[The development of the organum vomeronasale system in human embryos 19--40 mm in crown-rump length].

Age-related changes in the organon vomeronasalis (VO) and related structures have been described in normal human embryos of 19, 25, 28 and 40 mm in crown-rump length and in the embryo of 19 mm in crown-rump length during abnormal development in the uterine tube. The fourth branch of the VO nerve appeared in the 25 mm embryo. Signs of asymmetry and degenerative VO changes were analyzed in the 25 and 40 mm embryos. A supposed vomeronasal ganglion has been described. The possibility of fetuses at the late stages of prenatal development using the VO system is discussed.