Vestibular lamella
Lamella vestibularis
Definition
The osseous spiral lamina (lamina spiralis ossea) is a dual bony shelf or ledge (vestibular and a tympanic lamella) which projects from the modiolus into the interior of the canal, and, like the canal, takes two-and three-quarter turns around the modiolus.
References
This definition incorporates text from a public domain edition of Gray's Anatomy (20th U.S. edition of Gray's Anatomy of the Human Body, published in 1918 – from http://www.bartleby.com/107/).