What is the nerve innervation of genitalia?

Nerve Innervation of the Genitalia

The genital innervation involves both somatic and autonomic nerve pathways, with the pudendal nerve providing the primary sensory innervation through the dorsal nerve branches, while autonomic pathways from the pelvic plexus control vasocongestion and sexual response. 1, 2

Somatic Innervation

• The pudendal nerve serves as the primary somatic innervation of the external genitalia, providing essential sensory and motor functions for sexual behavior, erectile function, and micturition 1
• In males, the dorsal nerve of the penis (DNP) originates from the pudendal nerve in Alcock's canal and ascends to the penile bodies, providing sensory innervation to the penis 3
• In females, the dorsal nerve of the clitoris (DNC) follows a similar path, originating from the pudendal nerve and providing sensory innervation to the clitoral bodies 2
• The human glans clitoris receives approximately 10,280 myelinated nerve fibers through bilateral dorsal nerves of the clitoris, making it an extremely sensitive structure 4
• Large complex nerve endings containing neuron-specific enolase (NSE) and vesicular glutamate transporter 1 (VGluT1) are abundant in the dermal papillae of the clitoris, representing specialized mechanoreceptors 5

Autonomic Innervation

• The cavernous nerves originate from the vaginal nervous plexus in females and travel along the 5 and 7 o'clock positions of the urethra before reaching the clitoral bodies 2
• At the hilum of the clitoral bodies, branches of the cavernous nerves medially cross the dorsal nerve of the clitoris and travel alongside it before merging at the glans 2
• In males, the penile innervation is primarily somatic in the extra-albugineal sector and primarily autonomic in the intracavernosal sector proximally, while distally, both sectors are almost exclusively supplied by somatic nerve fibers 3
• The autonomic innervation (parasympathetic) is responsible for the vasocongestion response during sexual arousal, controlling blood flow to erectile tissues 1
• Sympathetic innervation contributes to ejaculation in males and plays a role in vascular tone regulation 1

Functional Significance

• Genital afferent stimulation excites spinal autonomic nuclei and supraspinal sexual centers in both genders, highlighting the importance of sensory feedback in sexual response 1
• Pudendal nerve circuitry serves essential purposes for sexual behavior, erectile function, penile rigidity, ejaculation, and micturition 1
• Males and females share a comparable pattern of genital afferent neuroanatomy and neurophysiology, with similar sexual and micturition reflexes in both genders 1
• The parasympathetic nervous system provides excitatory (cholinergic) and inhibitory (non-adrenergic, non-cholinergic) innervation affecting genital vasocongestion 6
• Sympathetic input is generally inhibitory to genital vasocongestion, with the exception of its role in ejaculation 6

Clinical Implications

• Damage to the autonomic innervation of the vaginal wall during procedures like tension-free vaginal tape (TVT) could lead to altered lubrication-swelling response 2
• The dorsal nerve of the clitoris is located inferior to the pubic ramus and may be preserved during certain surgical procedures like tension-free vaginal tape-obturator (TVT-O) 2
• Understanding the dual somatic and autonomic innervation of genitalia is crucial for preserving sexual function during pelvic surgeries 1, 2
• Coactivation of nociceptors containing calcitonin gene-related peptide (CGRP) but not substance P within mechanoreceptor complexes may explain certain pain disorders of the external genitalia 5
• Genital afferent stimulation can be harnessed as a therapeutic modality to amplify autonomic and somatic activity within the genitalia, potentially beneficial in improving sexual response and function 1