3-DIMENSIONAL RECONSTRUCTION OF THE MEMBRANOUS VESTIBULAR LABYRINTH IN THE TOADFISH, OPSANUS-TAU

Membranous vestibular labyrinths from the oyster toadfish, Opsanus tau , were fixed, dissected from the animal, stained, and embedded in rect angular blocks of clear histological resin. Photomicrographs of comple te embedded labyrinths were taken from six orthogonal directions and u sed to construct three-dimensional (3D) geometrical models of the semi circular canals, ampullae, utricular vestibule and common crus. Membra nous ducts and ampullae were modeled using a set of cross-sectional el liptical curves laced together to generate curved tubular models of ea ch structure. The ensemble of these curved tubes was used to generate a complete 3D reconstruction of the outside surface of the membranous labyrinth. When viewed from six orthogonal directions, reconstructions closely matched the embedded tissue. Dimensions of the reconstruction and histological sections were compared to measurements of fresh tiss ue taken from the same animals prior to fixation and used to correct t he reconstructions for tissue shrinkage. Results provide estimates of the endolymphatic volumes, local cross-sectional areas and elliptical eccentricities as well as 3D orientations of the geometric canal plane s relative to the skull. Ten micrometer histological sections of the m aterial were also prepared to measure wall thickness in various region s of the labyrinth. (C) 1998 Elsevier Science B.V. All rights reserved .