[On the elasticity of the ligamentum anulare. Experimental investigations into human temporal bone preparations with the help of an electromagnetic probe (author's transl)].

An electromagnetic probe was used to investigate the elasticity of the ligamentum anulare in human temporal bone preparations. The static measurement showed with preserved auditory ossicles but without tympanic membrane an average displacement of 37--41 micron at a pressure of 10 mN. Five different points of measurement did not lead to any significant differences; we must assume that the elastic properties of the ligamentum anulare are completely equal. After the removal of the malleus and incus, the displacement increased by only 2.2 micron, by another 4.2 micron if the stapes tendon was severed. Under these circumstances, too, a completely even elongation is proved to occur in all sections of the ligamentum anulare. Different pressures lead to a no-load characteristic which is linear in the 5--20 mN range, suggesting excellent elastic properties of the ligamentum anulare. From these data we may assume that the oscillation behavior of the basis stapedis approaches that of a membrane pump, with a linear transmission of great oscillation amplitudes possible.