The development of the ossicular ligaments in the human middle ear.

We examined serially sectioned human temporal bones of fetuses and newborns from Wittmaack's temporal bone collection at the University of Hamburg. At the end of the 3rd month of fetal development, a concentration of mesenchyme arises in the area which later contains the ossicular ligaments. The anlage of these ligaments can be clearly identified in the 4th month of development. The longitudinal axis of the cells in this anlage first runs parallel with the surface of the ossicles. In the further stages of development with increasing fibrillogenesis the cells straighten out according to the physiological stresses. Differentiation of the ligaments is terminated at the end of the 9th month.