Development of the cochlea and its coiling mechanism.

The growth and shape of the membraneous labyrinth appears to be organized and restricted by the formation of the cartilaginous capsule. Coiling of the cochlear duct appears to be the result of the physical barrier and support provided by the cartilage cells differentiating from mesenchyme surrounding the otocyst. In addition, tissue interactions between this mesenchyme and the developing cochlear duct may be the source of a genetic message for the coiling mechanism.