Vomeronasal organs and nerves of Jacobson in the human fetus.

The vomeronasal organs and nerves of Jacobson were found on both sides of the nasal septum in a 28-week human fetus. The vomeronasal organ in the human is a tubular structure with an opening into the nasal cavity anteriorly and closed posterior end. The vomeronasal nerve is distributed equally to the medial and lateral aspects of the organ, courses along the nasal septum and goes through the cartilaginous cribriform plate with the olfactory nerve. The cellular configuration of the vomeronasal organ is similar to the olfactory neuroepithelium. No areas of receptor-free epithelium were found in the vomeronasal organs. Intraepithelial blood vessels and mitotic figures were not observed in the epithelium of the vomeronasal organs at 28 weeks. The lack of intraepithelial blood vessels and mitoses may suggest that the vomeronasal organs are undergoing degeneration at 28 weeks of gestation.