Floor Forth Ventricle

10 3 is formed by the pons and medulla fig.

Floor forth ventricle.

Specifically it spans from the obex an area in the medulla. The only naturally occurring 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. The cerebral aqueduct is a narrow canal in the midline connecting the third and fourth ventricle. Csf produced and or flowing into the fourth ventricle can exit to the subarachnoid space through lateral apertures and a single median aperture located in the inferiorportion of the roof.

It is 1 5 cm long and 1 2 mm in diameter. It is a non specific sign of a pontine mass or process with mass effect but in children is most frequently seen. The fourth ventricle has an anterior ventral floor with a characteristic diamond shape named the rhomboid fossa and a posterior dorsal tent shaped roof. The floor of the fourth ventricle the rhomboid fossa see fig.

Its floor is formed by the tegmentum of the midbrain. The flat floor of fourth ventricle sign is useful in detecting a pontine mass and is a sign of mass effect the normal floor of the fourth ventricle remember that the floor is anterior normally slopes upwards towards the midline with the facial colliculi visible on either side. The obex is also a. It has a diamond shape and is located in the upper portion of the medulla.

The fourth ventricle contains cerebrospinal fluid.