Development of the olfactory nerve: its relationship to the craniofacies.

Although absence of the olfactory bulbs is a relatively common occurrence seen in holoprosencephaly, in Kallman syndrome, and in a number of malformation syndromes, the extent to which it determines olfactory nerve development, as well as the part it plays in the morphogenesis of the nasal structures, is unknown. Cases of arhinencephaly ascertained at autopsy were studied in an effort to better understand the relationships between the olfactory nerve, bulb, and facies. Based on these studies, it is concluded that both olfactory receptor cells and olfactory nerves are present in arhinencephaly, that the olfactory nerves did not make contact with the brain in these cases, that the presence of olfactory nerves is independent of the severity of the central nervous system malformation, and that the shape of the nasal structures is not dependent on the presence of the olfactory nerve.