[On the endochondral ossification of the otic capsule: formation of the globuli ossei and the interglobular spaces (author's transl)].

To our knowledge this is the first transmission electron-microscopic study on endochondral bone formation in the otic capsule. The formation of the rat's globuli ossei and interglobular spaces is studied with special regard to Manasse's (1897) contributions who suggested the globuli ossei's cells to be "embryonic cartilage cells" which have "metaplased" to bone cells. Since then his opinion has found ample confirmation by subsequent light-microscopic works until today. The results reported here indicate that the chondrocytes of the erosive zone die in the endochondral layer of the otic capsule. Mononuclear cells ahead of the invasion front partially resorb the remnants of the intracellular substances. Cells which originate from perivascular elements of invasive capillary buds enter the empty lacunae of the cartilage remnants and become osteoblasts. They form the globuli ossei by producing bone matrix and become osteocytes later on.