Mechanisms of passage and defence in the round window membrane

Abstract

The round window membrane is the only soft tissue barrier between the middle and the inner ear. Because of its location it is exposed to inflammatory processes, e.g. otitis media, within the middle ear, and to pharmacological agents instilled in the form of ear drops. These occurrences require that the membrane develops reactive and adaptive changes as defence mechanisms – including decreased permeability – in order to protect the inner ear that it bounds, and maintain its integrity and function. This article is a review of its structure and permeability characteristics, and of factors present in normal and inflamed membranes. It also describes the sequential changes that occur during inflammation, with its non‐specific and specific defence mechanisms and how these changes are related to and influence permeability.

• otic drops
• ototoxicity
• round window permeability