The Utriculo-Endolymphatic Valve

In 1928 Bast¹described a fold in the posterior wall of the utricle at the site of the utricular duct which he named the utriculoendolymphatic valve. This name was suggested by its anatomic structure and position. It appeared to guard the opening of the utricular duct into the utricle. This structure was seen first in sections from the ear of a human fetus. In 1929 Wilson and Anson²described the structure in a child, and later that year they also described it in the adult human ear,³having observed it in eleven different specimens. A thorough study with reconstructed models of the utriculo-endolymphatic valve as it occurs in different animals was made in 1931 by Hoffman and Bast,⁴who concluded that this structure "is a definite and constant feature of the membranous labyrinth of the mammalian ear." Roberts⁵studied the utriculo-endolymphatic valve in the