Ventricles of Brain-Lateral, Third and Fourth ventricles

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Ventricles of Brain
Introduction: Cavities in the brain containing cerebrospinal fluid is known as Ventricles.
Cavities of Brain:
Cavities of Cerebrum: Lateral Ventricles (Right and Left Lateral ventricle in right and left cerebral
hemispheres.
Cavity of Diencepahlon: Third Ventricle.
Cavity of Midbrain: Cerebral aqueduct connecting third ventricle with fourth ventricle.
Cavity of Hindbrain (Pons-Medulla oblongata and Cerebellum): Fourth ventricle.
Lateral Ventricle (Cavity of cerebrum)
(*****Most Important Short Note)

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FEATURES SEEN IN LATERAL VENTRICLE
 Cavity of Telencephalon-cerebrum
 Shape: “C” shaped
 Parts with features seen in each part:
 Anterior Horn: Located in frontal lobe.
 Features and boundaries:
 Floor contains head of caudate nucleus.
 Anterior wall, floor and roof formed by corpus callosum.
 Medial wall by septum pellucidum.
 Lateral wall and floor is sloping and formed by head of caudate nucleus.
 Central Part: Located in parietal lobe.
 Features and boundaries:
 Floor contain: Body of caudate nucleus and thalamus.
 Roof by trunk of corpus callosum.

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 Medial wall by septum pellucidum.
 Lateral wall and floor is sloping and formed by head of caudate nucleus.
 Posterior horn: Located in occipital lobe. Small and inconstant.
 Features: If this horn is present it shows following features:
 Bulb of posterior horn raised by forceps major.
 Calcar avis raised by calcarine sulcus is seen into it.
 Inferior horn: Located in temporal lobe.
 Features seen:
 Features in the floor: Hippocampus and pes hippocampi seen its floor covered
by alveus and fimbria.
 Roof formed by tail of caudate nucleus and amygdaloid body.
 Communication with third ventricle by interventricular foramen of Monroe
 Function: Contain choroid plexus responsible for secretion of cerebrospinal fluid.
 Applied Anatomy: Blockage of interventricular foramen leads to dilatation of lateral ventricle.
This condition is known as Hydrocephalus. It leads to mental retardation.
Third Ventricle (Cavity of Diencephalon)
(***Important Short Note)
 Cavity of diencephalon located between diencephalon i.e. between two thalami.
 Shape: Slit like
 Anterior wall: Lamina terminalis, anterior commissure and anterior column of fornix.
 Posterior wall: Pineal gland with pineal recess and habenular and posterior commissure.
 Lateral wall: Thalamus and Hypothalamus separated by hypothalamic sulcus
 Superior wall (Roof): Ependyma, tela choroidea of third ventricle, internal cerebral veins,
fornix and corpus callosum.
 Inferior wall (Floor): Optic chiasma, tuber cinerium, infundibulum with its recess, mammilary
bodies, tegmentum of cerebral peduncles of midbrain.

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 Recesses:
 Pineal recess
 Supraoptic recess
 Infundibular recess
 Communications:
 Anterosuperiorly with lateral ventricle by interventricular foramen of Monroe.
 Posteroinferiorly with fourth ventricle by cerebral aqueduct.
 Function: Contain choroid plexus responsible for secretion of cerebrospinal fluid.
 Applied Anatomy: Blockage of cerebral aqueduct leads to dilatation of third ventricle and both
lateral ventricle. This condition is known as Hydrocephalus. It leads to mental retardation.

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Fourth Ventricle (Cavity of Hindbrain)
(*****Most Important Short Note)
 Cavity of hindbrain located between pons and medulla anteriorly and cerebellum posteriorly.
 Shape: “Tent: shape in sagittal section.
 Lateral Boundaries: Caudal part by inferior cerebellar peduncle and cranial part by superior
cerebellar peduncle.
 Posterior wall (Roof): tent shaped projects into cerebellum. Related to superior and nferior
medullary velum. Contains Median aperture (Foramen of Megendie) anf Lateral openings
(Foramen of Luschka).
 Rhomboid Fossa (Floor of fourth ventricle): Diamond shaped. Formed by posterior surface of
pons and medulla oblongata.
 Boundaries: Superolaterlly by superior cerebellar peduncle and inferolaterally by
Inferior cerebellar peduncle.
 Features seen:

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 Hypoglossal and vagal triangles
 facial colliculus
 Vestibular area
 Median sulcus
 Medial eminence
 Sulcus limitans
 Recesses:
 Dorsal median recess
 Two lateral recesses with lateral aperture.
 Communications:
 Superiorly with third ventricle by cerebral
 Inferiorly with central canal of spinal cord, and subarachnoid space by Median
aperture of Megendie.

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 Laterally with subarachnoid space by lateral aperture of Lushka.
 Function: Contain choroid plexus responsible for secretion of cerebrospinal fluid.
 Applied Anatomy: Blockage of openings leads to dilatation of all ventricles. This condition is
known as Hydrocephalus. It leads to mental retardation.
Applied Anatomy of Ventricles:
 HYDROCEPHALUS: Abnormal increase in the volume of cerebrospinal fluid within skull.
 Types:
 Non-communicating hydrocephalus: raised pressure is due to blockage between
choroid plexus and exit foramina.
 Communicating hydrocephalus: No obstruction. Causes can be excessive formation
or diminished absorption.
 INTRACRANIAL HYPERTENSION AND PAPILLEDEMA: congestion of retinal veins,
bulging forward of optic disc and edema of the disc.
Hydrocephalus
(Photo for understanding dilatation of ventricles and thinning of brain tissue)
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