Main Model
Metencephalon : e Fourth ventricle
Fourth Ventricle
The fourth ventricle is a roughly pyramid-shaped space that
forms the cavity of the metencephalon and myelencephalon. The apex of this ventricle extends into the
base of the cerebellum, and caudally it tapers to a narrow channel
that continues into the cervical spinal cord as the central canal.
Laterally the fourth ventricle extends over the surface of the
medulla as the lateral recesses, eventually to open into the area
of the pons-medulla-cerebellum junction, the cerebellopontine
angle, through the foramina of Luschka. The irregularly shaped foramen of Magendie is located in the caudal
sloping roof of the ventricle. Although the
roof of the caudal part of the fourth ventricle and the lateral
recesses is composed of tela choroidea, the rostral boundaries of
this space are formed by brain structures. These include the cerebellum (covering about the middle third of the ventricle) and the
superior cerebellar peduncles and anterior medullary velum (covering the rostral third of the ventricle). The floor of the fourth
ventricle, the rhomboid fossa, is formed by the
pons and medulla. The only openings between the
ventricles of the brain and the subarachnoid space surrounding the brain are the foramina of Luschka and Magendie in the
fourth ventricle.