4th Ventricle of Brain
and Cerebral Aqueduct
Learning Objectives
 At the end of lecture student should able to:
 Describe the location of different ventricles.
 Discuss the boundaries of 4th ventricle.
 Describe the structure present in the floor of 4th ventricle.
 Explain the location of cerebral aqueduct.
 Explain the formation and circulation of CSF.
 Define the blood brain barrier.
 Discuss the appllied anatomy of CSF circulation.
The Ventricular System.
The Ventricular System.
Ventricles are fluid filled cavities located within the brain; 2 lateral ventricles, 3rd ventricle and 4th
ventricle.
2 lateral ventricles communicate through interventricular foramina 3rd ventricle4th ventricle by the
cerebral aqueduct.
The 4th ventricle  central canal of spinal cord and subarachnoid space through 3foraminea.
Forth Ventricle
Diamond shape when viewed superiorly and tent-
Last and lowest ventricle .
Cavity of hindbrain.
Situated b/w pons ad medulla infront and
cerebellum behind.
Communication
With 3rd ventricle cerebral aqueduct.
shaped when viewed laterally.
Inferiorly communicate with central canal of
medulla and spinal cord.
Dorsally---median aperture(FORAMEN OF
MAGENDI) ad lateral aperture(FORAMEN
OF LUSCHKA) communicate with
subarachnoid space.
Fourth Ventricle
 ROOF----tent shaped, projects into
cerebellum.
 Superior –lateral: formed by supr.cerebellar
 Peduncle
 Connecting sheet of white matter—superior medullary vellum.
 Inferior part– inferior medullary vellum
 Tela choroidea of 4th v.
 Median aperture—foramen of Magendie.
 Lateral aperture—foramina of Luschka.
FLOOR --RHOMBOIDAL FOSS
 Median sulcus.
 Median eminence—elevation on either side of Median sulcus.
 Lateral sulcus/sulcus limitansVESTIBULAR AREA– vestibular nuclei.
 Superior end of sulcus limit Substantia ferruginea
 Facial colliculusinferior end of medial eminence--produced by fibres of facial nerve loop
around the abducent nuclues.
 VAGAL TRIANGLE---dorsal nucleus of vagus.
 HYPOGLOSSAL TRIANGLE-----hypoglossal nucleus.
Choroid Plexus of 4th ventricle
Cerebral Aqueduct
The cerebral aqueduct is about—1.8 cm long.
Connects 3rd to 4th ventricle.
It lined with ependyma cells with central gray area.
The direction of flow is from 3rd4th ventricle.
There is no choroid plexus in the cerebral aqueduct.
Tela Choroidea
CSF Circuration
CSF produced by choroid plexus of ventricles and
circulates thru subarachnoid space ad
ventricles, before being absorbed into Dural
venous sinuses.
Choroid plexus is located in roof of 3rd &4th
ventricles &floor and body of inferior horn of lateral ventricle.
Choroid plexus is composed of highly vascular
tissue called TELA CHOROIDEA
Total volume of CSF—130ml .
Normal pressure is 60—150 mm of water.
Colorless contain:
Glucose ½ of blood.
Traces of protein.
Few lymphocytes (0—3 cells/cmm)
Functions:
Nourishes the brain tissue.
Protection.
Cushion and mechanical buoyancy—brain.
Removal of products—neuronal metabolism.
Pathway for the pineal gland secretion –pituitary gland.
Circulation
Blood Brain Barrier
 The isolation of nervous tissue of brain and spinal cord from blood is called –blood brain barrier.
 Permeability of BBB is inversely related to the size of molecule and directly to the lipid solubility
of molecule.
 Structure:
 Endothelial cells of capillary.
 Continuous basement membrane.
 Foot process of astrocytes.
Hydrocephalus
Types of Hydrocephalus
Pathophysiology and Etiology
Treatment