Attachment of the inner sensory cell hairs to the tectorial membrane. A scanning electron microscopic study.

The residue of tectorial membrane insertion of cochlear inner sensory cell hairs was studied under a scanning electron microscope. In addition to the clear imprints resulting from outer sensory cell hair insertions, an adjacent medial row of bow-shaped imprints was noted on the base of the tectorial membrane. The relative position of these imprints corresponded to the location and the size of the inner cell hairs. These imprints were thus thought to arise from the insertion of the inner sensory hair cells. Such imprints were found only in the lower turns of the cat's cochlea, but not on the guinea pig tectorial membrane. Thus an actual physical contact between the tectorial membrane and the inner sensory cell hiars may exist in some species but not in others, and when there is physical contact, it is thought to be less firm than that of the outer sensory hair cells.