Mucous glands in the developing human nose.

In 56 fetuses the development and spread of the nasal glands were studied by three different whole-mount methods. Development starts anteriorly in the nose and proceeds with a given regularity backward. The anterior nasal, serous glands are found only most anteriorly in the nose. They are laid down in the 11th week by the formation of long ducts that grow backward. Small seromucous glands start forming in the 13th week. They gradually spread backward in the middle and inferior meatus and hence to the medial and lateral surfaces of the inferior and middle conchae. They are present in all parts of the respiratory region except in a small area above and behind the nasal vestibule and behind the conchae, Bowman glands start developing in the 16th week, in the roof of the nose, and gradually spread down through the entire olfactory region. They are very small, tubular, and serous. Bythe 23rd week gland formation has been completed.