Prenatal growth of the human tympanic membrane.

The questions connected with the morphology of developing tympanic membrane are rather inadequately dealt with in the relevant literature. The aim of this article has been the morphometric analysis of the prenatal growth of human tympanic membrane. The experiment was conducted on 33 fetuses aged from the 4th to 8th month of gestation. Significant individual variability of the tympanic membrane measurements was revealed in the material studied. The growth of the structure discussed was bilaterally symmetric during the whole period investigated. The fourth and 7th month of gestation seem to be the crucial stages for the tympanic membrane development. The measurements of the membrane exhibited the highest variability, simultaneously being negatively correlated with the fetal age in that periods. Relatively more intensive growth of the vertical diameter of the membrane was noted in the 5th and 8th months of gestation. In the 8th month of gestation the tympanic membrane reached a vertically elongated shape, typical of the postnatal period. On the basis of our results it is possible to conclude that the quantitative developmental process takes place in the tympanic membrane till the end of the prenatal period, determining the final functional capacity of the structure discussed.