Anatomy
Stanley A. Gelfand in Hearing, 2017
The inner ear, beyond the oval window, is composed of the vestibule, the cochlea, and the vestibular apparatus. A membranous duct is continuous throughout these. In the cochlea, it separates the perilymph-filled scala vestibuli and scala tympani above and below from the endolymph-filled scala media between them. The scala media contains the organ of Corti, whose hair cells are the sensory receptors for hearing. When stimulated, the hair cells initiate activity in the auditory nerve fibers with which they are in contact. The auditory nerve leaves the inner ear through the internal auditory canal (internal auditory meatus), enters the brain at the angle of the pons and cerebellum, and terminates in the brainstem at the cochlear nuclei. We are now in the central auditory system.
Restoration: Nanotechnology in Tissue Replacement and Prosthetics
Harry F. Tibbals in Medical Nanotechnology and Nanomedicine, 2017
The cochlea is a hollow tapering helix supported by a bony spiral shelf, the osseous spiral lamina, which winds around a central core, the modiolus. The cochlea’s spiral cone geometry, like a French horn or conch shell, acts as a mechanical acoustical transform to select for different vibration frequencies along its interior. The interior of the cochlea is separated into two fluid-filled chambers (the scala vestibuli and scala tympani or upper and lower ducts) by a thin sac, called the cochlear duct, filled with gelatinous material. The large end of the spiral is sealed from the outer ear by two membranes, the oval and round windows, on either side of the cochlear duct. The duct separates the two chambers all the way up the spiral to its apex, where there is a small opening between them. The sensory hair cells are inside the cochlear duct adjacent to a thin layer of tissue (the tectorial membrane). Each hair cell has a group of stereo-cilia projecting into the viscous gelatin, which resonate with sound [286,287].
Noise, hearing and vibration
Nicholas Green, Steven Gaydos, Hutchison Ewan, Edward Nicol in Handbook of Aviation and Space Medicine, 2019
Inner ear: Cochlea Fluid-filled tube divided into three cavities (scala media, scala tympani and scala vestibuli).Basilar membrane forms a partition between the scala media and scala tympani, contains the Organ of Corti.Organ of Corti contains approximately 20,000 hair cells; hair-like projections (stereocilia) attached.Hair cells respond based on sound frequency; create signals that become nerve impulses.Vestibular system: Utricle, saccule, three semicircular canals.Semicircular canals respond to angular acceleration; utricle and saccule respond to linear acceleration (control posture and balance).
The applications of targeted delivery for gene therapies in hearing loss
Published in Journal of Drug Targeting, 2023
Melissa Jones, Bozica Kovacevic, Corina Mihaela Ionescu, Susbin Raj Wagle, Christina Quintas, Elaine Y. M. Wong, Momir Mikov, Armin Mooranian, Hani Al-Salami
The complex structure of the mammalian ear is divided into three primary sections, classified as the outer, middle, and inner ear, with all parts required to work in an organised, controlled synergistic nature for hearing to occur. Focus here will be on the inner ear, which has roles in both hearing and balance [38]. The inner ear contains the cochlea where auditory signals are transduced. Located within the cochlea are three ducts, termed the scala vestibule, scala media, and scala tympani. Within the scala media of the cochlea, the organ of Corti is positioned, with the primary function of transducing auditory signals. The organ of Corti contains both inner and outer hair cells, being mechanosensory hair cells arranged in rows, with three rows of outer hair cells and one row of inner hair cells in the luminal half of the organ. Also located within are supporting cells of a non-sensory nature, positioned throughout the basement membrane to the luminal surface in a highly organised pattern [23,39,40].
Human inner ear blood supply revisited: the Uppsala collection of temporal bone—an international resource of education and collaboration
Published in Upsala Journal of Medical Sciences, 2018
Xueshuang Mei, Francesca Atturo, Karin Wadin, Sune Larsson, Sumit Agrawal, Hanif M. Ladak, Hao Li, Helge Rask-Andersen
The draining veins of the vestibular organ and cochlea were identified (Figure 1, Figure 3(B), Figure 5(A) upper inset, Figure 5(B), Figures 8, 9, and 11). The inferior cochlear vein exits at the floor of the scala tympani (ST) near the opening of the cochlear aqueduct and the round window (RW). Several draining veins merge here, with two major kind of variations, depending on how the anterior and posterior spiral modiolar veins develop and on the posterior and anterior vestibular veins (Figure 11). Occasionally, veins of the RW could be detected. The posterior spiral veins received several tributaries from the lateral scala tympani wall. A draining vein in the IAC could not be evaluated with the current techniques. Cochlear veins converged and concerted in an area vasculosum (our term) near the entering arteries at the basal turn of the cochlea.
Cochlear volume as a predictive factor for residual-hearing preservation after conventional cochlear implantation
Published in Acta Oto-Laryngologica, 2018
Masahiro Takahashi, Yasuhiro Arai, Naoko Sakuma, Kenichiro Yabuki, Daisuke Sano, Goshi Nishimura, Nobuhiko Oridate, Shin-ichi Usami
The concept of CI with hearing preservation by atraumatic soft surgery is well established. Holden et al. reported that full electrode insertion in the scala tympani is important for residual hearing preservation [12]. Lateral wall implants were associated with greater rates of full scala tympani insertion as compared with perimodiolar implants [13]. On the other hand, trans-scalar electrode excursion during implantation is a strong predictor of loss of residual hearing [14]. Therefore, techniques to decrease the risk of electrode excursion from the scala tympani are expected to improve residual hearing and CI performance [14]. According to our hypothesis that residual hearing preservation after CI is associated with cochlear volume and CDL, the electrode array can remain fully in the scala tympani in patients with large cochlear volume and longer CDL, with the risk of electrode excursion from the scala tympani though to be reduced in such patients.
Related Knowledge Centers
- Basilar Membrane
- Cochlear Duct
- Helicotrema
- Inner Ear
- Ossicles
- Perilymph
- Signal Transduction
- Eardrum
- Round Window
- Vestibular Duct