VELA MEDULLARIA

VELA MEDULLARIA (brain sails), thin plates forming part of the roof of the fourth ventricle. Velum medullare anticum s. superius, a plate of white matter, is located between the cerebellar pedunculi and the corpora quadrigemina, forming the anterior superior part of the roof of the fourth ventricle; it is covered from above by the fused lingula cerebelli; in it cross the following fibers: in the lower parts - fibers of Gowers' bundle (see Gowers' bundle), in the upper parts - the trochlear nerve (see trochlearis nerve). From the anterior, narrower end, the frenuli veli medullaris anterioris extend, which are directed to the corpora quadrigemina posterioris. Velum medullare posticum s. inferius (s. valvula Tarini), a very thin plate forming the lower part of the roof of the fourth ventricle; with its upper edge it is attached to the cerebellum, below it passes into an epithelial plate (membrana obturatoria), which is attached to the edges of the lower parts of the rhomboid fossa.