ANATOMY OF THE CEREBRAL VENTRICLES Francois du Toit Diagnostic Radiology Kimberley Hospital.

ANATOMY OF THE CEREBRAL VENTRICLES

Francois du Toit

Diagnostic Radiology

Kimberley Hospital

The Cerebral Ventricles

Fluid filled (CSF) spaces within the brain

2 Lateral ventricles in each hemisphere

3rd ventricle, Cerebral Aquaduct, 4th ventricle midline

Ependyma (thin epithelial membrane lining)

The Cerebral Ventricles

THE LATERAL VENTRICLE

The Lateral Ventricles

• Lies within each cerebral hemisphere:• Frontal Horn (anterior)• Body (atrium)• Temporal Horn (inferior)• Occipital Horn (posterior)

• Interventricular Foramen (of Monroe)• connects each lateral ventricle with the 3rd ventricle• at junction of anterior horn & body

FRONTAL HORN


Frontal (anterior) Horn

Extends into frontal lobe

Roof & Ant extremity formed by: Corpus Collosum (Rostrum & Genu) Tapetum

Floor & Lateral Wall Caudate Nucleus

Medial Wall Septum Pellucidum

Roof / Anterior Border

Floor of Anterior Horn

Medial Wall of Anterior Horn

BODY (atrium)


Body of Lateral Ventricle

In Parietal Lobe Roof & Lateral Wall

Corpus Callosum Tapetal Fibres

Medial wall Septum Pellucidum

Floor (medial) Thalamus

Floor (lateral) Body of Caudate Nucleus

Thalamostriate vein in between Body of Fornix lies above the thalamus Between the fornix and the thalamus

Choroid plexus lies invaginated into the cavity of the ventricle in a groove - the choroidal fissure

Roof / Anterior Border


In Parietal Lobe Roof & Lat








Caudate Nucleus

Thalamus


In Parietal Lobe Roof & Lat







Thalamus

Body of Fornix

Choroid Plexus


TEMPORAL HORN (inferior)


Temporal (inferior) Horn

Extends anteriorly into Temporal Lobe Lateral wall

Fibres of Tapetum

Roof Tail of Caudate Nucleus

Floor Hippocampus pes hippocampi anterior crus of the fornix arising from this

Temporal Horn of Lateral Ventricle

Tapetum

Temporal (inferior) Horn

Extends anteriorly into Temporal Lobe Lateral wall

Fibres of Tapetum

Roof Tail of Caudate Nucleus

Floor Hippocampus pes hippocampi anterior crus of the fornix arising from this

Crus of Fornix

Hippocampus

Pes

OCCIPITAL HORN (Posterior)


Occipital (posterior) Horn

Posterior Extension of Lateral ventricle Extends into Occipital Lobe Arises from trigone of lateral ventricle

posterior convexity of the body of the lateral ventricle

May be absent / poorly developed / extend the full depth 12% bilaterally well developed

THE CHOROID PLEXUS

Choroid Plexus of Lateral Ventricle

Responsible for most of the production of CSF Extends from Inferior horn, through body, to interventricular

foramen NO CHOROID PLEXUS in Occipital & Frontal Horn Continuous with Choroid Plexus of 3rd ventricle Invaginated into Lateral Ventricles medially

(Choroidal Fissure)


Blood supply: Ant Choroidal a. (Branch of ICA) Post Choroidal a. (Branch of post Cerebral a.)

Venous drainage: Sup Choroidal vein (begins at inferior horn and

passes anteriorly to IV foramen) Joins Sup Thalamostriate v. to form Internal Cerebral

vein at IV foramen

3rd Ventricle

Slit-like space between Thalami Width = 2-10mm (increasing with age) Thin anterior wall – Lamina Terminalis

between ant commissure (above) to optic chiasm (below)

Extension inferiorly into optic chiasm = supraoptic recess

Floor = Structures of hypothalamus including pituitary whose hollow stalk is the infundibular recess of the ventricle

Fold of Pia containing CP = Tela Choroidea Narrow Anterior Apex at IV Foramen Wider Posterior

If Fluid accumulates = Cavum Velum Interpositum

Third Ventricle

Thalamus

3rd Ventricle







Lamina Terminalis

Optic Chiasm

Anterior Commisure

3rd Ventricle







Cavum Velum Interpositum

3rd Ventricle

Posteriorly - extends as small pineal recess into pineal stalk, and above this into suprapineal recess

Roof - anteriorly, the anterior commissure, column of fornix and IV foramen.Behind this the body of the fornix, with Choroid plexus invaginating below the fornix

60% of people - thalami connected across the ventricle via massa intermedia (non-neural connection)

Fornix

Ant Commisure

Choroid Plexus

3rd Ventricle

Posteriorly - extends as small pineal recess into pineal stalk, and above this into suprapineal recess

