Bone modeling in the otic capsule of the rat.

Bone modeling determines postuterine gross bone architecture. During growth the shape and proportion of all bones are continuously adapted to function by surface resorption and surface formation. This process is responsible for exchange of most primary endochondral type bone with lamellar endosteal or periosteal bone. By a combination of microradiography, tetracycline fluorescence and osteoid staining of undecalcified material bone modeling in the otic capsule of the rat was studied and compared to well-known modeling patterns in rat long bones. Perilymphatic spaces were found to be enclosed in a layer of primary bone resistant to resorption associated with surface modeling. It is proposed, that this drift barrier is maintained by a control mechanism present inside the perilymphatic space.