The spermatic ganglion in humans: an anatomical update

The male gonad receives nerve fibers from the autonomic ganglionic system. By the present study, we aimed to bring detailed evidences, topographic and structural, on the spermatic ganglia (SG) in humans, as suppliers of autonomic fibers for the testis. We performed retroperitoneal dissections in 25 formalin-fixed human male adult cadavers. Histology used the Hematoxylin-Eosin and we also used Bielschowsky silver stains. Immunohistochemistry used antibodies for tyrosine hydroxylase. In 20÷10 specimens, we identified left spermatic ganglia (LSG) at the aortic origin of the left testicular artery (LTA); in five specimens the LTA left the renal artery but LSG were juxtaposed on the aorta at about the level of origin of a normal LTA. In 15÷25 cadavers, there were right spermatic ganglia (RSG) related to the right testicular artery (RTA) that in 12 cadavers had a precaval disposition. A specimen with retrocaval RTA presented an inferior renal ganglion, supplying both the renal and the RTA. The SG presented renal, lumbar and intermesenteric roots. The inferior branch of the SG connected it to the inferior mesenteric plexus while its infero-lateral branch adjoined the testicular artery. Microscopy confirmed the SG as nervous ganglia and the respective neuronal populations were tyrosine hydroxylase positive, allowing us to consider these ganglia as sympathetic. We bring here the first-time evidence of the SG topography and cathecolaminergic nature in humans; this ganglion may influence the male gonad via the inferior mesenteric plexus and via the vascular path of the testicular artery.