4th ventricle of brain

• Ventricles are the sites for CSF production.

• lateral Ventricles are the largest and most proximal. Interventricular foramen of Monro connects lateral ventricle and third ventricle

• Third ventricle connects fourth ventricle through aqueduct of sylvius.CSF flows through the entire pathway and exits fourth ventricle into surrounding CNS tissue or through spinal cord.

STRUCTURE AND FUNCTION

• As said earlier , Ventricles are the sites for CSF production. Majority of CSF is produced by choroid plexus. Although lateral Ventricles also produce most of the CSF due to their larger surface area

• CSF gets produced in all Ventricles. CSF provides support to brain, absorbs shock during trauma,keeps neurons in homeostasis, provides nutrition and contain immune cells that fight against infections of nervous system

• fourth ventricle is most inferiorly located directly draining into spinal cord.

• Superiorly it connects third ventricle through cerebral aqueduct of sylvius. Anteriorly it’s surrounding by pons and medulla . Posteriorly by cerebellum and inferiorly by spinal cord.

• lateral apertures or foramen of luschka and median aperture or foramen of magendie. These apertures help the spread of CSF around the spinal cord and surrounding neural structures. All the CSF produced does not drain out of these aperture goes into central canal of spinal cord

EMBRYOLOGY

• Neural tube forms around 4th week of gestation. Three dilation that form neural tube are procencephalon, mesencephalon and rhombencephalon.

• Procencephalon or forebrain develops into telencephalon and diencephalon . Mesencephalon becomes the midbrain while rhombencephalon grows into metencephalon ( pons and cerebellum) and melencephalon (medulla)

• Within each of these dilations that develop from neural tube are cavities that become Ventricles

• The cavity located in rhombencephalon becomes fourth ventricle

BLOOD SUPPLY

posterior inferior cerebellar artery , anterior inferior cerebellar artery and superior cerebellar artery supplies majority of blood flow to fourth ventricle

CLINICAL SIGNIFICANCE

• Ependymomas are the third most common pediatric brain tumour. They are CNS malignancies that originate from the ependymal lining of Ventricles. These tumours are often treatable or require surgery to remove these tumors

• Hydrocephalus is presence of too much of CSF, which often results problem with CSF absorption. A condition called fourth ventricle outlet obstruction is a type of non communicating Hydrocephalus where there is disconnection between subarachnoid space and ventricular system

• Dandy walker malformation (DWM)that demonstrates a cystic enlargement of fourth ventricle and agenesis or hypoplasia of cerebellar vermis . CNS disorders associated with DWM include holoprosencephaly, neural tube defects and dysgenesis of corpus callosum

Reference :- B.D chaurasia

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