part of part of middle ear zone of bone organ promontory of tympanic cavity promontorium tympani The promontory of the tympanic cavity, better known as the cochlear promontory is a rounded hollow prominence, formed by the projection outward of the first turn of the cochlea. It is placed between the fenestrae, and is furrowed on its surface by small grooves, for the lodgement of branches of the tympanic plexus. A minute spicule of bone frequently connects the promontory to the pyramidal eminence. BTO:0003089 promontorium Wikipedia:Promontory_of_tympanic_cavity FMA:77694 UBERON:0035964 promontory of the tympanic cavity tympanic cavity promontory