Skeletal System
David Sturgeon in Introduction to Anatomy and Physiology for Healthcare Students, 2018
The remaining bones of the axial skeleton are the tiny ossicles of the ears and the singular hyoid bone of the neck. There are three ossicles in each ear: the malleus, the incus and the stapes (better known as the hammer, anvil and stirrup). They are situated in the middle ear and collectively transmit sound from the ear drum (tympanic membrane) to the fluid-filled inner ear and auditory nerve (see Chapter 12). The final bone of the axial skeleton is the hyoid bone and is the only bone in the body that is not directly attached to another. Instead, it is anchored in place at the base of the tongue by a series of muscles and ligaments. The hyoid bone is U or horseshoe-shaped and is also known as the lingual (tongue) bone since it supports the weight of the tongue and allows us to articulate words during speech. Fractures of the hyoid bone are rare and are usually caused by strangulation or traumatic injury to the neck.
Growth of the Ear Capsule
D. Dixon Andrew, A.N. Hoyte David, Ronning Olli in Fundamentals of Craniofacial Growth, 2017
This is sometimes called Treacher-Collins-Franceschetti syndrome, or mandibulofacial dysostosis, a symmetric dysplasia (as compared with hemifacial microsomia) (Bergsma, 1969, 1971b; Poswillo, 1975a,b, 1988; Kolar et al., 1987; Pron et al., 1993). There is an antimongoloid slant of the eyes, coloboma of the lower eyelid, microtia, and other ear deformities (external ear deformities as listed before), hypoplastic zygomatic arches, large mouth, and in some, cleft palate (Bergsma, 1969). (See Figure 10.24 in Chapter 10: Growth of the Orbit). The middle ear is involved also (Pron et al, 1993: CT assessments in a large series of pediatric patients), the ossicles dysmorphic or missing, adherent or assimilated to the cavity walls. There is a conductive hearing loss due to malformed or missing ossicles. The inner ear is normal in all. (Note, however, that Suehiro and Sando, 1979, listed cochlear, vestibular and semicircular canal abnormalities in mandibulofacial dysostosis).
Special Senses
Pritam S. Sahota, James A. Popp, Jerry F. Hardisty, Chirukandath Gopinath, Page R. Bouchard in Toxicologic Pathology, 2018
The middle ear contains a chain of three small bones called the ossicles. These are most often termed the malleus, incus, and stapes but also termed the hammer, anvil, and stirrup respectively. The malleus (hammer) is attached to the tympanic membrane and articulates with the incus (anvil) (Figure 23.5a). The incus articulates with the stapes (stirrup) and the footplate of the stapes is attached to the membranous oval window of the cochlea. There are two muscles associated with ossicles; the tensor tympani muscle (innervated by the trigeminal nerve) is attached to the malleus and the stapedius muscle (innervated by the facial nerve) is attached to the stapes. Contraction of these muscles is associated with a reflex induced by loud sounds and contraction of the muscles restricts movement of the ossicles and reduces transmission of sound.
Outcomes of ossicular disruption in traumatic facial paralysis: a case series
Published in Acta Oto-Laryngologica, 2021
Xudong Yan, Pei Liu, Caili Ji, Min Zhang, Xiaoheng Zhang, Fugao Zhu, Tao Fu
Temporal bone trauma can damage important internal structures, leading to severe functional impairment, such as peripheral facial paralysis and conductive hearing loss. Injury to the facial nerve causes peripheral facial paralysis, and peripheral regions (from the geniculate ganglion to the mastoid segment) account for more than 70% of all cases [1,2]. Ossicular disruption is one of the main causes of conductive hearing loss, which includes several types such as incudostapedial or incudomalleolar joint separation, dislocation of the incus, dislocation of the malleoincudal complex, stapediovestibular dislocation, fractures of the ossicles, and so forth [3]. Patients with traumatic hemotympanum and tympanic membrane perforation usually recover within weeks to several months without any intervention [4]. However, disruption of the ossicular chain can cause hearing loss with 30 dB or more and sometimes needs a surgical intervention for maximum recovery. Facial nerve decompression and ossiculoplasty are usually performed simultaneously using the posterior tympanum approach for patients diagnosed with both traumatic facial nerve paralysis and ossicular disruption. However, tympanotomy using the transcanal approach was a primary surgical technique most widely used for traumatic ossicular disruption [3–9]. This study aimed to investigate hearing outcomes of simultaneous ossiculoplasty and facial nerve decompression and the improvement in postoperative hearing outcomes using the posterior tympanum approach compared with the transcanal approach.
Emerging therapies for human hearing loss
Published in Expert Opinion on Biological Therapy, 2022
Elise Ajay, Niliksha Gunewardene, Rachael Richardson
The peripheral hearing pathway begins at the outer ear where the pinna picks up sound waves and funnels them through the ear canal to vibrate the eardrum. The motion of the eardrum is mechanically transmitted through the middle ear via the ossicles, with the smallest of these bones, the stapes, connected to the cochlea of the inner ear via the oval window membrane. The movement of the oval window translates to vibration of the basilar membrane. This motion stimulates the cochlear hair cells, generating nerve impulses in spiral ganglion neurons which transmit to the auditory cortex via the brainstem. The sensorineural and structural elements of the cochlea and the ascending auditory pathway are shown in Figure 1.
Design of a resilient ring for middle ear’s chamber stapes prosthesis
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2018
Emilia Anna Kiryk, Konrad Kamieniecki, Monika Kwacz
Stapes prostheses are used for surgical treatment of otosclerosis, which is an illness affecting auditory ossicles located in the middle ear. The ossicles (malleus, incus and stapes) link the outer and inner ear and transmit sound vibrations from the tympanic membrane to the oval window (OW). The stapes footplate (SF) is suspended on a highly elastic annular ligament (AL) in the OW niche. The AL enables the stapes to vibrate and to generate a pressure wave in the perilymph fluid. Otosclerosis immobilizes the stapes due to stiffening of the AL. This leads to a decrease in stimulation of the perilymph and manifests by conductive hearing loss (CHL). Otosclerosis is the cause of almost 22% of all CHL (Potocka et al. 2010).