The bony labyrinth refers to the outer bony covering of the labyrinth or the inner ear. It lies within the petrous part of the temporal bone and is lined by periosteum on the inside. The bony labyrinth hosts inside it, the membranous labyrinth. The latter is filled with endolymph. The space between the membranous and the bony labyrinth is filled up by a fluid called the perilymph.The bony ...