LIV The Development of the Auditory Ossicles, the Otic Capsule and the Extracapsular Tissues

Anson, Barry J.; Bast, Theodore H.; Cauldwell, Earl W.

doi:10.1177/000348944805700303

Cited by 44 publications

(18 citation statements)

References 19 publications

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“…Ossification has been shown to develop from 14 centers merging by 23 wks 38 to form a bony capsule which has been divided into three distinct layers: the inner cortical bone (inaccurately called “endosteal layer”) lining the perilymphatic space, the trabecular bone area (“Middle Layer”) and the outer cortical bone (incorrectly called “periosteal layer”) as seen on the 2D μ CT images (Fig. 4C).…”

Section: Discussionmentioning

confidence: 99%

Inner ear ossification and mineralization kinetics in human embryonic development - microtomographic and histomorphological study

Richard

Courbon

Laroche

et al. 2017

Sci Rep

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Little is known about middle and inner ear development during the second and third parts of human fetal life. Using ultra-high resolution Microcomputed Tomography coupled with bone histology, we performed the first quantitative middle and inner ear ossification/mineralization evaluation of fetuses between 17 and 39 weeks of gestational age. We show distinct ossification paces between ossicles, with a belated development of the stapes. A complete cochlear bony covering is observed within the time-frame of the onset of hearing, whereas distinct time courses of ossification for semicircular canal envelopes are observed in relation to the start of vestibular functions. The study evidences a spatio-temporal relationship between middle and inner ear structure development and the onset of hearing and balance, critical senses for the fetal adaptation to birth.

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Section: Discussionmentioning

confidence: 99%

Inner ear ossification and mineralization kinetics in human embryonic development - microtomographic and histomorphological study

Richard

Courbon

Laroche

et al. 2017

Sci Rep

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“…Ossification of the cartilaginous labyrinthine capsule starts from ossification centres between embryonic weeks 16-21 when the labyrinth has reached its maximum expan sion [Bast, 1930;Anson et al, 1948], These cartilage remnants are not replaced by bone during ossification and later on the globulus osseus cells cannot produce sufficient osteoid to fill the interglobular spaces [ShinIzi-Ziba, 1911]. In the globuli ossei of young rabbits, cartilage cells were found which in autoradiograms reacted like bone cells [Hildmann, 1977], Using semithin sections in adult rabbits, we observed bone cells in the lacunae of the globuli ossei.…”

Section: Discussionmentioning

confidence: 99%

The interglobular spaces in the endochondral layer of the osseous labyrinth

Rauchfuss¹

1980

Cells Tissues Organs

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The endochondral layer of the osseous labyrinth in the rat, golden hamster, mouse, guingea pig, pig, rabbit, cat, dog and monkey was studied and compared with that of man. (1) With the exception of the mouse and golden hamster, interglobular spaces were found. (2) In all species but the rat, the interglobular spaces contain acid mucopolysaccharides. An analogy between these structures and the ‘basophilic islands’ (basophile Inseln) is discussed. (3) Extension, arrangement, direction, occurrence and frequency of interglobular spaces vary within each species so that no constant relations could be found, which are also lacking in man. Possible reasons for the persistence throughout life of interglobular spaces in the osseous labyrinth of man and some mammals are discussed.

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“…Around the inner ear, the numerical density of viable osteocytes exhibited a biphasic decline with increasing age initiated by an exponential decay and followed by a linear decline. The high initial density and the first rapid decline may reflect the gradual addition of less cellular skeinbone to the highly cellular primary endochondral spongiosa (osseous globules and interglobular spaces) during cancellous compaction of the endochondral capsule, a process that is generally considered complete at the age of 2–3 years (Anson et al,1948). From this age, a slower linear decline ensues, during which osteocytes are lost in senescence and apoptosis and not replenished by bone remodeling, which is virtually absent in perilabyrinthine bone (Sørensen,1994).…”

Section: Discussionmentioning

confidence: 99%

The Viability of Perilabyrinthine Osteocytes: A Quantitative Study Using Bulk‐Stained Undecalcified Human Temporal Bones

Bloch

Kristensen

Sørensen

2012

The Anatomical Record

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Bone remodeling is highly inhibited around the inner ear space, most likely by the anti-resorptive action of the inner ear cytokine osteoprotegerin (OPG) entering perilabyrinthine bone through the lacuno-canalicular porosity (LCP). This extracellular signaling pathway depends on the viability of individual osteocytes. The objective of this study was to evaluate the patency of the LCP at different ages. Sixty-five bulk-stained undecalcified human temporal bones and 19 ribs were selected to span the ages from the 30th gestational week to 95 years. Osteocytes from inside a 2-mm wide perilabyrinthine zone of bone were identified by 3D vector calculations and the numerical densities estimated with an optical dissector and compared to age-matched ribs. From a high fetal count of 90,000 cells/mm 3 , the density of viable capsular osteocytes declined rapidly to 73,000 cells/mm 3 at three years of age, and non-viable osteocytes increased inversely. After 3 years, this decline/increase continued at a much slower rate. The densities of viable as well as non-viable osteocytes and the rates of change were much higher in perilabyrinthine bone compared to ribs. Only after the age of 80 years had the density of viable capsular osteocytes declined to the level of ribs. The bi-phasic osteocyte kinetics reflects different development stages. The high initial density of viable osteocytes may secure a life-long anatomical route for inner-ear OPG despite the unique accumulation of non-viable osteocytes. Clustering of non-viable osteocytes may cause local aberrations in the signaling system by closure of the LCP.

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LIV The Development of the Auditory Ossicles, the Otic Capsule and the Extracapsular Tissues

Cited by 44 publications

References 19 publications

Inner ear ossification and mineralization kinetics in human embryonic development - microtomographic and histomorphological study

Inner ear ossification and mineralization kinetics in human embryonic development - microtomographic and histomorphological study

The interglobular spaces in the endochondral layer of the osseous labyrinth

The Viability of Perilabyrinthine Osteocytes: A Quantitative Study Using Bulk‐Stained Undecalcified Human Temporal Bones

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