Adult Temporal Bones Research Articles

Hyaluronate production by the inner ear during otic capsule and perilymphatic space formation

Otosclerosis has been hypothesized to result from a disorder of the extracellular matrix of the cartilaginous rests present in the adult temporal bone. Matrix relationship to bone formation and remodeling, as well as the fact that the pathogenesis of otosclerosis is expressed by the action of both of these processes, strongly suggests that more knowledge is needed about the process of otic capsule development. In pursuit of this goal, otic complexes were explanted from mouse embryos that ranged in age from 10.5 to 16 days old and were then exposed to 3H-glucosamine (50 microCi/ml) for 6 hours in vitro. Total labeled glycosaminoglycans (GAGs) and labeled hyaluronate content of each age group of otic explants were measured, and the results were compared to a developmental series of the otic regions of whole embryos stained with either toluidine blue or alcian blue. Increases in the synthesis of the total GAGs were observed on embryonic day 11 and for a prolonged period extending from gestation day 13.5 through day 16. The first increase of GAGs occurred at the initiation of metachromasia and positive staining by toluidine blue of the region of aggregated periotic mesenchyme cells that form the otic capsule. The second increase in GAGs was correlated with chondrification of the capsule. Hyaluronate production revealed a different pattern. Synthesis of hyaluronate exhibits peaks at 10.5, 12.5, and for an extended period of from 13.5 to 14.5 days of gestation.(ABSTRACT TRUNCATED AT 250 WORDS)

Postnatal growth of the human temporal bone. Implications for cochlear implants in children.

Recent interest in cochlear implantation for children has made it important to understand how postnatal growth of the ear will affect such devices. In this study, the postnatal growth of the labyrinth, middle ear, and mastoid was measured in three dimensions using radiographic and temporal bone data. Measurements were made from histologic sections of 48 temporal bones from children and compared to adult temporal bones. Radiographic measurements were made from 253 sets of skull radiographs of children and compared to adult skull series. In the three dimensions measured, there was no postnatal growth of the labyrinth and little variation in size between individuals. Measurements of the middle ear showed greater variation between individuals than measurements of the inner ear, but growth only in the distance from stapes footplate to the tympanic membrane. The mastoid showed growth in all three dimensions: length, width, and depth. The pattern of growth for mastoid length and width appears to follow a double logistic model, with differences between males and females. The growth in mastoid depth is smaller and appears to follow a single exponential curve. The implications for cochlear implantation in children are discussed.

側頭骨ＣＴに関する基礎的研究 大切片標本との解剖学的比較検討

The morphology of macrosections of the normal adult temporal bone were correlated with high resolution computed tomographic findings of 6 axial, coronal and sagittal sections.1) The micro-structure of the temporal bone was almost perfectly demonstrated by axial, coronal and sagittal sections. Axial sections provided more information on the structure of the temporal bone than did coronal sections. Sagittal sections gave little information.2) Axial sections effectively demonstrated the facial nerve canal (labyrinthine segment-geniculate ganglion-tympanic segment), majorr petrous nerve canal, short process of the incus, stapes (especially foot plate), and relationship of the malleus head to the incus body.3) Coronal sections were useful in demonstrating the cochlear aqueduct, facial nerve canal (mastoid segment), crista transverse, tensor tympani and ossicle (incus body, incus long process, stapes head, stapes crus).4) Sagittal sections were useful in demonstrating, the facial nerve canal (tympanic segment, mastoid segment), vestibular aqueduct, and the relationship of the malleus head to the incus long process.5) To understand the complicated structure of the temporal bone it was necessary to perform CT in many dimensions. The most useful section was the axial. Coronal and sagittal sections were sometimes useful.

Cochlear aqueduct radiographic anatomy in temporal bone preparations and in sudden hearing loss.

Sudden sensorineural hearing loss appears to have many possible etiologic factors. Shea has presented work indicating that a large cochlear aqueduct (CA) is frequently present on the side of an idiopathic sudden sensorineural hearing loss (ISHL). However, Valvassori, on performing temporal bone tomographic studies on several hundred patients complaining of ISHL, has not found enlargement of the CA in a statistically significant number of these cases. In an attempt to resolve this discrepancy, a single blind study was performed utilizing temporal bone polytomography to evaluate the presence or absence of the CA in 22 adult patients. One-half of these patients had a history of ISHL, while the remaining patients had other complaints as an indication for tomography. In all cases, the CA was identified. The CA was felt to be enlarged in 1 patient suffering from ISHL, in the nonaffected ear of 1 patient with unilateral ISHL, and in 2 control patients. There was, therefore, no positive correlation between CA enlargement and the occurrence of ISHL. In order to further elucidate the radiologic anatomy of the CA, 9 pairs of adult temporal bones removed at autopsy were studied by polytomography after cannulation and injection of radiopaque material. Measurements of the dimensions of the CA and its radiographic anatomy are discussed and compared to measurements obtained from histopathologic evaluation of the temporal bone.

