Sensory innervation of urogenital organs of fourth month female embryo.

Abstract

The innervation of urogenital organs in a fourth month female em-bryo may be cotlined as follows. In the distal part of the ureter, unbranched, and on rarer occasions, simple branched sensory terminations may be found in the propria. How-ever, intraepithelial fibres and glomerular terminations are not yet formed. In the bladder, only unbranched and simple branched terminations are observed in formation. In rare cases, intraepithelial fibres were proved to exist. In the urethra, sensory fibres run into the propria from the outside wall. Their terminations are also unbranched and simple branched ter-minations, and no genital nerve bodies nor intraepithelial fibres were ob-served. In the propria of the uterus, a small number of unbranched termina-tions are found. This fact seems to indicate the presence of sensory ter-minations in adult human uterus. In the vaginal wall, scarcely any sensory fibres are verified. Only near the outer orifice, a small number of unbranched terminations were observed. In the vestibulum vaginae, the number of sensory fibres is much larger, the terminations being mostly of unbranched type. In the labium minus, the number increases further, unbranched and simple branched terminations being in evidence, but no complex branched terminations nor genital nerve bodies are found. As sensory terminations in the clitoris, Pacinian bodies may be men-tioned first. Their number is yet very small, and their formation is found around the tunica albuginea of the corpus cavernosum clitoridis, and on rare occasions, in the corpus cavernosum glandis. It is interesting to note that Pacinian bodies are formed in places in the fascial formation around the pubis, unrelated with the clitoris. These Pacinian bodies are naturally in the inchoate stage of development by fourth month embryo. In the clitoris, no genital nerve bodies are found, not even a trace of them. Sensory terminations other than the Pacinian bodies are repre-sented by unbranched and extremely simple branched terminations, which are formed in the tunica propria glandis and the connective tissue in the praeputium in particular. In the terminal parts of the branches of n. dorsalis clitoridis, frequently very thick sensory fibres are seen branching out in several branches, which seems to show the fact that one thick nerve fibre may run out in a number of nerve terminations, or probably in many genital nerve bodies. In conclusion, I may mention the interesting fact that intraepithelial fibres are already seen in formation in the common epithelium between the inner lamella of the praeputium and the glans clitoridis, although, maybe, in a much lower stage of development than in a seventh month embryo (Seto), and that they are clearly distinguished into two separate types (Seto) in formation.