The development of the periurethral glands in the human female

Abstract

Serial sections have been prepared of the urethras and the lower urogenital area of female fetuses of 50 mm., 80 mm., 128 mm., and 224 mm. crown-rump lengths, and of six adult female urethras. Wax reconstructions of portions of these preparations have been made to illustrate certain points discussed. Anlagen of the periurethral glands were observed for the first time in a 50 mm. fetus. These anlagen appear as four small, solid buds arising from the ventral and lateral surfaces of the urethra above the müllerian tubercle. In the 80 mm. fetus urethral gland anlagen are evident as numerous buds, without branches, developing from the dorsal, ventral and lateral sides of the urethra above the müllerian tubercle. Branched glands are present in the 128 mm. fetus but at this stage, as in the younger embryos, only the area of the urethra above the müllerian tubercle gives rise to them. In the 224 mm. fetus the glandular arrangement is similar to that in the adult. At this stage the lower urethra reveals one diverticular-like pocket but no glandular structures are to be seen arising from the vestibule or the vaginal epithelium. In the adult urethras studied the orifices of all periurethral or para-urethral glands arise from the urethral mucosa. In none of the fetal or adult urethras examined in this series were any glandular structures observed arising from the urogenital sinus below Müller's tubercle, in the vaginal epithelium nor in the vestibule. These observations support Pallin's belief that the female periurethral glands are homologous with only that portion of the male prostate arising cephalad to the urogenital sinus. That this is for the most part true is evident from the material presented here-with. However, the classical work of Wyatt and of Johnson, who found occasional glands arising from the urogenital sinus below the müllerian tubercle make an attempt at correlation of these divergent findings necessary. Several explanations are possible: The most logical would seem to be that occasional small glands in the lower portion of the urethra are carried downward on the lips of the somewhat trumpet-shaped opening of the urethra into the upper end of the urogenital sinus. As a result, the indistinct union of the urethra and the urogenital sinus makes it appear that these periurethral glands are of sinus origin. It is also possible that occasional small true sinus glands are present in the female but that they are infrequent in number and not present in all individuals. Several small, straight, solid tube-like buds were noted in the 80 mm. fetus arising from the lower walls of the urogenital sinus. These were considered anlagen of Littre's glands which are profuse in the distal male urethra. It would appear from the material studied that the larger para-urethral ducts and glands (Skene's) arise from anlagen above the müllerian tubercle; that they are similar to the other periurethral glands in origin and structure; and, that they, like the periurethral glands, are homologues of that portion of the male prostate which develops above the union of the mesonephric ducts with the urogenital sinus.