Ultrastructure of the normal human organ of Corti. New anatomical findings in surgical specimens

Abstract

Conclusion A thorough scanning electron microscopy (SEM) investigation of immediately fixed human adult cochleae obtained during surgery for petro-clival meningiomas conveyed new information about morphology.

Objective To investigate the ultrastructure of human adult cochleae using SEM.

Material and methods Two human cochleae were decalcified, fixed with glutaraldehyde and osmium and prepared for SEM.

Results The excellently preserved morphology showed the pathways of nerve fibres through the organ of Corti. Undulating lateral cell membranes of Hensen and Claudius cells created an enlarged surface that may be important for homoeostasis. The distal attachment of the tectorial membrane to the reticular lamina was present in the shape of a marginal net, which was extended through marginal pillars. Stereocilia imprints extended as far as the distal end of the marginal pillars. The presence of an irregularly distributed fourth row of outer hair cells attached to the marginal pillars raises questions about differences in the excitation of the last row of outer hair cells as a result of differences in the composition of the tectorial membrane.

• Glycocalyx
• imprints
• innervation
• tectorial membrane attachment
• nerve fibres
• outer spiral bundle
• scanning electron microscopy
• stereocilia
• supporting cells
• marginal net