The promontory of the

tympanic cavity The tympanic cavity is a small cavity surrounding the bones of the middle ear. Within it sit the ossicles, three small bones that transmit vibrations used in the detection of sound. Structure On its lateral surface, it abuts the external auditory ...

, also known as the cochlear promontory is a rounded hollow prominence, formed by the projection outward of the first turn of the

cochlea The cochlea is the part of the inner ear involved in hearing. It is a spiral-shaped cavity in the bony labyrinth, in humans making 2.75 turns around its axis, the modiolus. A core component of the cochlea is the Organ of Corti, the sensory or ...

. It is placed between the

oval window The oval window (or ''fenestra vestibuli'' or ''fenestra ovalis'') is a membrane-covered opening from the middle ear to the cochlea of the inner ear. Vibrations that contact the tympanic membrane travel through the three ossicles and into the in ...

and the

round window The round window is one of the two openings from the middle ear into the inner ear. It is sealed by the secondary tympanic membrane (round window membrane), which vibrates with opposite phase to vibrations entering the inner ear through the oval ...

, and is furrowed on its surface by small grooves, for the lodgement of branches of the

tympanic plexus In the tympanic cavity, the tympanic nerve (a branch of CN IX) divides into branches which, along with sympathetic fibres from the carotid plexus, form the tympanic plexus. This plexus is located on the surface of the promontory. This tympanic pl ...

. A minute spicule of bone frequently connects the promontory to the

pyramidal eminence The pyramidal eminence (pyramid) is a conical projection in the middle ear. It is situated immediately behind the fenestra vestibuli (oval window), and in front of the vertical portion of the facial canal; it is hollow, and contains the stapedi ...

Additional images

File:Gray913.png, Coronal section of right temporal bone. File:Gray914.png, The medial wall and part of the posterior and anterior walls of the right tympanic cavity, lateral view.

References

External links

* Ear {{Musculoskeletal-stub