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At least 127 records · Page 7Linked to original sources
PubMed1987

The mineral content of the middle ear ossicles. A radiologic and chemical study on normal and diseased ossicles.

The underlying mechanism responsible for bone resorption in chronic otitis media with or without cholesteatoma is not sufficiently well documented. Certain areas in the middle ear are affected more often than others. The most frequent site of bony erosion in the ossicular chain is the long process of the incus. The mineral content of the ossicular chain was investigated with a clinical radiologic technique (polytomography). The findings were correlated with chemical measurements of the mineral content in normal and diseased ossicles. A poor correlation between the radiologic findings and the chemical assessment was found. The mineral content of ossicles obtained from ears with chronic otitis was similar to that of specimens obtained from healthy middle ears. The findings indicate that the demineralization process seems to be localized to a narrow zone of the ossicle and that this zone cannot be adequately visualized by standard radiologic techniques.

Absorptiometry, Photon↗
PubMed1989

[The functional significance of the suspending ligaments of the ear ossicle chain].

The contraction of the tensor tympani muscle has not enough force to stabilise the drum membrane-malleus complex against a negative pressure in the external ear nor against a hyperpressure in the middle-ear, as in sneezing, Valsalva's manoeuvre, etc. The ossicular ligaments must therefore perform this task. It was shown in experiments with fresh temporal bone preparations that the superior malleolar ligament diminishes the pressure-induced displacements of the malleus. This proves that this often neglected ligament has true functional significance. The most important ligament, which retains the malleus against an outward displacement, however, is the sturdy connective tissue between the cochleariform process and the malleus' handle, enveloping the tendon of the tensor tympani muscle and crossing the middle-ear cleft together with the tendon. These connective tissue strands are much too strong for a simple sheath of tendon, as can be seen histologically. In consideration of the fact that the functional significance surpasses the function of a pure tendon sheath, this ligamentous structure can be called the malleo-cochleariform ligament.

Ear Ossicles↗
PubMed1994

[Is reuse of autologous ear ossicles in cholesteatoma or chronic suppurative otitis media justified?].

From the 1950s onwards ossicular bone autografts have been used to restore the middle ear sound conduction mechanism. Controversy still exists regarding the appropriateness of autologous ossicular bone grafts in chronic middle ear diseases. This communication is based on a study of 149 ossicles surgically removed from 120 patients with different ear diseases, at the Department of Otolaryngology, Head and Neck Surgery of the University of Wuerzburg. It is the object of this study to systematically investigate the histological findings in the ossicles in cholesteatoma and chronic suppurative otitis media, and also to try to assess their significance. For comparison the ossicles of traumatic subluxation and otosclerosis are also included in our material. In about one-fourth of the incidences of cholesteatoma, squamous epithelium is found adherent to the ossicles with subepithelial connective tissue of varying thickness separating the matrix from the involved ossicle so that the matrix is never in direct contact with the underlying bone. Osteomyelitis is shown in both groups. Bone resorption predominates in the complicated metaplastic process due to the action of osteoclasts irrespective of the cholesteatoma group or the chronic otitis media group. Bone erosion is evident not only on the surface of the ossicles but also in the bone. On the other hand, ossicles in the groups of traumatic subluxation and otosclerosis remain histologically normal without evidence of pathologic changes. On the basis of these histological observations and on account of the high probability of adherent squamous epithelium in our opinion autologous ossicles from cholesteatoma and chronic suppurative otitis media should not be used in reconstructive middle ear surgery.

Adolescent↗
PubMed1990

[The morphometry of the ear ossicles in humans during development].

The dimensions and the mass of the auditive ossicles was determined bilaterally in 100 human fetuses, of each sex aged from 21 to 40 weeks and 20 individual adults aged 18 to 40 years. It was found that the development of auditive ossicles in human is not completed during fetal life. The analyzed parameters of malleus (a, b, c, d1, d2, e) in the over fetal life period increased adequately by 14.02%, 11.22%, 16.70%, 12.80%, 12.01%, 21.98%, incus by (a, b, c1, c2, d, e) - 7.61%, 11.48%, 11.40%, 23.59%, 12.14%, 14.94%, stapes by (a, b, c, d, e, f) - 6.28%, 7.66%, 8.40%, 4.54%, 4.54%, 4.16%. In the over fetal life period increase of weight of malleus by 22.05%, incus by 26.49%, stapes by 11.57% was also observed. Described parameters of ossicles system are very important with respect to classification to the operations improving hearing in the system convecting of vibration of the tympanic membrane in children.

Adult↗
PubMedDate not supplied

[Kinematics of the ear ossicles].

The paper details the movements of the auditory ossicula in exposure to low- and high-frequency sounds. Low-frequency sound causes the hammer to vibrate along the line crossing the tympanic anterior and posterior folds. Because of the screw shape of the anvil-hammer junction these hammer movements produce dislocation of the long anvil process along the base of the stapes. Due to the spherical shape of the anvil-stapes junction the above shift gives rise to pedal movements of the base of the stapes by the transverse short axis of the vertibular window. High-frequency sound waves are transmitted by the crest from the walls of the middle ear cavity to the short hammer process. This produces its rotation responsible for the anvil long process shift across the vestibular window, up and down. These vibrations result in vibrations of the base of the stapes crosswise the vestibular window.

