Colorectal and uterine movement and tension of the inferior hypogastric plexus in cadavers

Twenty eight embalmed human cadavers were examined. Pelvic visceral structures were displaced by very gentle 5？N unidirectional tension and the associated movement of the endopelvic fascia containing the inferior hypogastric plexus that this caused was measured.Most movement of the fascia containing the inferior hypogastric plexus was obtained by pulling the rectosigmoid junction or broad ligament of the uterus. The plexus did not cross any vertebral joints and the fascia containing it did not move on pulling the hypogastric nerve.Uterine and rectosigmoid displacement produce most movement of the fascia containing the hypogastric nerve plexus, potentially resulting in nerve tension. In the living this might occur as a consequence of menstruation, pregnancy or constipation. This may be relevant to somatovisceral reflex theories of the effects of manual therapy on visceral conditions.Beneficial effects have been reported for chiropractic and manual therapy treatment of conditions affecting pelvic viscera such as the bowel, bladder and uterus [1-4], although study design often makes meta-analyses difficult [5-7]. In contrast, very little is known about the mechanisms involved. Neural-based theories are often offered as explanations- and sometimes justifications- for treatment [8-10], but there is little human evidence to support them. This weakens the overall rationale for choosing chiropractic and manual therapy protocols for conditions with underlying visceral aetiologies even if outcome studies suggest a benefit. The aim of this study is to test the possibility that movement of pelvic viscera in humans might put mechanical tension on visceral nerves. This may help define the structural basis of some somatovisceral interactions where adverse mechanical tension of nerves is presumed to be operating [8,9]. One likely candidate here is the inferior hypogastric plexus, since it is in close anatomical proximity to- and innervates- much of the pelvic viscera [11,12]. It is