Bony labyrinth

About: Bony labyrinth is a research topic. Over the lifetime, 284 publications have been published within this topic receiving 6477 citations. The topic is also known as: osseous labyrinth & otic capsule.

Planar relationships of the semicircular canals in man.

Abstract: Principal-component analyses were determined on a series of points measured from the dissected bony labyrinth of ten human skulls, resulting in planar equations for each of the six semicircular canals. Following this, angles were calculated between the ipsilateral canal planes, between opposite synergistically acting canal planes and between each canal and the Reid stereotaxic planes. Results indicated that pairs of ipsilateral canals were nearly perpendicular, with the exception of the angle formed between the anterior and horizontal canal (mean = 111 °). Pairs of contralateral synergistic canal planes formed angles of 19° between right and left horizontal canal planes and 23–24° between vertical canal pairs. The horizontal canals formed an angle of 25° with the Reid horizontal plane. Mathematical equations of the semicircular canals were used to predict the optimal head position for rotational and caloric stimulation.This investigation was supported in part by U.S. Public Health Service Grant NS-06658; ...

Structure of the Mammalian Cochlea

Abstract: The cochlea within the inner ear contains the cells responsible for the perception of sound. Unfortunately for researchers, the structures of interest are housed in a rather inaccessible part of the skull, totally embedded in bone. In spite of this, the anatomy was well described in the mid-nineteenth century by Retzius, Huschke, Reissner, Kolliker, Deiters, Hensen, and Corti, names familiar even to present-day cochlear anatomists. From their studies, it was known that the cochlea is composed of a bony labyrinth, within which is found the cellular structures comprising the membranous labyrinth. These are easily seen in a section taken through the cochlea in a plane parallel to its long axis (Fig. 2.1).

Classification and Current Management of Inner Ear Malformations.

Abstract: Morphologically congenital sensorineural hearing loss can be investigated under two categories. The majority of congenital hearing loss causes (80%) are membranous malformations. Here, the pathology involves inner ear hair cells. There is no gross bony abnormality and, therefore, in these cases high-resolution computerized tomography and magnetic resonance imaging of the temporal bone reveal normal findings. The remaining 20% have various malformations involving the bony labyrinth and, therefore, can be radiologically demonstrated by computerized tomography and magnetic resonance imaging. The latter group involves surgical challenges as well as problems in decision-making. Some cases may be managed by a hearing aid, others need cochlear implantation, and some cases are candidates for an auditory brainstem implantation (ABI). During cochlear implantation, there may be facial nerve abnormalities, cerebrospinal fluid leakage, electrode misplacement or difficulty in finding the cochlea itself. During surgery for inner ear malformations, the surgeon must be ready to modify the surgical approach or choose special electrodes for surgery. In the present review article, inner ear malformations are classified according to the differences observed in the cochlea. Hearing and language outcomes after various implantation methods are closely related to the status of the cochlear nerve, and a practical classification of the cochlear nerve deficiency is also provided.

Comparative review of the human bony labyrinth.

Abstract: The bony labyrinth inside the petrous part of the temporal bone houses the organs of hearing and balance Being functionally linked with sensory control of body movements and located in a part of the basicranium that is closely associated with the brain, this structure is of great interest in the study of human evolutionary history However, few aspects of its morphology have been studied in nonhuman primates This review compares the bony labyrinth of humans with that of the great apes and 37 other primate species based on data newly acquired with computed tomography combined with previous descriptions With body mass taken into account, consistent differences are found between the size of the semicircular canals in humans, the great apes, and other primates In particular, the arcs of the anterior and posterior canals are larger in humans than in the African apes The functional implications of semicircular canal dimensions for registering angular head motion are evaluated in relation to locomotor behavior Biophysical models, comparative studies, and some neurophysiological experiments all support a link between semicircular canal size and agility, or more specifically the frequency contents of natural head movements, but the evidence on the exact nature of this link is ambiguous It is concluded that any link between the characteristic dimensions of the human canals and locomotion will be more complex than a simple association with the broad categories of quadrupedal vs bipedal behavior The functionally important planar orientations of the semicircular canals are similar in humans and the African apes as well as in many other species In contrast, other aspects of the human labyrinth differ markedly in shape, following a pattern that seems to reflect the characteristic architecture of the human basicranium Indeed, it is found that labyrinthine and basicranial shape are interspecifically correlated in the sample, and in most respects the human morphology is consistent with the general trend among primate species Differences in brain growth and development are proposed as the predominant factor underlying both the unique shape of the human labyrinth as well as the interspecific labyrintho-basicranial correlations

Prenatal growth and development of the modern human labyrinth

Abstract: The modern human bony labyrinth is morphologically distinct from that of all other primates, showing derived features linked with vestibular function and the overall shape of the cranial base. However, little is known of how this unique morphology emerges prenatally. This study examines in detail the developing fetal human labyrinth, both to document this basic aspect of cranial biology, and more specifically, to gain insight into the ontogenetic basis of its phylogenetically derived morphology. Forty-one post-mortem human fetuses, ranging from 9 to 29 weeks gestation, were investigated with high-resolution magnetic resonance imaging. Quantitative analyses of the labyrinthine morphology revealed a number of interesting age-related trends. In addition, our findings show that: (1) the prenatal labyrinth attains an adult equivalent size between 17 and 19 weeks gestation; (2) within the period investigated, shape changes to all or most of the labyrinth cease after the 17-19-week size maturation point or after the otic capsule ossifies; (3) fetal cochlea development correlates with the surrounding petrosal morphology, but not with the midline basicranium; (4) gestational age-related rotations of the ampullae and cochlea relative to the lateral canal, and posterior canal torsion are similar to documented phylogenetic trends whereas other trends remain distinct. Findings are discussed in terms of the ontogenetic processes and mechanisms that most likely led, in part, to the emergence of the phylogenetically derived adult modern human labyrinth.