Acoustic Impedance Tests↗
PubMed1997

Regulation of D-aspartate release and uptake in adult brain stem auditory nuclei after unilateral middle ear ossicle removal and cochlear ablation.

In young adult guinea pigs, the effects of unilateral ossicle removal and cochlear ablation were determined on transmitter release from glutamatergic presynaptic endings and glutamate inactivation via uptake. (i) D-[3H]Aspartate release and uptake were measured in subdivisions of the cochlear nucleus (CN) and in nuclei of the superior olive (SOC) and auditory midbrain (MB) up to 145 days after placing the lesions. Activities were compared to those from age-matched unlesioned controls. Fiber degeneration was visualized histologically. (ii) In the ipsilateral CN, changes in release and uptake were governed by the type of lesion. Ossicle removal produced sparse pruning of fibers only after 112 days and decreased release and uptake at 145 days, consistent with regulatory weakening of excitatory glutamatergic transmission. Cochlear ablation deafferented the CN, producing deficient release and uptake at 2 days and abundant fiber degeneration at 7 days. Subsequently, the residual release and uptake increased in magnitude, consistent with strengthening of excitatory glutamatergic transmission. (iii) In the contralateral CN, after either lesion, changes in release and uptake usually matched those in the ipsilateral CN. Thus, the auditory pathway associated with the lesioned ear probably provided cues for the regulation of synaptic strength in the contralateral CN. (iv) Both lesions increased release in the SOC and MB, and uptake in the SOC, consistent with strengthening of excitatory glutamatergic transmission. Sparse fiber degeneration, suggesting axonal pruning, appeared in the SOC and MB after cochlear ablation. (v) The strengthening of excitatory glutamatergic transmission may facilitate and maintain symptoms such as loudness recruitment and tinnitus which often accompany hearing loss.

Animals↗
PubMed1998

Plastic changes in glycine and GABA release and uptake in adult brain stem auditory nuclei after unilateral middle ear ossicle removal and cochlear ablation.

[i] In young adult guinea pigs, the effects of unilateral ossicle removal and unilateral cochlear ablation were determined on [14C]glycine or [14C]GABA release and uptake measured in subdivisions of the cochlear nucleus (CN), the superior olivary complex, and the auditory midbrain, after 2 or 5, 59, and 145 postlesion days. Activities were compared to those of age-matched, unlesioned controls. [ii] [14C]Glycine release declined bilaterally in the anteroventral and dorsal CN after ossicle removal and in the dorsal CN after cochlear ablation. [iii] Transient elevations of release occurred at 59 days in the ipsilateral posteroventral CN ([14C]glycine) and bilaterally in the ventral nucleus of the lateral lemniscus ([14C]GABA) after ossicle removal, and bilaterally in the medial superior olive ([14C]glycine) after cochlear ablation. [iv] In the medial nucleus of the trapezoid body, [14C]GABA release was depressed bilaterally 5 days after ossicle removal, but was elevated at 145 days contralaterally after ossicle removal and ipsilaterally after cochlear ablation. [v] In the contralateral central nucleus of the inferior colliculus, [14C]GABA release was elevated persistently after ossicle removal. After cochlear ablation, release was elevated at 5 days, near the control at 59 days, and elevated again at 145 days. [vi] After both lesions, [14C]glycine uptake was elevated bilaterally in the CN and medial superior olive. [14C]GABA uptake became depressed by 59 or 145 days bilaterally in the auditory midbrain. [vii] These changes may stem from regulation and may contribute to mechanisms that generate symptoms such as loudness recruitment and tinnitus, which often accompany hearing loss.

Age Factors↗
PubMed1994

[Minor malformations of the ear ossicles. New classification and therapeutic results].

We tried to classify 46 minor malformations in 5 groups: 0: Normal ossicular chain, almost normal tympanic membrane but small atretic plate around malleus handle. I: Fixation of the malleus head. II: Normal ossicular chain but fixation of the footplate with or without abnormality of the facial nerve. III: Lack of a part of the ossicular chain with or without abnormality of the stapes. IV: Severe malformation of all the ossicular chain. We operated upon 4 malformations of type 0, 8 of type I, 10 of type II, 14 of type III and 10 of type IV. An air-bone gap within 20 dB was achieved in only 15 cases. As a matter of fact, in 9 cases the facial nerve covered the oval window; there were 4 pseudo-Mondini; ossiculoplasty was performed on a totally modified footplate in one case.

Abnormalities, Multiple↗
PubMed1987

[The ear ossicle joints in the scanning electron microscopy image].

The incudo-stapedial joint has mostly been accepted as a true diarthrotic joint. In the older literature, however, the histological structure of the incudo-malleal joint has been controversial. Its character as a true joint has been stressed only by the sporadic histologic studies in the recent decades. Although SEM, with its spatial image and high magnification, is especially suitable for the investigation of joint surfaces--as orthopaedic studies have shown--this modern method has so far not been used for studying the ossicular joints. Even in high magnification, the normal ossicular joints show smooth surfaces similar to the typical big joints of the body. To maintain this high degree of differentiation of the delicate hyaline cartilage, a balanced equilibrium of strain and relief must be kept. Nature seems to attach great importance to the postulated protective role of the human ossicular joints.

Adult↗