Pudendal Nerve: Structure, Function & Diseases

The pudendal nerve is known as the pudendal nerve. It is considered the most important mixed nerve of the pelvic floor.

What is pudendal nerve?

The pudendal nerve is the pubic nerve. It originates in the sacral plexus (pubic plexus), more specifically in segments S1 to S4. The pudendal nerve marks the largest pudendal plexus branch. It is endowed with vegetative as well as sensitive and motor parts. The pudendal nerve has special importance for the muscles of the pelvic floor, the genitals, and the sphincters.

Anatomy and structure

From its beginning in the pubic plexus, the pudendal nerve, together with the sciatic nerve, exits the lesser pelvis through the infrapiriform foramen. Immediately at this point, the pudendal nerve bends around the spina ischiadica and the sacrospinous ligament. Through the foramen ischiadicus minus it re-enters the pelvis. The further course leads the pudendal nerve into the ischioanal fossa within Alcock’s canal, which is also called the pudendal canal. This is a fascial duplication of the internal iliac sphincter (Musculus obturatorius internus). At the same time, Alcock’s canal represents the most significant constriction of the pudendal nerve. Thus, entrapment of this section poses the risk of pudendal neuralgia. The division of the pudendal nerve into its terminal branches occurs in this area. These are called the dorsal penile nerve in men or the dorsal clitoral nerve in women, as well as the inferior rectal nerves and the perineal nerves. In the male sex, the dorsal side (dorsal side) of the penis is sensitively supplied by the dorsalis penis nerve, while in the female the dorsalis clitoridis nerve is responsible for the sensitive innervation of the clitoris. The nervi rectales inferiores are responsible for the motor supply of the external anal sphincter (Musculus sphincter ani externus). Furthermore, the skin around the anus is sensitively innervated by them. The perineal nerves are responsible for supplying the perineal muscles such as the bulbospongiosus and the external bladder sphincter (Musculus sphincter urethrae externus). In the male, the dorsal side of the scrotum is also supplied by the scrotal nerves posteriores. In females, the nervi labiales posteriores take care of the dorsal supply of the labia majora.

Function and Tasks

The pudendal nerve marks the main mixed pelvic floor nerve. Thus, the sphincters of the bowel, urinary bladder, and genital area are supplied by it. If sensory or motor deficits occur, incontinence is imminent. Likewise, involvement in urinary retention, constipation or sexual dysfunction is within the realm of possibility. Of importance, the pudendal nerve is involved in the stable position of the pelvic viscera, human continence, abdominal press, and sexual functions such as ejaculation in men. The inferior rectal nerves perform the function of providing sensitive sensation to the skin located in the immediate vicinity of the anus. Furthermore, the pubic nerve takes care of the sensitive perception of the perineum, male testicles and female labia. The perineum is the area between the anus and the male scrotum or between the anus and the female vagina (vagina).

Diseases

It is possible for the pudendal nerve to be negatively affected by certain diseases. Foremost among these is pudendal neuralgia. This refers to a rarely occurring neuropathic disease that affects the peripheral nervous system. The resulting pain is attributed to the pudendal nerve. Sometimes unclear pain in the genital region or the pelvis is also called pudendal neuralgia. Women are affected by the disease about twice as often as the male sex. In most cases, a mechanical cause is hidden behind the pudendal neuralgia. This involves a constriction or irritation of the pudendal nerve. For example, pressure on the perineum can occur when riding a bicycle. Pressure damage is also possible during surgical procedures because the patient is positioned on the same part of the body for too long.Other possible causes of pudendal neuralgia include difficult births, injuries to the pelvis such as puncture wounds, gunshot wounds or fractures, endometriosis, constriction of the Alcock’s canal due to connective tissue, vascular diseases of the pelvis, diabetes mellitus, shingles or tumors of the pelvis. Pudendal neuralgia is characterized by severe pain in the perineal and genital areas. While in men the symptoms almost always appear in the perineum and only occasionally in the penis, women suffer from unilateral pain between the external vagina and the anus. The pain can be pressing, dull, stabbing, burning or shooting in. Sensory disturbances or muscle paralysis also sometimes occur. The numbness in turn has a negative effect on the control of defecation or urination in some patients. Thus, in the further course, fecal or urinary incontinence is conceivable. When standing or visiting the toilet, there is often an improvement in the symptoms because pressure is relieved in the pelvis. To treat pudendal neuralgia, the patient is given painkillers. It is also important to treat the triggering underlying diseases. In the context of obstetrics, the so-called pudendal block is sometimes performed. This means that the pain-conducting pathways of the pudendal nerve are blocked when the expulsion phase begins. In this procedure, the doctor injects an anesthetic into the vaginal wall, temporarily numbing the pudendal nerve. In this way, the pain in the vaginal area can be effectively relieved.