Innervation to and Within the Uterus. ∗

Abstract

In the course of certain experiments it became desirable to know the nature of the distribution of nerve paths from the pelvic plexus to their ultimate destinations in the uterus. Accordingly, we have performed a series of experiments in suitable ovariectomized rabbits. In some of these the parametrium was cut through progressively and the uterus left intact. In others, the uterus was cut first and the parametrium left entire. These experiments showed that when some spot in the middle third of the parametrium is cut, the uterus above the level of section fails to respond to lumbar sympathetic stimulation, even though the uterus itself is still intact. With the parametrium uncut, but the uterus severed, the whole organ still responds to pre-sacral nerve stimulation. Experiments on the essentiality of the utero-vaginal junction (containing the uterine cervical ganglia) were performed. This whole region, including cervices, could be excised without modifying the responses of the uterine cornua when the lumbar sympathetic nerves are stimulated. Section of a selected small region of the parametrium at the level of and close to the site of the cervices, promptly abolishes uterine responses to sympathetic nerve stimulation.

In other experiments point stimulation of suitable places on the parametrium was made progressively from the tubal end, caudad. It was found in favorable experiments that the uterus contracts more or less locally, directly opposite the site of parametrial stimulation. This local contraction spreads very slowly in both directions, cephalad and caudad.

Our results indicate, therefore, that lumbar motor sympathetic fibers pass close to the utero-vaginal junction and then dip more or less deeply into the parametrium as they pass toward the upper end of the uterus. Along their whole course they give off fibers to the uterus, innervating rather restricted regions, and do not contribute to a widespread, diffuse plexus within the uterine walls.