Surgical anatomy of the epitympanic space.

A clear understanding of the surgical anatomy of the epitympanic space is crucial in modern otologic surgery. The tortuous facial nerve within the tight confines of this region presents important surgical challenges, especially when normal anatomy is obscured by disease. Microdissections of 20 human temporal bones were carried out with particular emphasis on the spatial relations of the facial nerve with various temporal bone landmarks. Measurements were made through a standard transmastoid approach to ensure clinical relevance. A high margin of safety can be achieved by observing consistent landmarks and relations in dealing with the facial nerve. We demonstrated the limitations of the transmastoid approach, particularly in accessing the labyrinthine segment of the facial nerve.