Histological verification of the prehypogastric and ovarian ganglia confirms a bilaterally symmetrical organization of the ganglia comprising the aortic plexus in female human cadavers.

The aortic plexus is a network of sympathetic nerves positioned along the infrarenal abdominal aorta. Recently, we characterized the aortic plexus and its ganglia (inferior mesenteric, left/right spermatic, and prehypogastric ganglion) in males; however, the literature minimally describes its anatomy in females. In the present study, we conducted the first histological examination of the left and right ovarian ganglia, while also investigating whether females, like males, exhibit a prehypogastric ganglion. The ganglia were dissected from embalmed (n = 32) and fresh (n = 1) human cadavers, and H&E staining was used to confirm the presence of a left ovarian ganglion in 31/31 specimens, a right ovarian ganglion in 29/29 specimens and a prehypogastric ganglion in 25/28 specimens. Comparable to the topographic arrangement in males, there is a bilateral organization of the ganglia comprising the aortic plexus in females. More specifically, the left and right ovarian ganglia were positioned in close relation to their respective ovarian artery, whereas the prehypogastric ganglion was positioned within the right cord of the aortic plexus, contralateral to the inferior mesenteric ganglion. Using immunohistochemistry, it was shown that all ganglia from the fresh cadaver stained positive for tyrosine hydroxylase, thereby confirming their sympathetic nature. Having provided the first topographical and histological characterization of the ovarian and prehypogastric ganglia in females, future studies should seek to determine their specific function.

Anatomy of the nerves and ganglia of the aortic plexus in males.

It is well accepted that the aortic plexus is a network of pre- and post-ganglionic nerves overlying the abdominal aorta, which is primarily involved with the sympathetic innervation to the mesenteric, pelvic and urogenital organs. Because a comprehensive anatomical description of the aortic plexus and its connections with adjacent plexuses are lacking, these delicate structures are prone to unintended damage during abdominal surgeries. Through dissection of fresh, frozen human cadavers (n = 7), the present study aimed to provide the first complete mapping of the nerves and ganglia of the aortic plexus in males. Using standard histochemical procedures, ganglia of the aortic plexus were verified through microscopic analysis using haematoxylin & eosin (H&E) and anti-tyrosine hydroxylase stains. All specimens exhibited four distinct sympathetic ganglia within the aortic plexus: the right and left spermatic ganglia, the inferior mesenteric ganglion and one previously unidentified ganglion, which has been named the prehypogastric ganglion by the authors. The spermatic ganglia were consistently supplied by the L1 lumbar splanchnic nerves and the inferior mesenteric ganglion and the newly characterized prehypogastric ganglion were supplied by the left and right L2 lumbar splanchnic nerves, respectively. Additionally, our examination revealed the aortic plexus does have potential for variation, primarily in the possibility of exhibiting accessory splanchnic nerves. Clinically, our results could have significant implications for preserving fertility in men as well as sympathetic function to the hindgut and pelvis during retroperitoneal surgeries.

Characterizing the autonomic neural connections between the abdominal aortic and superior hypogastric plexuses: A multimodal neuroanatomical study.

The aortic plexus serves as the primary gateway for sympathetic fibers innervating the pelvic viscera. Damage to this plexus and/or its associated branches can lead to an assortment of neurogenic complications such as bladder dysregulation or retrograde ejaculation. The neuroanatomy of this autonomic plexus has only recently been clarified in humans; as such, the precise function of its constituent fibers is still not clear. Further study into the functional neuroanatomy of the aortic plexus could help refine nerve-sparing surgical procedures that risk debilitating neurogenic complications, while also advancing understanding of peripheral sympathetic circuitry. To this end, the current study employed an in vivo electrostimulation paradigm in a porcine model, in combination with lipophilic neuronal tracing experiments in fixed, post-mortem human tissues, to further characterize the functional neuroanatomy of the aortic plexus. Electrostimulation results demonstrated that caudal lumbar splanchnic nerves provide primary control over the porcine bladder neck in comparison to other constituent fibers within the aortic plexus. Ex vivo human data revealed that the prehypogastric ganglion contains a significant number of neurons projecting to the superior hypogastric plexus, and that these neurons are arranged in a topographic manner within the ganglion. Altogether, these findings suggest that a pivotal sympathetic pathway mediating bladder neck contraction courses through the caudal lumbar splanchnic nerves, prehypogastric and inferior mesenteric ganglia and superior hypogastric plexus.