4th Ventricle

Site : between = Ant : pons & upper part of medulla

Post : cerebellum

Shape : tent-shaped (side), diamond-shaped (behind)

Boundaries : Above & Lat = Sup cerebellar peduncle

                    Below & Lat = Inf cerebellar peduncle, Cuneate and Gracile tubercles

Angles : 

• upper angle
• lower angle 
• Rt & Lt lateral angles

Floor : diamond-shaped

• Upper pontine part : Facial colliculus, Median eminence, Pontine vestibular area, Sup fovea

• Lower medullary part : Vagal trigone, Hypoglossal trigone, Vestibular area, Inf fovea  

Roof :

 a) Upper part => med border 2 sup cerebellar peduncles & sup medullary velum

 b) Lower part => 

         1) upper area : nodule of cerebellum & inf medullary velum on each side

    

        2) lower area : ependyma & pia mater, invaginated by choroid plexus

                                       

 *lowest part : F. of Magendi which open to subarachnoid space* 

 c) Recesses => Median recess, 2 Lat recesses ( open to subarachnoid space by F. of Luschka ) 

Connections : 

• Upper angle : aqueduct of sylvius => connect 4th ventricle to 3rd ventricle

• Lower angle : central canal of closed medulla => connect 4th ventricle to central canal of spinal cord

• Roof : F. of Magendi & F. of Luschka => connect 4th ventricle to subarachnoid space