Nerve contributions to the pelvic plexus and the umbilical cord

Abstract

Serial sections of human embryos and fetuses reveal that the sacral nerves which contribute fibers to the pelvic plexus often have dorsal, ventral, and oblique communicating rami. The ventral rami resemble the white rami of upper thoracic nerves and some of their fibers pass close by or through the chain ganglia and into the pelvic plexus. The sizes of the ventral rami are often in inverse proportion to that of the pelvic splanchnic nerves. That is, when the pelvic splanchnic nerves are poorly developed, the ventral rami are large, and conversely, when the pelvic splanchnic nerves are well developed, these rarni are small. The pelvic plexus was found to receive fibers from the sympathetic trunk and its ganglia in addition to those from the hypogastric plexus and the pelvic splanchnic nerves.Analysis of the observations made in this study together with a review of the literature in light of the present day classification of nerve fibers raises serious doubts concerning the limits set for the outflow of preganglionic nerve fibers from the spinal cord and the distribution of gray and white rami as described in recent textbooks in terms of their histological and physiological significance.Nerve fibers from the pelvic plexus can be traced along the walls of the bladder and the urachus and along the umbilical arteries into the umbilical cord. In embryos, only a few scattered nerve fibers were found distal to the umbilicus, but in fetuses at term, distinct nerve bundles were identified in the cord. These bundles sent branches to the walls of the umbilical arteries; other branches terminated as "end-nets'' in Wharton's jelly. These nets appeared as fine fibers with nodular swellings at irregular intervals. Innervation of the umbilical arteries was richest within the first few inches of the cord. Beyond this region, the nerves rapidly decreased in number. "End-nets'' were present as far as four inches from the umbilicus. Granular cells resembling Langerhans' cells were found in the cord. Often these cells were closely associated with fine nerve fibers.This study is concerned mainly with the nerve contributions to the pelvic (inferior hypogastric) plexuses. Observations are included on the contributions from the pelvic plexus to the umbilical cord. The general pattern of the nerve pathways of sympathetic fibers through the lumbar splanchnic nerves and the hypogastric plexus and nerves and that of parasympathetic fibers by way of the pelvic splanchnic nerves to the pelvic plexuses are well recognized. However, certain aspects of these pathways are not so well understood.The pelvic plexuses lie in close relation to the lateral surfaces of the pelvic viscera. Each plexus may be divided into regional parts which are named according to the organs to which they are anatomically and physiologically related. Both sympathetic and parasympathetic ganglion cells are found in these plexuses. The AM. J. ANAT., 128: 485-498. parasympathetic cells are thought to have migrated from the sacral segments of the central nervous system...

Topography of the pelvic autonomic nervous system and its potential impact on surgical intervention in the pelvis

“…A still-unanswered question remains: Are there autonomic fibers from the IHP to the posterior aspect of the rectum? Whereas Pearson and Sauter (1970) and Taguchi et al (1999) described such an innervation pattern, we could not verify these findings.…”

“…The observations of the sympathetic and parasympathetic sources of the IHP described in previous reports were verified in our study; however, we expanded upon these studies by presenting a systematic view of the sources and distribution of fibers to and from the IHP. Also, previous reports described the sympathetic sources of the IHP as deriving from sympathetic ganglia S1 to S5 (Davis, 1933;Curtis et al, 1942;Pearson and Sauter, 1970;Walsh and Donker, 1982) and parasympathetic sources from S2 to S5 (Baljet and Drukker, 1981;Walsh and Donker, 1982;Stelzner et al, 1989). We demonstrated a more specific distribution in the participation of different ganglia and ventral rami.…”

Anatomy and Pathology of the Umbilical Cord and Major Fetal Vessels

“…It is possible that these structures relate to the vagal fibers described in embryos by Pearson and Sauter (1969), which are thought to be instrumental in closing the ductus venosus after birth. The same authors subsequently investigated the sacral portions of embryos and found convincing evidence for a neural supply of umbilical arteries (Pearson & Sauter, 1970). Some neural elements terminate before entering the cord, whereas others penetrate it.…”

Umbilical vein constriction at the umbilical ring: a longitudinal study

“…Potent vasoactive substances, such as neuropeptide Y and atrial natriuretic peptide, have been demonstrated in umbilical vein endothelium and may be involved in the local regulation of blood flow16. Nerves have been identified in the umbilical cord at the fetal end17, 18, and some of the nerve endings reaching the media of the vein could be motor nerves18. Although it is not known whether these nerves have any regulatory function, umbilical vein constriction and relaxation at the umbilicus appear to influence the UV blood flow.…”