Incisions in tympanoplasty: anatomic considerations and indications.

The endaural, postauricular and transmeatal incisions are the most commonly used surgical approaches for tympanoplasty. Each incision used in tympanoplasty has its own advantages and limitations so that no single approach is the best approach for all tympanic membrane perforations. The incision selected for tympanoplasty should be determined by the location and extent of disease. Forty adult temporal bones were studied to understand the limiting factors for each surgical approach used in tympanoplasty. The external endaural incision has been modified to permit easier visualization of the crescentic endomeatal canal incisions. The anterior external endaural incision allows direct exposure of temporalis fascia, the external meatus, bony canal and perforation involving the posterior tympanic membrane and ossicular chain. The postauricular incision gives direct exposure of the anterior tympanic membrane with preservation of the anterior canal wall skin. The transmeatal approach should be reserved for smaller central perforations with limited risk for squamous ingrowth into the middle ear. In the transmeatal tympanoplasty, the ear canal should permit the use of a speculum large enough to expose the entire perforation.

Zur Heilungs- und Regenerationsf�higkeit der Paukenschleimhaut nach Tympanoplastik

Comparing microscopic investigations of mucous lining specimens taken from adult temporal bones having clinical normal middle ears with biopsies from the tympanon of patients following tympanoplasty resulted in an overall correspondence of epithelial and subepithelial cell structure of normal tympanic mucosa and those with operative treatment following chronic inflammation. Considering both histo-pathological findings on admission and clinical follow-up findings after tympanoplasty, these results confirm our previously stated assumption, although meanwhile doubted by others, that the tympanic mucosa is capable of improving any inflammatory changes and that the initial pathological findings are very seldom responsible for failure of tympanoplasty nor for inflammatory recidivation.

The distribution of neuroglia and schwann cells in the 8th nerve of man.

The 8th cranial nerve has been dissected from 23 adult temporal bones at autopsy and studied histologically. It was found that neuroglial tissue, continuous with that in the brain stem, supported 8th nerve axons to just beyond the mid-point of the nerve. Lateral to this, axons are supported by Schwann cells and neurilemmal sheaths with a short 'junctional zone' intervening. The point at which the transition occurred, from neuroglial to Schwann cell portions, was medial to the porus in 56 per cent of cases, level with the porus in 18 per cent, and within the internal auditory canal in 26 per cent. The relevance of these findings to some aspects of 8th nerve pathology and surgery is discussed.

A scanning electron microscopic study of the normal human stapes.

The structure of the normal human stapes was studied with the scanning electron microscope. Specimens were obtained 48 hours after death from adult human temporal bones free from obvious inflammatory disease. The specimens were fixed, dissected, critical-point dried and coated with gold. In this scanning electron microscopic study an attempt has been made to systematically demonstrate the average scanning electron microscopic features of various areas of the normal human stapes. An emphasis has been placed upon demonstrating as clearly as possible the details previously unclear or unrecognized and duplication of many excellent earlier light and electron microscopic studies has been attempted. The typical appearance of the stapes head, neck, arch, crura and footplate has been presented. It is apparent that there exists a high degree of structural specialization particularly in the stapes arch and footplate area.

A Study of the Topographic Anatomy of the Human Vestibular Aqueduct

Taking consideration of its surgical importance the anatomy of the distal endolymphatic system, especially, dimensions of the vestibular aqueduct were investigated. Twenty-five adult human dry temporal bones were dissected for the study on dimensions and relationships of lumen of the common crus and the internal aperture of the vestibular aqueduct. And sixteen adult human fresh temporal bones were examined by osmic acid staining method on the measurement of whole course of the vestibular aqueduct. As the results, numerical data of the vestibular aqueduct were presented with particular reference to its shape, dimensions, and relationships of its internal aperture. The course and relationships of a para-vestibular canaliculus housing the blood supply of the endolymphatic sac was described.

Fissular region of the otic capsule in relation to otosclerosis.

IN AN investigation based on an examination of more than 300 series of sections, covering specimens from the 6 mm. embryo to the 70 year old adult, the development of the temporal bone and its adult histological structure have been studied, with particular reference to pathological changes in the fissular region of the otic capsule. In this report, which must be brief, the development of the fissular region and the neighboring portions of the otic capsule, the normal adult structure of the same regions and these pathological alterations which occur in and around the fissula which result in one form of deafness will be discussed. The adult temporal bone is "petrous" only where it serves as a bed for the membranous labyrinth. The petrous part is only that portion which houses the otic labyrinth. Marrow and air spaces occupy much of the remaining portion. They are late fetal additions to

Pneumatization of the adult temporal bone, the mastoid portion. An anatomic and clinical study

Pneumatization of the adult temporal bone, the mastoid portion. An anatomic and clinical study

Comparative surgical anatomy of infant, child and young adult temporal bones and mastoid processes (lantern slides and specimens)

Comparative surgical anatomy of infant, child and young adult temporal bones and mastoid processes (lantern slides and specimens)