Dimensiomnal anatomy of the vestibular aqueduct and the endolymphatic sac in human temporal bones.

Abstract

The anatomy of the vestibular aqueduct (VA) and rugose potion (RP) of the endolymphatic sac (ES) was examined. Serial horizontal sections of 79 normal temporal bones of individuals aged 20 to 102 yeras were used. Medial view graphic reconstruction of the VA was performed for each specimen in order to determine the area, length, and location of the VA. The relationship between the width of the VA and the area of the VA, and the relationship between the degree of development of the VA and the degree of development of the temporal bone (periaqueductal pneumatization and the otic capsule in the periaqueductal region) were also investigated. In addition, measurements of the RP were made, further histo-logical study of the RP was performed in 30 selected specimens.
We found that 1) the VA in adult temporal bones varies in size and can be classified as hypoplastic, normoplastic, or hyperplastic; 2) many of the VAs in each group mentioned above have similar sizes, although they vary in length, angle, or location; 3) all or most of the RP was located within the VA in all but one specimen, which had a hypoplastic VA; 4) the histology of the RP was characteristic in each type of VA; 5) the degree of development of the VA seems to correlate with the degree of development of the otic capsule in the periaqueductal region.