Otosclerosis: Formation of spongy bone in the labyrinth capsule which can progress toward the STAPES (stapedial fixation) or anteriorly toward the COCHLEA leading to conductive, sensorineural, or mixed HEARING LOSS. Several genes are associated with familial otosclerosis with varied clinical signs.Stapes: One of the three ossicles of the middle ear. It transmits sound vibrations from the INCUS to the internal ear (Ear, Internal see LABYRINTH).Stapes Surgery: Surgery performed in which part of the STAPES, a bone in the middle ear, is removed and a prosthesis is placed to help transmit sound between the middle ear and inner ear.Oval Window, Ear: Fenestra or oval opening on the lateral wall of the vestibular labyrinth adjacent to the MIDDLE EAR. It is located above the cochlear round window and normally covered by the base of the STAPES.Hearing Loss, Conductive: Hearing loss due to interference with the mechanical reception or amplification of sound to the COCHLEA. The interference is in the outer or middle ear involving the EAR CANAL; TYMPANIC MEMBRANE; or EAR OSSICLES.Stapes Mobilization: An operation to remobilize the footplate of the stapes to relieve conductive hearing impairment caused by its immobilization through otosclerosis or middle ear disease. (Stedman, 26th ed)Ear Ossicles: A mobile chain of three small bones (INCUS; MALLEUS; STAPES) in the TYMPANIC CAVITY between the TYMPANIC MEMBRANE and the oval window on the wall of INNER EAR. Sound waves are converted to vibration by the tympanic membrane then transmitted via these ear ossicles to the inner ear.Ossicular Prosthesis: An implant used to replace one or more of the ear ossicles. They are usually made of plastic, Gelfoam, ceramic, or stainless steel.Temporal Bone: Either of a pair of compound bones forming the lateral (left and right) surfaces and base of the skull which contains the organs of hearing. It is a large bone formed by the fusion of parts: the squamous (the flattened anterior-superior part), the tympanic (the curved anterior-inferior part), the mastoid (the irregular posterior portion), and the petrous (the part at the base of the skull).Ear, Middle: The space and structures directly internal to the TYMPANIC MEMBRANE and external to the inner ear (LABYRINTH). Its major components include the AUDITORY OSSICLES and the EUSTACHIAN TUBE that connects the cavity of middle ear (tympanic cavity) to the upper part of the throat.Tympanic Membrane: An oval semitransparent membrane separating the external EAR CANAL from the tympanic cavity (EAR, MIDDLE). It contains three layers: the skin of the external ear canal; the core of radially and circularly arranged collagen fibers; and the MUCOSA of the middle ear.Malleus: The largest of the auditory ossicles, and the one attached to the membrana tympani (TYMPANIC MEMBRANE). Its club-shaped head articulates with the INCUS.Tympanoplasty: Surgical reconstruction of the hearing mechanism of the middle ear, with restoration of the drum membrane to protect the round window from sound pressure, and establishment of ossicular continuity between the tympanic membrane and the oval window. (Dorland, 28th ed.)Incus: One of three ossicles of the middle ear. It conducts sound vibrations from the MALLEUS to the STAPES.Ear Canal: The narrow passage way that conducts the sound collected by the EAR AURICLE to the TYMPANIC MEMBRANE.Round Window, Ear: Fenestra of the cochlea, an opening in the basal wall between the MIDDLE EAR and the INNER EAR, leading to the cochlea. It is closed by a secondary tympanic membrane.Perilymph: The fluid separating the membranous labyrinth from the osseous labyrinth of the ear. It is entirely separate from the ENDOLYMPH which is contained in the membranous labyrinth. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed, p1396, 642)Ossicular Replacement: Surgical insertion of an implant to replace one or more of the ear ossicles.Fenestration, Labyrinth: The surgical creation of a new opening in the labyrinth of the ear for the restoration of hearing in cases of OTOSCLEROSIS. (Dorland, 27th ed)Basilar Membrane: A basement membrane in the cochlea that supports the hair cells of the ORGAN OF CORTI, consisting keratin-like fibrils. It stretches from the SPIRAL LAMINA to the basilar crest. The movement of fluid in the cochlea, induced by sound, causes displacement of the basilar membrane and subsequent stimulation of the attached hair cells which transform the mechanical signal into neural activity.