Studies on the patency of the cochlear aqueduct were made on 330 temporal bones histopathologically, and clinical significances of cochlear aqueduct patency were discussed. Large patent cochlear aqueduct of 0.2mm and over in diameter at its narrowest point in the otic capsule was found in 25 out of 330 temporal bones, i. e., 7.6% of bones. Patency of cochlear aqueduct renders possible round window membrane rupture through rises in cerebrospinal fluid pressure, perilymph oozer, and a two-way spread of infection between the perilymph and cerebrospinal fluid.
