part of part of cochlear labyrinth basement membrane of epithelium cochlear basement membrane cochlea basement membrane basement membrane of cochlear labyrinth The the continuous basement membrane found within the membranous labyrinth of the cochlea, known to extend from the limbus, down to the inner sulcus, across the basilar membrane, up to the external sulcus to the spiral prominence and radiating into the spiral ligament ensheathing the root cell processes. UBERON:0011922