FORAMEN THYROIDEUM - A COMPARATIVE-STUDY IN EMBRYOS, FETUSES, AND ADULTS

The incidence and characteristics of foramen thyroideum (FT) in embryo nic and/or fetal larynges have not been established. In the present st udy, 90 adult larynges and 53 embryonic-fetal larynges were studied, T he incidence of FT during the embryonic-fetal period (57%) was statist ically different from the adult period (31%) (P = 0.005). All the FT f ound in the adult period contained vessels and/or nerves, while in the embryonic and fetal period only 63% presented neurovascular elements (P < 0.001). The origin of FT in the embryonic period and its persiste nce during adult life is discussed.