There are three different nerve systems which either suppress, allow, or build sexual arousal. These three nerve systems are all part of the autonomic nervous system which maintains all of our internal functions.
- The first system is the Sympathetic Nervous System. It is represented on this diagram in orange/red. The SNS joins sensory/motor fibers of the Pudendal nerve, and together they travel underneath the deep pelvic floor muscles and combine with other nerves to become the Dorsal Nerve of the Clitoris. This nerve continues all the way to the glans/tip of the clitoris.
- The second is the surveillance/permissive portion of the Parasympathetic Nervous System. This system is shown in green. The PNS, using the right Vagus nerve, travels outside of the spinal column bones, where it blends into the pelvic plexus on the way to the Dorsal Nerve of the Clitoris. The pelvic plexus fibers ride above ("supralevator" pathway) the deep pelvic floor muscles all the way from back to front. Near the pubic bone, these nerve fibers dive through the pelvic floor muscles, where they join the pudendal nerve to become the Dorsal Nerve of the Clitoris and travel all the way to the tip of the clitoris.
- The third system is the nitric-oxide producing nerves of the pelvic plexus, itself a portion of the PNS (also called the Inferior Hypogastric Plexus, also Pelvic Splanchnic Nerves). It is represented on this diagram in aqua blue. As above, the pelvic plexus courses between the spine [S2, S3, S4] and the genitals, travelling along the superior surface of the deep pelvic floor muscles ("supralevator" pathway), until just before the pubic bone where they dive down, join the pudendal nerve, and form the Dorsal Nerve of the Clitoris. These nerves produce nitric oxide gas and facilitate blood flow into the clitoral caverns. If enough blood flows into the caverns, the pressure from the blood causes swelling of the caverns, which pushes on the overlying tunica, and causes engorgement and stiffness of the clitoris, called an erection.
Why does this matter?
These nerve pathways are frequently discussed, but less frequently understood. Yet they are discrete nerve pathways, and their form and function have been well documented by scientists.
But doesn't the Sympathetic Nervous System control Ejaculation?
Yes. In cis-males who were exposed to sufficient testosterone in utero, cells called the "spinal ejaculatory center" form in their spine from T10-L1. These cells are not found in any cis-female mammals studied to date, although some argue about rats. The reason the SNS is involved in ejaculation because coordinating secretion from 3 glands+epididymis and propulsively emitting semen is a technically coordinated event that requires simultaneous function which the SNS excels at.
It is one of the compelling arguments against cis-"female ejaculation", as there are no cells to coordinate propulsion and no need for coordination.