Hypogastric nerve

The hypogastric nerve is the nerve that transitions between the superior hypogastric plexus and the inferior hypogastric plexus. The hypogastric nerve enters the sympathetic chain at T12-L3.

The hypogastric nerve begins where the superior hypogastric plexus splits into a right and left plexus. Each of these divisions is considered a hypogastric nerve. The hypogastric nerve continues inferiorly on its corresponding side of the body, where it descends into the pelvis to form the inferior hypogastric plexus. Contents of the right and left hypogastric nerves include preganglionic and postganglionic sympathetic fibers from vertebral levels of T10 to L2, passing through the spinal nerve roots of T12-L3.

The hypogastric nerve provides sympathetic innervation. It 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.

Source : Wikipedia