Development of Mucous Glands in the Human Eustachian Tube

Abstract

The object of the present study was to elucidate the development of the mucous glands in the Eustachian tube. 47 tubes from 33 foetuses aged 11 to 27 menstrual weeks were studied by the PAS, PAS-Alcian blue, and osmium whole mount methods. All tubes were freed and stained in toto, and all glands were examined and counted. Gland formation was found to start in the 12th menstrual week in the lateral wall of the rhinopharynx, caudally to the tubal orifice, and to spread towards the tube. At the beginning of the 13th menstrual week gland formation started in the tube, first in the medial, and 10 days later in the lateral wall. The glands were laid down first in the pharyngeal orifice and gradually spread into the tympanic direction, reaching the middle of the tube in the course of 14 days. Up to the 17th menstrual week about 7 new glands were laid down weekly, from the 17th to the 20th week approx. 9. During the subsequent weeks the intensity of gland formation gradually decreased, and after the 26th week there is probably no further gland formation. By the 27th week the tube contained an average of 86 glands, 50 in the pharyngeal quarter and 36 in the second quarter. No glands were present in the tympanic half. In the medial wall there was an average of 46 glands, in the lateral wall 40. By means of quantitative studies the development and growth of the individual glands are elucidated.