Sympathetic innervation by the hypogastric nerve is responsible for the emission of semen into the posterior urethra. Emission is the first phase of male ejaculation (followed by the second phase, expulsion). In contrast, erection is mediated primarily by the parasympathetic nervous system via pelvic splanchnic nerves.Click to see full answer. Also asked, what is the Hypogastric? Medical Definition of hypogastric 1 : of or relating to the lower median abdominal region hypogastric arteriograms. 2 : relating to or situated along or near the internal iliac arteries or the internal iliac veins hypogastric lymph nodes. what is a superior hypogastric plexus block? The superior hypogastric plexus block is a procedure used to decrease pain in the pelvis. The superior hypogastric plexus is an area in front of the spine where nerves lie that transport pain sensations from the internal organs of the pelvis. Beside this, is the superior hypogastric plexus sympathetic or parasympathetic? The superior hypogastric plexus contains the sympathetic function for the urogenital system. Parasympathetic function for the urogenital system is supplied by the S 1-L4 nerve roots that contribute to the pelvic splenic nerves. Somatic function from Sl, S2, S3, and S4 is carried predominantly by the pudendal nerve.How long do Hypogastric plexus blocks last?Longer term relief usually begins in two to three days, once the steroid begins to work. How long the pain stays away is different for each patient. For some, the relief lasts weeks. For others, the relief lasts years.