The
tectorial membrane (TM) is one of two acellular gels in the
cochlea of the inner ear, the other being the
basilar membrane (BM). The TM is located above the
sulcus spiralis internus and the
spiral organ of Corti and extends along the longitudinal length of the cochlea parallel to the BM. Radially the TM is divided into three zones, the limbal, middle and marginal zones. Of these the limbal zone is the thinnest (transversally) and overlies the auditory teeth of Huschke with its inside edge attached to the spiral limbus. The marginal zone is the thickest (transversally) and is divided from the middle zone by Hensen's Stripe. It overlies the sensory
inner hair cells and electrically-motile
outer hair cells of the organ of Corti and during acoustic stimulation stimulates the inner hair cells through fluid coupling, and the outer hair cells via direct connection to their tallest stereocilia.