caa a22 4500 386347352 CHVBK 20180307111816.0 cr unu---uuuuu 161130e198912 xx s 000 0 eng 10.1017/S0022215100111156 doi S0022215100111156 pii (NATIONALLICENCE)cambridge-10.1017/S0022215100111156 Early ossification within the human fetal otic capsule: morphological and microanalytical findings [Elektronische Daten] Besides the use of conventional techniques such as light and polarization microscopy, the present paper proposes the combined use of transmission electron microscopy, secondary and backscattered electron imaging, energy dispersive X-ray analysis and computed tomography for the diagnostic evaluation of ear pathology in the human fetus. These methods were used to revisit the primary calcification front of the fetal otic capsule between 16 and 23 weeks gestational age. Ultramicroscopic evaluation demonstrates similar fetal bone formation to that found in other bones of the human fetus. The formation of the endosteal and periosteal layers is a typical example of early intra-membranous ossification. The enchondral layer is made up of fibrillar bone, laid down around the calcified cartilage remnants. Microchemical analysis indicates a significantly higher Ca/P ratio in the endochondral layer with respect to the endosteum and periosteum. The consequences of a lower Ca/P ratio in the endosteal layer are discussed in view of calcium homeostasis and inner ear function. Copyright © JLO (1984) Limited 1989 Declau F. ENT Department, University of Antwerp, Wilrijk, Belgium Jacob W. Electron Microscopy Department, University of Antwerp, Wilrijk, Belgium Dorrine W. Chemistry Department, University of Antwerp, Wilrijk, Belgium Appel B. Neuroradiology Department, Middelheim Hospital, Antwerp, Belgium Marquet J. ENT Department, University of Antwerp, Wilrijk, Belgium The Journal of Laryngology & Otology Cambridge University Press 103/12(1989-12), 1113-1121 0022-2151 103:12<1113 1989 103 JLO https://doi.org/10.1017/S0022215100111156 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1017/S0022215100111156 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Declau F. ENT Department, University of Antwerp, Wilrijk, Belgium NATIONALLICENCE 700 1- Jacob W. Electron Microscopy Department, University of Antwerp, Wilrijk, Belgium NATIONALLICENCE 700 1- Dorrine W. Chemistry Department, University of Antwerp, Wilrijk, Belgium NATIONALLICENCE 700 1- Appel B. Neuroradiology Department, Middelheim Hospital, Antwerp, Belgium NATIONALLICENCE 700 1- Marquet J. ENT Department, University of Antwerp, Wilrijk, Belgium NATIONALLICENCE 773 0- The Journal of Laryngology & Otology Cambridge University Press 103/12(1989-12), 1113-1121 0022-2151 103:12<1113 1989 103 JLO CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-cambridge