Roof - anteriorly, the anterior commissure, column of fornix and IV foramen.Behind this the body of the fornix, with Choroid plexus invaginating below the fornix

60% of people - thalami connected across the ventricle via massa intermedia (non-neural connection)

THE CEREBRAL AQUEDUCT

Cerebral Aquaduct

Narrow channel connecting post end of 3rd ventricle with sup end of 4th ventricle

1.5cm in length. 1-2mm in diameter

Passes through Brainstem with Tectum posterior to it and Tegmentum and Cerebral Peduncles anteriorly

Nuclei of CN III,IV,V surround aqueduct and are called the periaqueductal grey matter

Cerebral Aqueduct

4th Ventricle

Aqueduct widens Posterior to the Pons Narrows again in inferior part of medulla as

central canal of the medulla & of spinal cord Floor = diamond shaped (rhomboid fossa)

Formed by post surface of pons and upper part of medulla Roof

SUPERIORsuperior cerebellar peduncle with sup medullary velum betweenINFERIORinf cerebellar peduncle and the inf medullary velum

Over these lies the cerebellum

4th Ventricle

4th Ventricle

Aqueduct widens Posterior to the Pons Narrows again in inferior part of medulla as

central canal of the medulla & of spinal cord Floor = diamond shaped (rhomboid fossa)

Formed by post surface of pons and upper part of medulla Roof

SUPERIORsuperior cerebellar peduncle with sup medullary velum betweenINFERIORinf cerebellar peduncle and the inf medullary velum

Over these lies the cerebellum

4th Ventricle Roof

Foramina

4th Ventricle

Foramina of 4th Ventricle

3 Openings in lower part of roof one median aperture (of Magendie)

large opening in inf medullary velum beneath the cerebellum, which communicates with the cisterna magna

two lateral apertures (of Luschka) at apex of lateral recesses of the ventricle open anteriorly just behind CN VIII into the pontine

cistern Choroid plexus invaginates the lower part of its roof and is

supplied by inferior cerebellar a.

Foramen of Magendie

4th Ventricle Foramina






Foramen of Luschka

4th Ventricle Foramina






Choroid Plexus of 4th Ventricle

CSF PRODUCTION & FLOW

CSF Production & Flow

Total Volume of CSF = 150ml (25ml is within and around the spinal cord)

Produced at 0.4ml/min

Production independent of CSF pressure

Principally produced by Choroid Plexus of lateral ventricles

CSF Flow

Flows through Interventricular foramen into 3rd ventricle Via Cerebral Aqueduct to 4th Ventricle Via Midline Aperture (of Magendie) into Cisterna Magna Via Lateral Apertures into Pontine Cistern From Basal Cisterns

some fluid flows down and bathes the spinal cord

The Remainder passes upward through tentorial hiatus and diffuses over surface of

the cerebral hemispheres

CSF Flow

Into 3rd Ventricle (Monroe)

Into 4th Venticle (Cerebral Aqueduct)

Into Cisterna Magna (Magendie)

Down to Spinal Cord

Upwards over Cerebral Hemispheres

CSF Absorbtion

CSF is absorbed through the Arachnoid Villi herniations of arachnoid through holes in the dura into

venous sinuses most numerous in sup sagittal sinus discrete in children with age they aggregate into visible clumps called

arachnoid granulations these indent the inner table of the skull beside the dural

venous sinuses

Arachnoid Villi

CSF Absorbtion

1/3 CSF absorbed along similar spinal villi OR

escapes along nerve sheaths into perineural lymphatics

This absorption is passive and dependent on hydrostatic pressure differences

ANATOMICAL VARIANTS


Fluid Collects in Tela Choroidea Narrow apex anterior Wider Posteriorly

Cavum Septum Pellucidum

Two potential spaces between leaflets of Septum Pellucidum ANTERIOR Cavum Septum Pellucidum POSTERIOR Cavum Vergae

Obliterate Postero-anteriorly during development CSP present in 100% of fetusses 85% Obliterate by 3-6months Absent CSP in fetus associated with significant CNS

abnormalities

Cavum Vergae

Seperation of the leaflets of septum pellucidum Posterior extension to the splenium of corpus

collosum Because of ordered obliteration – CSP almost always

accompanies a Cavum Vergae

Cavum Vergae

Cavum Septum Pellucid

umCavum Vergae

References

Anatomy for Diagnostic Imaging, 3rd EditionStephanie Ryan, Michelle McNicholas, Stephen Eustace

Atlas of Human Anatomy, 2nd EditionFrank H. Netter

http://www.imaios.com/

http://www.radiopaedia.org/

ANATOMY OF THE CEREBRAL VENTRICLES Francois du Toit Diagnostic Radiology Kimberley Hospital.

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