Comparative anatomy on the thickness of membranous labyrinth in fish, frog and man

Histological studies were performed on the membranous labyrinths of fresh-water fish, frog and man. The thickness of membranous labyrinth was compared. The fish membranous labyrinth consisted of cartilage or cartilaginous tissue which was tough. This reason is that the fish labyrinth lacked bony labyrinth resulting in strong structure against forces from outside. This thick, cartilaginous labyrinth was also seen in frog, which has complete bony labyrinth. In man, the membranes of semicircular canal and utricle were thick, while saccular and Reissner membranes were thin.This finding may suggest a hypothesis that increase of endolymph volume takes place throughout whole labyrinth in Meniere's disease and, because of thick membranes of semicircular canal and utricle, embolymphatic hydrops is seen only in cochlea and saccule.