Corpus: Pelvic splanchnic nerves

The Nervi splanchnici pelvici carry parasympathetic fibres from S2 to S4. They have their origin neurons in the lateral horn of these spinal cord segments and travel to the inferior hypogastric plexus, where they are switched to the 2nd neuron. As they also innervate the pelvic and genital organs, they are also referred to as nervi erigentes.

The pelvic nervi splanchnici are the only parasympathetic nervi splanchnici. Among other things, they control defecation, micturition, erection and ejaculation. They run in the same region as the sacral splanchnic nerves, which are responsible for the sympathetic innervation of the pelvic organs.

The nerves in the area of the Cannon-Böhm point are of particular importance as they take over the parasympathetic innervation of the colon from the vagus nerve, which ends at this point.

According to more recent findings based on the molecular genetic examination of the nerve cells, the nervi splanchnici pelvici are sympathetic nerves, contrary to the previous doctrine.^[1] The cells express Olig2 and Foxp1, the same genes as corresponding sympathetic nerve cells in the thoracolumbar region.

• Schünke et al. Prometheus Learning Atlas of Anatomy, 4th edition, Georg Thieme Verlag, 2015