ABSTRACT
BACKGROUND: The vasculature of the nasal mucosa in the human fetus so far has not been investigated morphologically by modern techniques. METHODS: Nasal blood vessels were studied in 18-21-week-old human fetuses by corrosion casting and scanning electron microscopy. RESULTS: The general vascular architecture was similar to that described for adult humans, with (1) a dense network of subepithelial capillaries, (2) a mucosal layer of larger vessels, predominantly veins, and (3) large arteries located near the perichondrium. Specific vessel types characteristic of the nasal mucosa and important for its functions in adults, such as cavernous veins or cushion veins, were, however, absent in the fetuses, although probable precursor forms of cushion veins could be observed. The arteriovenous anastomoses had the form of short bridges, and no tortuous or glomerular anastomoses present in the mature nasal mucosa were found. CONCLUSIONS: The underdevelopment of some vascular areas is postulated to reflect the functional immaturity of the respiratory system in the fetus.
