilum
) ) a thin sheet of white matter between the sup. Cerebellar peduncles a thin sheet of white matter between the sup. Cerebellar peduncles
) , the most ant. Part of the inf. Vermis is the nodule) , the most ant. Part of the inf. Vermis is the nodule

80. --SubdivisionsSubdivisions : :
Ant. LobeAnt. Lobe
Post. LobePost. Lobe
Flocculonodular lobeFlocculonodular lobe
--Arterial supplyArterial supply : :
PICA from the vertebralPICA from the vertebral
AICA from the basilarAICA from the basilar
Sup. Cerebellar arteries from basilar ASup. Cerebellar arteries from basilar A
--Venous drainageVenous drainage : :
Precentral cerebellar vein & the sup. Vermian vein drain to the great cerebral veinPrecentral cerebellar vein & the sup. Vermian vein drain to the great cerebral vein
Remaining of the cerebellar vein >> nearby dural sinusesRemaining of the cerebellar vein >> nearby dural sinuses
) ) straight , transverse , inf. Petrosal , sigmoid & occipital sinusesstraight , transverse , inf. Petrosal , sigmoid & occipital sinuses ( (
N.B. >> the normal floculus enhances more than the rest of the cerebellum , shouldnot N.B. >> the normal floculus enhances more than the rest of the cerebellum , shouldnot
be mistaken for a more ant. Located acoustic neuromabe mistaken for a more ant. Located acoustic neuroma

81. A. Frontal Lobe
B. Frontal Bone )Superior
Surface of Orbital Part(
C. Dorsum Sellae
D. Basilar Artery
E. Temporal Lobe
F. Mastoid Air Cells
G. Cerebellar Hemisphere

82. A. Falx Cerebri
B. Frontal Lobe
C. Anterior Horn of
Lateral Ventricle
D. Third Ventricle
E. Quadrigeminal
Plate Cistern
F. Cerebellum

83. MeningesMeninges
--Three layers of meninges cover the brain & spinal cord >> dura , Three layers of meninges cover the brain & spinal cord >> dura ,
arachnoid & piaarachnoid & pia
**Dura materDura mater : :
--Two layers , outer layer which is the periosteum of the inner aspect Two layers , outer layer which is the periosteum of the inner aspect
of the skull , the inner layer is the dura mater properof the skull , the inner layer is the dura mater proper
--Falx cerebri >> sickle-shaped dural septum in the median sagittal Falx cerebri >> sickle-shaped dural septum in the median sagittal
plane attached to the crista galli in the midline of the floor of the plane attached to the crista galli in the midline of the floor of the
ant. Cranial fossa & along the midline of the inner aspect of the ant. Cranial fossa & along the midline of the inner aspect of the
vault of the skull to the margins of the SSSvault of the skull to the margins of the SSS

84. --Diaphragma sellae >> is a horizontal fold of dura that Diaphragma sellae >> is a horizontal fold of dura that
almost completely covers the pituitary fossa , with a almost completely covers the pituitary fossa , with a
small opening for the pituitary stalksmall opening for the pituitary stalk
--Tentorium cerebelli >> is a horizontal septum of dura Tentorium cerebelli >> is a horizontal septum of dura
mater that separates the occipital lobes from the mater that separates the occipital lobes from the
superior surface of the cerebellumsuperior surface of the cerebellum
--Falx cerebelli >> is a low elevation of dura that projects Falx cerebelli >> is a low elevation of dura that projects
a small distance into the cerebellar interhemispheric a small distance into the cerebellar interhemispheric
fissurefissure

85. **Arachnoid materArachnoid mater : :
--Delicate membrane which is impermeable to CSF , it Delicate membrane which is impermeable to CSF , it
lines the dura matter separated from it only by a thin lines the dura matter separated from it only by a thin
layer of lymph in the subdural ( potential spacelayer of lymph in the subdural ( potential space ( (
--It is separated from the pia mater by the subarachnoid It is separated from the pia mater by the subarachnoid
space , which contains the CSFspace , which contains the CSF
--Arachnoid mater herniates through holes in the dura into Arachnoid mater herniates through holes in the dura into
the venous sinuses & venous lakes as arachnoid villi >> the venous sinuses & venous lakes as arachnoid villi >>
CSF absorptionCSF absorption

