The embryologic development of the human anterior nasal aperture.

During the final period of embryogenesis, the nasal pit is clearly apparent in the Carnegie stage 15 embryo, and extends backwards into the oral cavity forming the nasal sac. In the stage 19 embryo of about 7 weeks, abundant epithelial proliferation into the lumen forms the nasal meatal plug. The complete recanalization of this meatal plug occurs in the 16-17 week fetus, and not in the 24th week of fetal life as is generally accepted in textbooks on human embryology. The findings of the present study of the embryology of the anterior nares can well explain the anomalies of the human anterior nares aperture.