abnormal membranous labyrinth morphology abnormal cochlear labyrinth morphology any structural anomaly in the portion of the membranous labyrinth concerned with the sense of hearing (vs. the vestibular labyrinth, which is concerned with the sense of equilibration) and innervated by the cochlear nerve; it is located within the cochlea of the bony labyrinth, and consists of the cochlear duct, which contains the spiral organ abnormal labyrinthus cochlearis abnormal organ of hearing MP:0004426 MPheno.ontology