86. **Pia materPia mater : :
--Closely adherent to the brain surfaceClosely adherent to the brain surface
--It invaginates with with the choroid vessels into It invaginates with with the choroid vessels into
the ventricles , & the layer of pia mater & the ventricles , & the layer of pia mater &
ependyma together thus formed over these ependyma together thus formed over these
vessels is called >> tela choroidea of the vessels is called >> tela choroidea of the
ventriclesventricles

88. --Arterial supply of the meningesArterial supply of the meninges : :
**MMA ( middle meningeal arteryMMA ( middle meningeal artery ( (
branch of the maxillary artery that enters the the cranium through foramen branch of the maxillary artery that enters the the cranium through foramen
spinosum , it passes laterally in the floor of the middle cranial fossa , then spinosum , it passes laterally in the floor of the middle cranial fossa , then
superiorly & anteriorly along the greater wing of sphenoid , where it divides superiorly & anteriorly along the greater wing of sphenoid , where it divides
into ant. & post. Branchesinto ant. & post. Branches
**Additional supplyAdditional supply << <<
--Ant. Cranial fossa : meningeal branches of ophthalmic & ant. & post. Ethmoid Ant. Cranial fossa : meningeal branches of ophthalmic & ant. & post. Ethmoid
arteriesarteries
--Cavernous sinus : meningeal branches of carotid artery & the accessory Cavernous sinus : meningeal branches of carotid artery & the accessory
meningeal arterymeningeal artery
--Post. Fossa : meningeal branches of vertebral arteryPost. Fossa : meningeal branches of vertebral artery
--Nerve supply : 5Nerve supply : 5
thth
, 9 , 9
thth
& 10 & 10
thth
cranial nerves , with the dura around the foramen cranial nerves , with the dura around the foramen
magnum being innervated by C1-3 nervesmagnum being innervated by C1-3 nerves

90. --Radiological featuresRadiological features : :
**Extradural hematomaExtradural hematoma
--Occurs when a vessel in the extradural space between dura and bone is torn by Occurs when a vessel in the extradural space between dura and bone is torn by
trauma >> MMAtrauma >> MMA
**Subdural hematomaSubdural hematoma
--Also due to traumatic bleed in space between dura & arachnoid >> bridging Also due to traumatic bleed in space between dura & arachnoid >> bridging
veinsveins
--Subdural hematoma can extend into interhemispheric fissure & root of sylvian Subdural hematoma can extend into interhemispheric fissure & root of sylvian
fissure on the brain surfacefissure on the brain surface
**Subarachnoid hemorrhageSubarachnoid hemorrhage
--In the subarachnoid space between the arachnoid & pia mater from In the subarachnoid space between the arachnoid & pia mater from
spontaneous or traumatic rupture of an arteryspontaneous or traumatic rupture of an artery
--Subarachnoid blood can then be seen in the cisterns & extending into sulci & Subarachnoid blood can then be seen in the cisterns & extending into sulci &
fissures on the brain surface close to the site of bleedingfissures on the brain surface close to the site of bleeding

94. **Skull radiographSkull radiograph : :
--Dural calcification is common in older subjectsDural calcification is common in older subjects
--Calcification of falx cerebri or of the tentorium can be seen in OF or FO viewsCalcification of falx cerebri or of the tentorium can be seen in OF or FO views
**CT & MRICT & MRI : :
--Above the level of the petrous temporal bone the cerebral hemispheres are Above the level of the petrous temporal bone the cerebral hemispheres are
separated from the cerebellum by the tentoriumseparated from the cerebellum by the tentorium
--Best seen on contrast enhanced scans as it contains blood vesselsBest seen on contrast enhanced scans as it contains blood vessels
--The tentorium is seen as high attenuation linear structure extending laterally The tentorium is seen as high attenuation linear structure extending laterally
from the midbrain to the inner table of the skullfrom the midbrain to the inner table of the skull
--The falx ccerebri is seen on higher cuts ant. & post. Extending into the The falx ccerebri is seen on higher cuts ant. & post. Extending into the
interhemispheric fissure almost to the corpus callosuminterhemispheric fissure almost to the corpus callosum