DEVELOPMENT OF HUMAN FACIAL CANAL AND FACIAL NERVE / 解剖学报

ABSTRACT

The development of the human facial canal and the facial nerve of 229 temporal sides from 11 weeks fetuses to infancies were studied by histological method. The results showed that the facial canal was formed by the membranous ossification and by cartilaginous ossification. The lateral wall, inferior wall of the horizontal segment and the eminous segment, the superior wall of the labyrinthine segment of the facial canal were formed by the membranous ossification. The sequence of the membranous ossification had some regularities. The rest of the facial canal was ossified in the cartilaginous bone. The development of the facial nerve grew in advanced embrylogical age. The length and width diameters of the facial nerve in the facial canal were almost the largest in size before birth. The size of the facial nerve to that of the facial canal is kept in a more or less constant proportion. It was found that the facial norve was largest at the distal portion of the labyrinthine segment of the facial canal and smallest at the stylomastoid foramen.We put forward the conclusion that the disturbances of the membranous ossification in any portion of the facial canal and the anomalies of the pneumatization of the mastoid process were the main causes for the deficiency of the facial canal.