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Ventricles of brain

The brain has a series of ventricles that hold CSF (Cerebrospinal Fluid).

CSF is created by the choroid plexus and circulates through the ventricles until it is absorbed by the arachnoid layer.

CSF seems to act as a fluid cushion for the braintransports some substances into/out of the brain maintains pressure around the brain.

BRAIN VENTRICLESThe brain is bathed by the cerebrospinal fluid (CSF)Inside the brain, there are spaces (ventricles) filled with CSFThere are 4 ventricles 2 lateral ventricles are in the brain hemispheres 3rd ventricle is in the diencephalon 4th ventricle is between the pons, medulla and the cerebellum

They are connected by The foramen of monro (lateral -> third), Cerebral aqueduct ( third -> fourth), and The foramen of magendie and luschka (fourth -> subarachnoid space/cisterna magna).

Lateral Ventricle

Lateral VentricleDefinition :It is the cavity of the cerebral hemisphere.It is C-shaped.It has 3 horns & central part.Anterior Horn: in the frontal lobe.Posterior horn: in the occipital lobeInferior horn: in temporal lobe.Central part or body: in the parietal lobe.

Lateral VentricleSuperior view of the ventricular system.Lateral ventricleAnterior horn in the frontal lobe.Posterior horn in the occipital lobe.Inferior horn in the temporal lobe.Body: In the parietal lobe.The inferior and posterior horns are connected in the trigon.

Relationship of corpus callosum and third ventricle

Suprolateral surface of brain

Relationship of caudate nucleusand third ventricle

Anterior HornIn the frontal lobe.Roof: Corpus callosum (trunk)Floor: Corpus callosum (Rostrum)Caudate nucleus head

Anterior: Corpus callosum (Genu)Medially: Septum pellucidum.

Body or Central partLies in the parietal lobe.Roof: Corpus callosum (Trunk).Floor: Sloping, From lateral to medial it is formed by: Body of caudate nucleus, Upper surface of thalamusChoroid plexus, Body of fornix.Medial wall: Septum pellucidum.Lateral wall: narrow area at the meeting of roof & floor.

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Posterior HornIn the occipital lobe.

Roof, lateral wall: Are formed by the Tapetum of the corpus callosum.

Medially: There are 2 elevations: Bulb of posterior horn (formed by forceps major-2-). Calcar avis: produced by calcarine sulcus-3-.

Inferior HornIt lies in the temporal lobe.

Roof: Tapetum, Tail of caudate nucleus, Amygdaloid nucleus Stria terminalis.

Floor: Hippocampus, Fimbria of hippocampus & Collateral eminence.

Choroid Plexus of the Lateral Ventricle

is a vascular fringe of pia mater covered with the ependymal lining of the ventricular cavityThe choroid plexus projects into the ventricle on its medial aspect At the junction of the body of the lateral ventricle and the inferior horn, the choroid plexus is continued into the inferior horn.

Fourth ventricle

Fourth Ventricle

A tent-shaped cavity filled with cerebrospinal fluid. lined with ependyma continuous above with the cerebral aqueduct of the midbrain and below with the central canal of the medulla oblongata and the spinal cord

Situated anterior to the cerebellum and posterior to the pons and the superior half of the medulla oblongata

The fourth ventricle possesses Lateral boundaries Roof, and Rhomboid-shaped floor.

Lateral Boundaries

The caudal part .... the inferior cerebellar peduncle The cranial part ..... the superior cerebellar peduncle.

Roof or Posterior WallThe tent-shaped roof projects into the cerebellum The superior part....medial borders of the two superior cerebellar peduncles and a connecting sheet of white matter called the superior medullary velum The inferior part ..... the inferior medullary velum, which consists of a thin sheet devoid of nervous tissue and formed by the ventricular ependyma and its posterior covering of pia mater

Fourth ventricle communicates with the subarachnoid space through a single median and two lateral apertures.

In the midline ,the roof is pierced by a large aperture, the median aperture or foramen of Magendie .Lateral recesses extend laterally around the sides of the medulla and open anteriorly as the lateral openings of the fourth ventricle, or the foramina of Luschka .

Floor or Rhomboid Fossa

The diamond-shaped floorformed by the posterior surface of the pons and the cranial half of the medulla oblongata is divided into symmetrical halves by the median sulcus.the medial eminence, ... the sulcus limitans. vestibular area ..vestibular nuclei

Nerve nuclei in floor of fourth ventricle

The facial colliculus the inferior end of the medial eminence produced by the fibers from the motor nucleus of the facial nerve looping over the abducens nucleusSubstantia ferrugineaLies at the superior end of the sulcus limitans, there is a bluish-gray area, nerve cells contain melanin pigment. Stria medullarisStrands of nerve fibers derived from the arcuate nuclei, emerge from the median sulcus and pass laterally over the medial eminence and the vestibular area and enter the inferior cerebellar peduncle to reach the cerebellum

Facial colliculus

Choroid Plexus of the Fourth Ventricle is formed the posterior inferior cerebellar arteries.

The choroid plexus has a T shape The vertical part of the T is double .Is formed from the highly vascular tela choroidea. The tela choroidea is a two-layered fold of pia mater that projects through the roof of the ventricle and is covered by ependyma.