The extrinsic innervation of the pelvic organs in the female rat.

The extrinsic innervation of the pelvic organs in neonatal and adult female rats is described. Mainly an in toto acetylcholinesterase method is used; moreover, acetylcholinesterase is demonstrated in sections. The hypogastric plexus is defined as the nerve plexuses caudal to the inferior mesenteric ganglia comprising the uterine cervical ganglia and various smaller ganglia. The origin of the hypogastric plexus is formed by the hypogastric nerves, bundles of nerve fibers from the lumbar and cranial part of the sacral sympathetic trunks, bundles of nerve fibers from the inferior mesenteric ganglia and the pelvic nerves. The origin of the caudal part of the hypogastric plexus is also constituted by the pudendal nerves. The uterine nerves are derived from the ovarian nerves, the uterine cervical ganglia, the hypogastric nerves and the lumbar sympathetic trunks. The nerves to the urinary bladder are derived from the ganglionated nerve plexuses in the mesometrium as well as from the uterine cervical ganglia. The vaginal nerves are derived from the uterine cervical ganglia, the ganglionated nerve plexus in the mesometrium and the pudendal nerve. The rectal nerves are derived from the ganglionated inferior mesenteric plexus, the uterine cervical ganglia and the pudendal nerves. The hypogastric plexus in the rat is in many respects more complex than is known from the literature. These anatomical data are relevant for instance to experimentators who use the pelvic autonomic plexuses in the rat as a model system for the analysis of autonomic neuronal regulation systems in mammals.